# Sealed vs. Ported and SQ ... Myth or Fact ?



## JAG

Time for me to stir the pot once again .... He he he ...
I will bet this thread ends up VERY long , and with enough techno babble to baffle Einstien.  

Here's the skinny : Every day or two , I read where one respected member or another states that ported can sound just as good as sealed , when it comes to tone , speed , blending , and just straight up SQ .... I've heard the BEST ported designs , and I'm just not buying it  
I do feel that ported can sound VERY good , but I have NEVER ONCE heard a ported enclosure that had the transient speed and tone of a great sealed enclosure ..... *So here's a thread that should allow everyone to air out their experience , tricks , tips , and technical flim-flam about just how one does go about getting ported to stack up.* It needs to be able to play from 80 hz and down , so let's hear it.

Gentlemen , start your subs ....


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## MidnightCE

With slight EQ work, my ported IDMAX in 2.4 @ 28hz sounded fantastic. MHO, better than sealed at 1.1. I never did get it to blend right with sealed, but ported, blended easily. Nothing special, just a lot of trial and error.


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## bobditts

Up until recently I was using a pair of 12" MTX 8500s. If you dont know anything about these beasts, they are the MTX equivelant to the JL W7 line. They weigh 50lbs a piece and can handle a lot of power. anywho, I experimented a lot with these subs as far as what enclosure they would sound best in. First I tried your standard spec sealed box and that didnt work so well. then I moved up to a 7.5ft^3 ported enclosure tuned to about 48hz with the subs and the port firing into the cabin of the car (its a sedan). It sounded very loud and thats about it. Then I tried a much smaller ported enclosure (I think it was around 3.5 or 4ft^3) tuned to 32hz with the subs and the port aiming at the rear of the trunk. I really liked this setup and would have kept it if I could just stop imagining other possibilities. The SQ of this setup was amazing for these subs. very articulate and precise. Couldnt have been happier - or so I thought at the time. Next I tried the pair of 12"s in an IB configuration with the subs firing at the back of the rear seats. This was by far the worst setup ever for these subs. the bass was extremely sloppy and the bass response was terrible. it was extremely peaky around 40hz or so. Next I tried an upfiring enclosure with each sub in its own sealed chamber. The subs were firing through the holes in the rear deck where the rear speakers used to be and bouncing of the rear glass towards the front of the vehicle. I was quite pleased with this setup but it was lacking something that I could quite pinpoint that my second ported enclosure had. The SQ was pretty decent but just wasnt as full as the ported design.


Long story short (cliff notes) For those particular subs, the best SQ enclosure that I was able to find was a smallish ported design tuned in the low 30s.


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## tyroneshoes

you can just get a deeper flatter response with a properly designed ported box. It will roll off lower what a sealed box will al though eq can fix this, and increase output. I have heard both designs sound amazing but its a preference in the tone of the bass. To me ported can still blend and hit like sealed, but play lower flat and louder. I usually try to tune around 27-29 hz but it depends on the woofer.


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## 8675309

tyroneshoes said:


> you can just get a deeper flatter response with a properly designed ported box. It will roll off lower. I have heard both designs sound amazing but its a preference in the tone of the bass. To me ported can still blend and hit like sealed, but play lower and louder. I usually try to tune around 27-29 hz but it depends on the woofer.


x2

I am a firm believer in both. The better SQ boxes I have heard use closer to the minimum required box. For example I will use a driver that worked great. It was a Hart Topaz 12 year 93. Not much to the driver and only had to have 150 RMS and 1.5 - 3 cube ported. The driver had a 1watt efficiency of 93 db or something like that. I modeled the box in a 1.5 cube tuned to 40 Hz and it sounded great. It hit lower without any boominess than 2 equivalent 12's in a sealed box and still had the snap of a sealed box. 

I believe you can get more out of a ported than you can sealed. The downfall of today is most people that hear ported boxes are either

A. Not built correctly
B. Built for SPL with a +3 db bump or higher


In the past 5 years I have only heard a handful of ported boxes that were built for SQ. 

That is why if I am going to port, I use a 10 or smaller, pref an 8. Although I am talking this I am actually going to change to a pair of CDT Audio MS100's that have to have a sealed box just because I have always wanted a set.


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## andthelam

I thought sealed would yield a flatter response. In my experience, Sealed boxes reproduce a flatter, tighter, less output, less low but blendier type of bass. Ported boxes sound boomier, louder, and deeper bass IMHO. 

Also even both at 24db/ slope I found that the Butterworth type x-overs give more upfront bass than L-Riley, anyone else have experience w/ this.


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## CMR22

AVI said:


> I've heard the BEST ported designs , and I'm just not buying it


So what exactly are the "BEST" ported designs?


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## Mr Marv

AVI said:


> Time for me to stir the pot once again .... He he he ...
> I will bet this thread ends up VERY long , and with enough techno babble to baffle Einstien.
> 
> Here's the skinny : Every day or two , I read where one respected member or another states that ported can sound just as good as sealed , when it comes to tone , speed , blending , and just straight up SQ .... I've heard the BEST ported designs , and I'm just not buying it
> I do feel that ported can sound VERY good , but I have NEVER ONCE heard a ported enclosure that had the transient speed and tone of a great sealed enclosure ..... *So here's a thread that should allow everyone to air out their experience , tricks , tips , and technical flim-flam about just how one does go about getting ported to stack up.* It needs to be able to play from 80 hz and down , so let's hear it.
> 
> Gentlemen , start your subs ....



*"It needs to be able to play from 80 hz and down , so let's hear it."*

I think that's the key phrase there^^^^^. I have built literally hundreds of enclosures over the last 7-8 years and I have _never_ heard one that could dig down deep _*and*_ play up to 80 hz as well as a properly built/tuned sealed enclosure.


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## 8675309

You can still achieve a flat response with a ported box. What I have found to work best in a ported box are basic drivers. I did a pair of Vifa PL 10's in a ported box and they sounded great. I did 4 Dayton 8's the cheap ones for a friend and they sounded great. Not like a JL W7 or Kicker L7 ported enclosures, which in my opinion sound boomy.


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## DS-21

AVI said:


> I've heard the BEST ported designs , and I'm just not buying it
> I have NEVER ONCE heard a ported enclosure that had the transient speed and tone of a great sealed enclosure .....


One of those two sentences is clearly in error. Most likely the first one.


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## bassfromspace

If you haven't heard a ported setup sound as good as a sealed setup, that speaks, IMO, more to the quality of the tuning and the integration of the midbass and sub rather than to a deficiency in the STYLE of box used.


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## MidnightCE

what about passive radiator? hmn


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## 60ndown

AVI said:


> Time for me to stir the pot once again .... He he he ...
> I will bet this thread ends up VERY long , and with enough techno babble to baffle Einstien.
> 
> Here's the skinny : Every day or two , I read where one respected member or another states that ported can sound just as good as sealed , when it comes to tone , speed , blending , and just straight up SQ .... I've heard the BEST ported designs , and I'm just not buying it
> I do feel that ported can sound VERY good , but I have NEVER ONCE heard a ported enclosure that had the transient speed and tone of a great sealed enclosure ..... *So here's a thread that should allow everyone to air out their experience , tricks , tips , and technical flim-flam about just how one does go about getting ported to stack up.* It needs to be able to play from 80 hz and down , so let's hear it.
> 
> Gentlemen , start your subs ....


i have run sealed boxes (or bandpass) always because i believed sealed was the only way to achieve sq.

for fun recently i aquired an 18" sub and built a 6.5 cube ported crx box for it.

it sounds better than my 12w7 in a sealed box?

im officially a convert. ported can sound as good as sealed imo.

maybe better?


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## Mr Marv

bassfromspace said:


> If you haven't heard a ported setup sound as good as a sealed setup, that speaks, IMO, more to the quality of the tuning and the integration of the midbass and sub rather than to a deficiency in the STYLE of box used.


I'll agree midbass integration is an important factor as I have heard *excellent* sounding ported set-ups in systems where the midbass could play _*with authority*_ down below 50-60hz or so but as AVI said and I agree with I have _never_ heard a ported design _that could play *from 80hz down* as well as a sealed enclosure_. 

That's my story and I'm sticking to it


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## MiniVanMan

A sealed enclosure will generally produce a flatter group delay and phase plot. How that's going to translate to an in-car reproduction is unknown in any given application. When you start reflecting off of surfaces your phasing can get quite a bit out of whack as opposed to the originally produced wave. 

So when somebody says a sealed enclosure seems to blend better with their front stage, their probably not lying. At the lower end of the ported enclosure's response, the phase will be dramatically different than the upper end (i.e. 80 hz). Now granted, the frequencies that this is starting to happen at, and be very noticeable, are frequencies the sealed enclosure is fighting to reproduce, even with EQ. Now this is a generality, and in essence only valid when all other variables are the same. Like I said before, phasing can get screwed up by all sorts of other variables, and not surprisingly, many of them exist in a car. 

So, what does a phase difference equate to. Well, when something is out of phase, that frequency becomes very prominent, or rather stands out. This is pretty common knowledge in the SPL community as it's a trick to get your subwoofer to appear a lot louder. It won't produce higher SPL numbers, but when sitting in the car, it will seem louder. To the SQ person, this can be a problem in that we like our sub's frequency response to blend better with the front stage. 

So, what does a ported enclosure provide? Low end extension, and a generally flatter response down to it's low end. By going with a smaller box, tuned low, you can reduce your group delay, and phasing variations. This could account for the difference in "SQ" that you hear. However, you start to lose the low end extension the ported design affords you. It can still be better than a sealed enclosure, so it's an option in many cases. Extended bass shelfs in a car are pretty useless in my opinion for anything that would resemble an SQ installation. 

All this being said, it comes down to what you want, and what you're willing to sacrifice. Nothing is perfect, and you just do the best you can, with a lot of trial and error. I've found mid sized ported enclosures, tuned low seem to be the best compromise for me. Take me out of the minivan and put me in a Civic, and that may change real quick.


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## npdang

The question on my mind is how do you know for certain it's the enclosure type, and not something else (say implementation or design) that causes the ported box to sound "slower"?


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## 300Z

IMHO I think it's a lot driver dependent. most of these drivers aren't specifically designed for ported boxes. With that said there are very few sealed subs I would take over a ported old school GTi.


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## JAG

Mr Marv said:


> *"It needs to be able to play from 80 hz and down , so let's hear it."*
> 
> I think that's the key phrase there^^^^^. I have built literally hundreds of enclosures over the last 7-8 years and I have _never_ heard one that could dig down deep _*and*_ play up to 80 hz as well as a properly built/tuned sealed enclosure.


Thank you Mr. Marv ..... 
Please allow me to expound on what you said above .... As a shop owner , it simply not pratical for me to try and get people into a system with 4 or 5 amps , dedicated mid-bass drivers that are of the 10" variety , *and subs that play from 50hz down ...* That's right , true subwoofers that play below 50hz .... Hell , that is easy as pie to get right. *But try and get a sub to play flat from 80 hz down to 20hz .....*
90% of my customers have systems that need a sub to play from 80hz and down .... and do it well. Transient speed without blurring and overhang .... Crisp , tight , and authoratative tonality ... and low end energy .... THIS is what makes a sub great for me. THIS is not always easy to accomplish from 80hz and down ..... JMO


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## JAG

npdang said:


> The question on my mind is how do you know for certain it's the enclosure type, and not something else (say implementation or design) that causes the ported box to sound "slower"?


Hmmm.... There seems to be a fair amount of questioning , as to my personal experience with ported subs ..... I have been doing this for 23 years , and have indeed seen some of the best ported designs. *I've heard IASCA winning systems with ported subs , and thought they would sound better sealed * 
If I can tune hundreds of cars per year , and do it well , tell me why I couldn't also tune cars with ported enclosures ? *Answer is : I CAN ...*
But when that ported enclosure is tuned to it's fullest potential , I still hear things that a sealed enclosure could be doing a better job of , *to MY ears*.
Probably the very best ported design i have played with to date , was a Diamond Audio D6 12" sub in a small ported enclosure , and tuned to about 31hz ..... It sounded fuggin GREAT !!!!! But when that same sub was placed in a 1.2 cu ft sealed box , it sounded even better


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## JAG

Guys .... My starting this thread was NOT an attempt to argue with anyone. My opinion is just that , an opinion .....
However , my intent was to start an educating thread .... One that could offer up possible solutions to those of us who would love to see ported designs that impress us ....
I like learning , and often start threads like this , just to see what I can learn. So offer up something of value , but please , quit trying to pick apart my opinion. I'm not here to argue , only to share knowledge.


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## bassfromspace

AVI said:


> Thank you Mr. Marv .....
> Please allow me to expound on what you said above .... As a shop owner , it simply not pratical for me to try and get people into a system with 4 or 5 amps , dedicated mid-bass drivers that are of the 10" variety , *and subs that play from 50hz down ...* That's right , true subwoofers that play below 50hz .... Hell , that is easy as pie to get right. *But try and get a sub to play flat from 80 hz down to 20hz .....*
> 90% of my customers have systems that need a sub to play from 80hz and down .... and do it well. Transient speed without blurring and overhang .... Crisp , tight , and authoratative tonality ... and low end energy .... THIS is what makes a sub great for me. THIS is not always easy to accomplish from 80hz and down ..... JMO


Why must it be 80hz? That number in and of itself seems rather arbitrary (assuming you don't deviate much from that number). I fail to see why you guy's haven't been able to find a sub that can play from 80hz down. Honestly, that number should be easy for any speaker that call's itself a sub (including attaining all the qualities you described).


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## JAG

bassfromspace said:


> Why must it be 80hz? That number in and of itself seems rather arbitrary (assuming you don't deviate much from that number). I fail to see why you guy's haven't been able to find a sub that can play from 80hz down. Honestly, that number should be easy for any speaker that call's itself a sub (including attaining all the qualities you described).


Because 80 hz is the x-over point that we have found to work the best , in about 90% of all the cars we do ....


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## JAG

This thread is simply not going like I pictured it. I think most all of you missed the intent of the thread. So I'm going to stop replying , and just watch and read where it goes from here.

Cheers to all ...


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## CMR22

AVI said:


> Time for me to stir the pot once again





AVI said:


> Here's the skinny : Every day or two , I read where one respected member or another states that ported can sound just as good as sealed , when it comes to tone , speed , blending , and just straight up SQ .... I've heard the BEST ported designs , and I'm just not buying it
> I do feel that ported can sound VERY good , but I have NEVER ONCE heard a ported enclosure that had the transient speed and tone of a great sealed enclosure .....





AVI said:


> This thread is simply not going like I pictured it. I think most all of you missed the intent of the thread. So I'm going to stop replying , and just watch and read where it goes from here.


What did you picture, everyone agreeing with you? Arc Audio makes the best amps, Boston Acoustics makes the best sub and sealed is better than ported.


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## bassfromspace

AVI said:


> Hmmm.... There seems to be a fair amount of questioning , as to my personal experience with ported subs ..... I have been doing this for 23 years , and have indeed seen some of the best ported designs. *I've heard IASCA winning systems with ported subs , and thought they would sound better sealed *
> If I can tune hundreds of cars per year , and do it well , tell me why I couldn't also tune cars with ported enclosures ? *Answer is : I CAN ...*
> But when that ported enclosure is tuned to it's fullest potential , I still hear things that a sealed enclosure could be doing a better job of , *to MY ears*.
> Probably the very best ported design i have played with to date , was a Diamond Audio D6 12" sub in a small ported enclosure , and tuned to about 31hz ..... It sounded fuggin GREAT !!!!! But when that same sub was placed in a 1.2 cu ft sealed box , it sounded even better



I appreciate the fact that you were willing to start the thread. I think it's important that we discuss thing's of this nature.

I think we have to be frank about the things we believe. In this case, audio is an objective science. Far too often, we've been willing to buy more into stereotypes and magic than we've been willing to buy into the numbers. Once we buy into these myths, we stunt any kind of objective growth. We then cop out and fall back on our subjective experience. It really takes a person who is certain of him/herself to really step out and pursue the true mysteries of audio.

With that said, big midbass drivers with high excursion are our friends. They allow us to properly level match our front and substage and close the integration gap. I think this is the reason ported boxes get a bad rap. Higher output across a certain bandwidth doesn't bode very well for a 6.5" midbass that's displacement limited yet has to keep up with a driver that has several times the displacement capability. This is one of my main knocks against JL with the W7 and other high excursion drivers. Thankfully, it seems that they've answered with their new low depth products.

We'd all do ourselves a service if we changed how we processed our information. Our aim should be to humble ourselves and aim to prove through objective means in combination with subjective action. This would allow all of us to gain first hand experience and advance the knowledge base of the sport.


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## B&K

AVI said:


> Because 80 hz is the x-over point that we have found to work the best , in about 90% of all the cars we do ....


I don't understand based on the topic of the thread as SQ, 80hz and most cars don't go together. Why not ask the same question for 50hz and below.


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## demon2091tb

CMR22 said:


> So what exactly are the "BEST" ported designs?


There is no best, all situations are different, and each situation dependant on transfer function will sound different based on specific driver in question, targeted response based on box size, not to mention a ported box has many more variables, box size in relation to tuning and vise versa, as well as many many other variables.

I always wonder why people ask what is the BEST thing.......when everyone has a subjective opinion of what BEST is considered, dependant on there own tastes, what they need/want, what they can afford, and 100 other things.......There is no best in anything, when things change consistancy goes out of the window.


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## CMR22

demon2091tb said:


> There is no best, all situations are different, and each situation dependant on transfer function will sound different based on specific driver in question, targeted response based on box size, not to mention a ported box has many more variables, box size in relation to tuning and vise versa, as well as many many other variables.
> 
> I always wonder why people ask what is the BEST thing.......when everyone has a subjective opinion of what BEST is considered, dependant on there own tastes, what they need/want, what they can afford, and 100 other things.......There is no best in anything, when things change consistancy goes out of the window.


That was the point of my question to AVI.


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## audionutz

Hello gang!
THis is a topic near and dear to my heart, and like Marv, I have probably built a thousand boxes or more since my inception into this mobile audio world.

I'd like to play the Devil's Advocate here and offer a slightly different way to discuss this thread...

We need to look at subwoofer design per era when we discuss this topic, as the best performance in a given enclosure is primarily affected by the drivers chosen. Drivers of today are what has evolved from the push in the mid '90s to build versatile subwoofers with minimal enclosure size requirements so as to fit in our vehicles easier. With the advent of the kicker solobaric and JL Audio W6 series, "all the bass, half the space" was the new direction the manufacturers began to take. The main way to achieve this is How?
Thats right, build stiffer, heavier cones with meatier suspensions, higher moving mass, and massive motors and FORCE the low notes by lowering your Fs. 
Jump forward a few years, to about '99 , and we begin to see the trend toward building these same small-enclosure woofers with huge power handling, but now we begin to add higher excursion capability by increasing Xmax (remember when Ground Zero came out with the fat surrounds???) These subs are monsters and the sealed enclosure requirements were miniscule.

With the exception of a very few modern brands, the vast majority of todays subwoofers are geared toward working in a small enclosure simply because thats the direction marketing decided to go. We have a few "multi-purpose" woofers that claim to work well in ported designs , but these subs are sealed first, ported afterthought subs....certainly NOT like Pro Sound drivers or the drivers of yesteryear.

So, when we build a ported box with most of todays subs, even subs that claim to work well in ported designs, we tend to get what I refer to as "sonic slop", this same "slop" we hear whan using a driver with too low a Qts and too low an Fs in an Infinite-baffle setup. Too much overhang, "boomy" notes with little or no resolution of pitch changes, poor transient response, inaccurate attack and decay, I can go on and on. Simply put, very few of todays drivers are built to excell in a ported enclosure, therefore, pitting a sealed design against a ported design in an all-out battle of the Sound Q enclosures would have to be further differentiated by stating "X driver sealed" vs "y driver ported". I know of NO CAR AUDIO WOOFER that is the best of both...do any of you?


So, lets jump back from the dawn of autosound to about the mid '90s, right before the Solobaric desings. We had woofers that had HUGE enclosure requirements. The sensitivity ratings were enormous (remember subs like the IDW, the Rockford Punch and later Power series, the MTX RFL stuff, yadda yadda), yet the vast majority of these subs shared a common item....what was it?
You guessed it! The cones were LIGHTWEIGHT, usually made of treated paper, surrounds were corrugated cloth or foam, and Xmax was MINIMAL. The Fs of these old subs rarely reached 30Hz, if that. Why?
They were based on home audio and pro sound concert drivers, thats why. High sensitivity, huge ported boxes, very dynamic and exceptionally quick. The transient response ability of these older woofers was simply amazing, and yes, they could play up to 80Hz no problem, and often played much higher.
However, people wanted more and more woofers in their cars, and with a Punch Pro 15 needing 4 cubic feet net to sound right, what did people begin to do? They began to look toward companies like Kicker who built Sealed-box-only woofers and figured out with a sub that takes less airspace, you can cram more into the same car , or have more room for a cleaner install.

Yes I am paraphrasing like a mofo. The point is, this topic, at least for me, should be tell us your favorite sealed woofer and why, then your favorite ported woofer and why. Follow me?
Or maybe whats the absolute best sounding subwoofer you have ever personally heard and what enclosure was it in?


Back to the topic----
IMHO,
I feel that there are a few drivers that are absolutely fantastic in a selaed box for SQ, with proper tonal resolution, attack, transient response, no distortion to speak of, and will play cleanly from subsonic to almost 80Hz.

However, 

there are a couple drivers that , when placed in a properly-designed ported box, are equal in some areas and better in others, with only ^maybe^ a slight roll-off of the subsonic stuff more quickly than my reference sealed subs.


Shall we discuss specifics here, or what?

Also, what is with the requirement to play a subwoofer up to 80Hz? If we are discussing customers cars off the street who want a good sounding street system, then this topic is not what I thought it was. If we are discussing the uppermost pinnacle of Sound Q utopia, then I argue that in a properly designed system, the front stage should be the dominant factor, and the subwoofer is simply to reinforce the midbass and bottom octaves, NOT to be the primary source of these notes. STRONG midbass presence in the vehicle will be there with a properly-designed and tuned SQ system, and unless the sub is mounted up front, you should never run a sub above roughly 60Hz.
So, do we need some clarification here as to what is expected of this thread?


Sorry for the rambling, its late, and my brain is toast LOL!


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## 60ndown

audionutz said:


> 60Hz.


what slop?




























































e


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## JAG

*The ENTIRE puprose of starting this thread , was to :

#1 - Provoke thought about this much debated topic
#2 - Provide solutions to bring the two camps closer together
#3 - Provide proven data for solutions that work
#4 - Make a database of what subs DO work better ported than sealed

Bassfromspace and Audionutz .... You guys get it. Funny that the two who understand the importance of the potential of this thread , have such zany user names .... LOL*


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## Abmolech

Have to agree with audionutz,

May only addendum is group delay can be corrected for with electronic processing. 
Also ported, passive radiator, NLC etc have the advantage of more flexible tuning.

If you can hear the sub(s) as a distinct entity, then it is not setup right.


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## durwood

I think the 80Hz mark is hard to acheive as Mr Marv said. I must admit I don't have the technical jargon to back any of my claims up but thought I would throw it out there. I learned alot of knowledge from my installer friends, some of which have been aroud since the early 80s and have seen the changes of car audio, but some things remain the same. 

From what I learned and I noticed it from my own experimenting, a ported box plays 1 octave up and 1 octave down fromt he tuned frequency before you start to have issues whether it be frequency response or mechanical noise issues. I don't know the exact name or technical wording for it, but it something like that. For example if you tune a box at 40Hz, it should play down to 20Hz (but thereis a phase shift), and up to 80Hz. Now if you tune it to 30Hz, it SHOULD be able to play down to 15Hz and only up to 60HZ. This is where the problem lies. After 60Hz, the sub will start to sound more mechanical rather then musical. I wish I could explain that better. Anyone want to comment?

I don't know if it's possible to achieve what you want using the following, but a there is a ported enclosure you can build that has two tuned frequencies. What you do is design the box for it's correct airspace, then divide it into thirds. Figure out the port length for the entire airspace at the desired tuned frequency. The sub goes into 2/3 of the airspace and the other 1/3 is separated from the other 2/3. Then you port the 2/3 chamber, the 1/3 chammber and port it between the two chammbers, all with the same port you determined for the entire box. This will produce two tuned frequencies, one at the original desired tuned frequency and another at one octave above. So if you tuned it at 30 Hz, then it also has another tuned frequency at 60Hz. It should allow you to play up to 120Hz then. I just don't know if there is anyway to get the response flat (Maybe EQ?). It's something I have always wanted to try.


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## durwood

I'd also like to add as someone else mentioned, most SQ competion vehicles running subs in the rear probably have the subs crossed over below 60Hz if they have a 3way front stage. Once you start going over 45Hz, you run into localization problems IF your car isn't deadened enough to kill resonances. If things are vibrating you are going to be able to tell the sub is in the rear of the vehicle.


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## kyheng

Sealed vs ported, I think this topic has been discussed and argued many times in ICE forum. I can only says that there's no absolute answer for this question(too subjective arguement). This is more on personal prefrence. But fact is certain sub cannot applied on sealed enclosure(meant for SPL, Rockford's Power series) and some cannot applied on ported(never come across brand yet).
Some websites also stated that their sub is best applied on sealed XX cu value for SQ and ported YY cu for SPL. They even stated that advantages and disadvantages between them.
For my point of view, I prefer use a ported enclosure than sealed. I can always increase or decrease the gain for the sub to suit my preference.


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## backwoods

The irony is, 15 years ago, people were using sealed boxes for spl. Thinking that they could fit alot more in the area. 

Really, this thread rests squarely on the shoulders of current market trends.


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## Hillbilly SQ

i think durwood hit a lot of the nails on the head. now i'm about the do a little threadjacking so be gentle. 

my memphis hpo is STRUGGLING crossed at 40hz. in every sealed box it's been in it's a 40hz and above wonder. minimum requirement for ported is a cube. how about 1.2 tuned to 30? i mean, my midbass dominates down to about 50hz. then i get mechanical issues with bottoming out. the 24db slopes bring everything together nicely.


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## 60ndown

TEAM SHIMANO/FALCON said:


> i think durwood hit a lot of the nails on the head. now i'm about the do a little threadjacking so be gentle.
> 
> my memphis hpo is STRUGGLING *crossed at 40hz*. in every sealed box it's been in it's a 40hz and above wonder. minimum requirement for ported is a cube. how about 1.2 tuned to 30? i mean, my midbass dominates down to about 50hz. then i get mechanical issues with bottoming out. the 24db slopes bring everything together nicely.


xed @ 40? 

doesnt leave much for it to do except excurt between 40 and 30 ? no sub is gonna like that.


----------



## durwood

> I don't know if it's possible to achieve what you want using the following, but a there is a ported enclosure you can build that has two tuned frequencies. What you do is design the box for it's correct airspace, then divide it into thirds. Figure out the port length for the entire airspace at the desired tuned frequency. The sub goes into 2/3 of the airspace and the other 1/3 is separated from the other 2/3. Then you port the 2/3 chamber, the 1/3 chammber and port it between the two chammbers, all with the same port you determined for the entire box. This will produce two tuned frequencies, one at the original desired tuned frequency and another at one octave above. So if you tuned it at 30 Hz, then it also has another tuned frequency at 60Hz. It should allow you to play up to 120Hz then. I just don't know if there is anyway to get the response flat (Maybe EQ?). It's something I have always wanted to try.


Personally, i'd love to try this box out with the box tuned @~25Hz, then it could play up to 100Hz, probably with not as much peaking as tuend at 30Hz. one of the factors you have to watch out for is the FS of the sub. You need to find a sub with a lower or equal FS then what you tune it for. There are other parameters that will determine to putput of the sub/box, but if you exceed the mechanical aspects of the sub then it will sound like crap.


----------



## durwood

lukeboa said:


> xed @ 40?
> 
> doesnt leave much for it to do except excurt between 40 and 30 ? no sub is gonna like that.


Mine is crossed over @40 too. Just enough to add in what the midbasses can't do. You are right, not too many instruments are in that range, but you have to remember, it will play higher, its just down a few db in the higher bass range depending on crossover slope. I don't think you could get away with this in a 2way front stage though. Your midbass would have to do some serious work, or your tweeter would have to extend pretty low for a tweeter.


----------



## ErinH

lukeboa said:


> xed @ 40?
> 
> doesnt leave much for it to do except excurt between 40 and 30 ? no sub is gonna like that.


I was thinking that's pretty low, too.

Mine are crossed @ 63hz, and my midbass isn't really all it could be there, but I like it so it'll probably stay.



Back to the topic. 
I have no scientific evidence and only one subwoofer to base this on (since it's the only one I've had in 2+ years) but IMO, the w7 tuned very low is beautiful, but possibly not loud enough for some. There's a fine line, I've learned, but have yet to find it. Right now my music sounds good-the bass isn't overpowering- but on some songs (particularly rap music) the bass isn't as loud as I know it could be. However, with rock/pop songs the bass kicks good and is very responsive. Maybe it has more to do with music vs. synthesized beats. 

I've played around with a bunch of different designs using Box programs and it always seems that for my application to get a very flat response starting from the mid 20's you need to have at least 4 cubes and tune to around 22hz, IIRC. I'd love to do this myself but I just don't have the space. 

FWIW, here's a design I came up with when I built my last box. As stated above, I don't have this much room to work with, but I saved the design so I can maybe go back to it one day. IMHO, this is the essence of SQ in the subwoofer application.


----------



## Hillbilly SQ

durwood said:


> Mine is crossed over @40 too. Just enough to add in what the midbasses can't do. You are right, not too many instruments are in that range, but you have to remember, it will play higher, its just down a few db in the higher bass range depending on crossover slope. I don't think you could get away with this in a 2way front stage though. Your midbass would have to do some serious work, or your tweeter would have to extend pretty low for a tweeter.


i'm still rocking 2-way and my mids sound more realistic the lower they're crossed. and they keep their composure all the way up to the breakup node. my morel tweets can get down and boogie too.2khz and 3200 with 18db slopes inbetween seems to bring things together nicely on the top end.


----------



## 60ndown

bikinpunk said:


> I was thinking that's pretty low, too.
> 
> Mine are crossed @ 63hz, and my midbass isn't really all it could be there, but I like it so it'll probably stay.
> 
> 
> 
> Back to the topic.
> I have no scientific evidence and only one subwoofer to base this on (since it's the only one I've had in 2+ years) but IMO, the w7 tuned very low is beautiful, but possibly not loud enough for some. There's a fine line, I've learned, but have yet to find it. Right now my music sounds good-the bass isn't overpowering- but on some songs (particularly rap music) the bass isn't as loud as I know it could be. However, with rock/pop songs the bass kicks good and is very responsive. Maybe it has more to do with music vs. synthesized beats.
> 
> I've played around with a bunch of different designs using Box programs and it always seems that for my application to get a very flat response starting from the mid 20's you need to have at least 4 cubes and tune to around 22hz, IIRC. I'd love to do this myself but I just don't have the space.
> 
> FWIW, here's a design I came up with when I built my last box. As stated above, I don't have this much room to work with, but I saved the design so I can maybe go back to it one day. IMHO, this is the essence of SQ in the subwoofer application.


so mr punk in a bikini,

how much power you got on you w7?

i have 2500 wrms on mine and boy o boy rap and hip hop slam


----------



## durwood

TEAM SHIMANO/FALCON said:


> i'm still rocking 2-way and my mids sound more realistic the lower they're crossed. and they keep their composure all the way up to the breakup node. my morel tweets can get down and boogie too.2khz and 3200 with 18db slopes inbetween seems to bring things together nicely on the top end.


Nice. Ok so your tweets are pretty low. It's hard to find a mid that extends into the low end and also extends into the high end too. There are exceptions, but you have to find the right combo. You must have found it. Thumbs up!


----------



## ErinH

lukeboa said:


> so mr punk in a bikini,
> 
> how much power you got on you w7?
> 
> i have 2500 wrms on mine and boy o boy rap and hip hop slam


not nearly that much.  


1000 rms. Using JL 1000/1. I'd be scared to put that much on mine. The nominal rating for my 12w7 is 750. Are you running the 13 or 12?



EDIT: It's BIKIN...like Biking without the 'g'. Not bikini. I should've picked a different name years ago. No telling how many times I've had to correct someone with that. 
On a side note to that: How much of a perv would I be with a name like bikinIpunk? lol...


----------



## 60ndown

bikinpunk said:


> not nearly that much.
> 
> 
> 1000 rms. Using JL 1000/1. I'd be scared to put that much on mine. The nominal rating for my 12w7 is 750. Are you running the 13 or 12?
> 
> 
> 
> EDIT: It's BIKIN...like Biking without the 'g'. Not bikini. I should've picked a different name years ago. No telling how many times I've had to correct someone with that.
> On a side note to that: How much of a perv would I be with a name like bikinIpunk? lol...


mines a 12" and im careful with my 'nob'  
im VERY supprised your experienceing any 'shortage' of bass with a 1000/1 on your dub 7? is your elecrtical strong?

what happens when you grab your volume dial and crankit?


----------



## 60ndown

looks like jl believes the 12 w7 will survive 1500 wrms.

http://mobile.jlaudio.com/products_subs_pages.php?page_id=35


----------



## ErinH

lukeboa said:


> mines a 12" and im careful with my 'nob'
> im VERY supprised your experienceing any 'shortage' of bass with a 1000/1 on your dub 7? is your *elecrtical *strong?
> 
> what happens when you grab your volume dial and *crank it*?


Ahhh, that's the secret... when I crank it it pounds. But I have dimming due to stock electrical (other than big 3). I hardly ever put it above 23; where dimming begins. 

I suppose I should have mentioned that. If you have plenty of electrical it'll slam. I just don't do that.


----------



## ErinH

lukeboa said:


> looks like jl believes the 12 w7 will survive 1500 wrms.
> 
> http://mobile.jlaudio.com/products_subs_pages.php?page_id=35


It may survive it but 2 things:
1. The yellow is nominal. It's at 750. As you get toward 1000rms the graph turns orange-->red. I believe in between that range the item is unwarrantied. At this point warranty doesn't apply, but then I have to factor in #2...
2. I personally don't ever want to buy another sub, so I keep it at it's nominal rating. I just feel 'safer' doing this.


----------



## Hillbilly SQ

durwood said:


> Nice. Ok so your tweets are pretty low. It's hard to find a mid that extends into the low end and also extends into the high end too. There are exceptions, but you have to find the right combo. You must have found it. Thumbs up!


for a pair of mids that i intended for midbass only they do surprizingly well. i didn't expect them to sound as good as they do for midrange. i have a pair of seas w11's that are going in the kicks for midrange duty and seas neo aluminum tweets for the sails. but if the w11's don't work out like i hope, at least i know the seas tweets will drop down low enough for a useful integration with the L18's.


----------



## chad

I think the box design is application specific on MANY accounts! First off, I’m a sensitivity freak, I don’t have the electrical system in my car for that Soundstream amp setup that was recently posted for sale, and if I did it would be mine! I never will have that electrical system in this car. I need to get it done with 250W, and dealing with amplifier power all day long in many different facets of audio there is NO reason that this could not be accomplished in the hatch of “mouse-car-go” and still satisfy a rock-n-roll sound guy.

A sealed enclosure with a highish FS will work the best with the transfer function of most smaller to mid size vehicles, I understand that and am cool with it. BUT why do that? Why not build a box that is it’s most efficient in the PASSBAND you plan to work with and CUT EQ as needed to achieve that flat response if that’s what you are after. You can put a vented box that’s MUCH more efficient in a car or you can put something in that just gets it done. Even if I want to “crank up the bass” I will be applying the same amount or less power to the enclosure than I would if I had the sealed enclosure and be getting a hideous amount of low end out of the vented design, with much less (like ¼) of the power that I would to get the same level out of the sealed box. Lets face it we have a transfer function, it’s fun, and even if you are the most die-hard audiophile you WILL use it to your advantage at some point and shake your nuts, because you can! We have something at our disposal that many home audiophiles dream of, a predictable boost of low end for free! Dammit, have fun with it!

Now, If I had all the power in the world to apply to a subwoofer enclosure, and I had a driver that could take it and not go into power compression I would go sealed…. Because I could… and the box design would be easier, right, and it would protect the driver? Big deal. I can build a vented box, it does not HAVE to go to 20 cycles, I could care less about 20 cycles, there’s just not enough music content in the spectrum to have to worry about it, and even if there was…. The car’s cabin gain would more than take care of it. I’m HP’d now at 28 cycles for the record.

I’m posting the graph again, many of you will vomit if you see it again so I’ll make it clickable as to help alleviate your pain. 



White is sealed, green is vented, Dayton Reference 10HO, .66CuFt. Tuning at 30 cycles for the vented.

Yes, the sealed “Looks better” But look folks, there’s no “bump there” if you put it in a car there will be but if there also COULD be with the sealed enclosure! The sealed does not gain an advantage in sensitivity until around 22 cycles, I don’t think I have to state how much I DON’T care about those frequencies below that. If you don’t like the bump then EQ it out, the EQ DOES have a cut function, in fact it’s the only half of the EQ you should use IMHO. If you want the extra bump it’s there and it’s free.

Free power folks! A lot of big boom happens in audio where the sensitivity is increased, kick drum brunt is there, low strings on bass guitar, concert bass drums, you name it. Even the wonderful Roland 808. Lets take 40 cycles from the graph, incidentally that’s where many amps put a “bass boost” It’s almost 5dB up in the vented design!!!! When you double your power you gain 3dB, so this is, all things equal, the same increase as almost QUADRUPLING your effective amplifier power in this area of the spectrum… FOR FREE! Or better yet using ¼ of your amplifier power as you would with a sealed enclosure after EQing, I like that idea! A lot! What a concept, gaining 5dB in sensitivity where the driver will be used the most in that pass band or, looking at it this way, quadrupling your amplifier power (going to 1KW in my case) with out upgrading anything electrical, spending any money on larger amplifiers, or having a larger enclosure (mine got a bit bigger due to external venting) It cost me less than 10 dollars to gain this over a sealed box and a bit of time on WiniSD and a calculator. Not bad if you ask me.


When I go in to buy a set of pro subwoofers I don’t say “I have a big amp, show me your least efficient subs, because I have a lot of power and can afford it” Hell Noes! I say show me your MOST efficient subs that play the lowest, if it’s too much I’ll back it down. Why should car audio be any different? 

Did my SQ change when I went ported? Yep! It got better! There was no change in speed, the system wanted to play lower, I had to do some cuts. But where the BIG GLOWING improvement came into play was the higher transient ability, yes, it KIND OF got “quicker” because the amplifier had more energy on tap to supply the needed demands, the driver was excurting less, everything ran MUCH cooler and was much happier. So in theory, if done right, a properly designed vented enclosure will be LESS sloppy than a sealed running balls to the walls, amp clips less, driver is in the magnetic field more, everything is happier making the same amount of output as a sealed enclosure would.

I challenge you all when buying a sub to build a test box, most will build the “right” box first then tune away, well, tuning can be done in a mechanical standpoint too. So many laser-aim their pods but forget to take a few days to experiment with enclosure design. Build one that’s too big and add wood inside, port it, seal the ports, play with volume again. Wood and PVC are cheap. The problem with vented enclosures is that people think a hole in a box with some tube vents it, that’s wrong. It’s a SYSTEM, venting has to do with the driver, the box, the area of the vent, all this. That’s why they are harder to build and why there are so many ****ty sounding ones out there. Take your time and do it right and you may just be surprised!

Chad


----------



## 60ndown

bikinpunk said:


> 2. I personally don't ever want to buy another sub



 ya oooooooooooooook.


----------



## ErinH

lukeboa said:


> ya oooooooooooooook.


Subwoofers are expensive, mang!


----------



## 60ndown

chad said:


> Did my SQ change when I went ported? Yep! It got better! There was no change in speed, the system wanted to play lower, I had to do some cuts. But where the BIG GLOWING improvement came into play was the higher transient ability, yes, it KIND OF got “quicker” because the amplifier had more energy on tap to supply the needed demands, the driver was excurting less, everything ran MUCH cooler and was much happier. Chad


the universe is amazing, im repeating my self but , i have had exactly this^ experience in the last 10 days.

i have always run sealed looking for sq, but 10 days ago instaled a 6.5 cubes @35 CRX in my mini van.

everything chad mentions above is true in my experience.


----------



## 60ndown

bikinpunk said:


> Subwoofers are expensive, mang!


i paid $250 for my 12 w7 used.


----------



## durwood

Kudos Chad. I agree 200%. If I wanted to give up more room in my trunk I would go back to vented in a heartbeat. I can't tell you how many boxes I built just as your described with all the experimenting. I filled our garage with them when I was younger and pissed off my parents. I hated sealed until I found the W6V2, but I still wish to go back to my vented days and get rid of the boring sealed box. I actually tried so hard to find a sub that could sound like my old beta 10's vented but in a sealed box.


----------



## Mr Marv

audionutz said:


> Hello gang!
> 
> Shall we discuss specifics here, or what?
> 
> Also, what is with the requirement to play a subwoofer up to 80Hz? If we are discussing customers cars off the street who want a good sounding street system, then this topic is not what I thought it was. If we are discussing the uppermost pinnacle of Sound Q utopia, then I argue that in a properly designed system, the front stage should be the dominant factor, and the subwoofer is simply to reinforce the midbass and bottom octaves, NOT to be the primary source of these notes. STRONG midbass presence in the vehicle will be there with a properly-designed and tuned SQ system, and unless the sub is mounted up front, you should never run a sub above roughly 60Hz.
> So, do we need some clarification here as to what is expected of this thread?
> 
> 
> Sorry for the rambling, its late, and my brain is toast LOL!


*""Also, what is with the requirement to play a subwoofer up to 80Hz? If we are discussing customers cars off the street who want a good sounding street system, then this topic is not what I thought it was.""*

I'm not sure I know what the topic was now myself   and guess maybe I "assumed" some things  

I knew AVI had a shop and figured he was referring to his "typical customer" based on his first post concerning the "80hz down part". I was under the impression he was coming from the standpoint that a lot of people don't have adequate midbass (for reasons he stated afterwards) and that sealed was "best" where people use a "sub" woofer more as a combination "woofer"/"sub woofer" (I noticed this is the case with a LOT of systems I listen to). I also think (again based on what he posted) that he has people saying things like "such and such sub in a ported enclosure will trounce all over the sealed enclosure and sound better etc" when they have _no foundation_ (ie: "experience") for their claims other than "what they read or heard from someone else". I do not have the experience that you [audionutz] have with "older drivers" but I've had tons of experience with "newer" ones as well as experimented with NUMEROUS designs and have yet to come across one that works "all around" as well in ported as it does in sealed (again based on the 80hz down situation). Obviously I have not tried every sub/enclosure design out there and was not saying that ported enclosure designs/subs that play well from 80hz down don't exist rather *I* have not come across them. In any case I always felt that some current sub manufacturers "fudge" things a bit with enclosure specifications as well as leading people to believe that their subs will work great in _ALL_ applications.
I'll holler at you soon Steve as I would sure like to know of a sub and ported enclosure design that will work 80hz down so I can build it and try it myself


----------



## backwoods

only time I do sealed is for space saving. 

I build alot of home towers for people as well as doing car audio. I'd be willing to bet that over 80% of my home tower designs are vented. 

I love me a good port. 

A correctly ported midrange can sound so effortless and light


----------



## chad

durwood said:


> Kudos Chad. I agree 200%. If I wanted to give up more room in my trunk I would go back to vented in a heartbeat. I can't tell you how many boxes I built just as your described with all the experimenting. I filled our garage with them when I was younger and pissed off my parents. I hated sealed until I found the W6V2, but I still wish to go back to my vented days and get rid of the boring sealed box. I actually tried so hard to find a sub that could sound like my old beta 10's vented but in a sealed box.


The graph posted is the same box... Only with venting added. .66CuFt, not large by any means IMHO.

Chad


----------



## durwood

chad said:


> The graph posted is the same box... Only with venting added. .66CuFt, not large by any means IMHO.
> 
> Chad


I missed that. Interesting.....66ft3 total including port displacement? My 10W6V2 is in a .7 right now sealed. I might actually consider cutting a hole in it and try that. then I could change some wiring and bump up the wattage to my midbasses


----------



## chad

durwood said:


> I missed that. Interesting.....66ft3 total including port displacement? My 10W6V2 is in a .7 right now sealed. I might actually consider cutting a hole in it and try that. then I could change some wiring and bump up the wattage to my midbasses


Nope, unfortunately I had to put the ports outside... and it's UGLY!. I just wanted to see what it would do. It's not the fer-sure enclosure, that is coming along as we speak with fiberglass and space in the spare tire area.

I'v been rolling a "test enclousre" for 1.5 years now :blush: 

Chad


----------



## Mr Marv

The original topic (as I understood it  ) was "ported sub enclosure design that can play as well as sealed from *80hz down*" but it looks like it turned into more of a "what type of enclosure do you prefer" type of thread"  In any case I'd like to hear more comments based on actual experiences with the differences they found like Chad and others did. I'd also be curious to hear comments from anyone who has built a sealed enclosure and a ported enclosure for the same sub _that played 80hz down_ equally well either way (sans output) or had subjectively "better SQ" in the ported (BTW, when I speak of SQ I'm speaking of "accuracy") . Also, if someone can hip me to a sub and a starting point for an enclosure design that does this I may buy one and do a little more experimenting myself when I have time.


----------



## legend94

300Z said:


> IMHO I think it's a lot driver dependent. most of these drivers aren't specifically designed for ported boxes. With that said there are very few sealed subs I would take over a ported old school GTi.



mmm

my thoughts exactly, but they dont sound to shaby in a sealed box either 

im hoping to send one to npdang for testing within 2-3 weeks


----------



## 300Z

legend94 said:


> im hoping to send one to npdang for testing within 2-3 weeks


You gonna send the 1200GTi or a 1500GTi?


----------



## durwood

chad said:


> Nope, unfortunately I had to put the ports outside... and it's UGLY!. I just wanted to see what it would do. It's not the fer-sure enclosure, that is coming along as we speak with fiberglass and space in the spare tire area.
> 
> I'v been rolling a "test enclousre" for 1.5 years now :blush:
> 
> Chad


Damn! I was hoping but I figured it was too good to be true. I would have to do the same to my box then and I custom built it to fit so it's not jsut some plain old box I could esily modify. 

Hey I'm running some "test" tweeter pods that have been in my ride for almost 3 years. :blush: x2 I slapped some paint on them just to make them look almost like they should be there.


----------



## demon2091tb

Hehe this may be a devil's advocate post as well, but neway.

A few yrs ago i had an explorer, had a pair of Rockford HE2's in 2.2cf/side so 4.4 -5cf total b/w the two, ported at 32hz i beleive it was (i had no experience at the time, so had a local DJ build it for me.)

Neway i loved the sound of it, granted it only got loud, and there was almost NO SQ to it at all, plugged all 4 ports, 2 per side, and the sound automatically improved, better midbass integration with given xover points (amp), and had a very nice low end, (didn't have the 40-60hz hump that gave it the LOUD feel). Anyway i ended up leaving it sealed in the oversized enclosures for the remainder of the time i had them, i just liked the sound that much better.

Now granted i didn't build the box, and had no input in the design, but it improved 10fold in SQ over the ported design.

Another situation, granted it isint applicable to a car, but given my Tempest in a 7cf ported enclosure tuned at 21hz in my HT, and using one in my car at 4.2cf sealed, i prefered the ported design just from a SQ standpoint. When i did have my tempest in my car i had no EQ at the time, so a 60-80hz huge peak gave me alot of problem, but down low it was the most effortless bass i've had or heard in a car to date (with limited experience on sub and listening), but my DIYMA comes very close. I went with the Diyma sealed because of space restrictions but from a SQ standpoint with faraday rings, etc the Diyma sounds ALOT better, but with less cone area, etc its very effortless, just dosent seem to have the dynamic ability that the Tempest did have.

But this is all based on my experience and the few things i've used over the last few years...........Without any EQ. Though i have all that on hand now, so it honestly could change ALOT.

My .02


----------



## Whiterabbit

AVI, would you still be so confident in your responses if we removed the requirement of 80 and down? seems like a HUGE range to me for a ported box to play uniformly across its range (assuming our goal is to reach the bottom octave) with no sonic problems whatsoever......

I dunno, it almost seems like that was a necessary condition added for the sole reason of being able to claim difinitively that ported boxes will demonstrate inferior performance?

If we change our testing conditions to something "less universal", I think its likely we could show (qualitatively, of course) that ported boxes could perform jsut as well as a sealed box.


----------



## JAG

Wow ... I can see the 80hz x-over point really rubbed some dirt in a wound  But let's face reality guys ..... *I did indeed say , as well as mean 80hz and down.*

So , one last time .... Here is exactly why :

Most of my customers run 2-way systems. Most of those systems consist of a 6.5" mid-bass driver in the doors. Most of those 6.5" drivers get played LOUDER THAN RAW HELL ..... Most of those 6.5" mid-bass drivers can NOT play that loud when crossed over much lower than 80hz. *Therefore , considering ALL of this , I NEED to build subwoofers that play from 80 hz and down !!!!!!!!!!!!!!!* For every customer with dedicated , large mid-bass drivers in 3-way systems , that have multiple amp set ups , and are DIY minded , I have 100 customers that are NOT fitting this mold !!!!!!!!!!

Now , for the perfect example : This customer I'm struggling to make happy with his sub system , has chosen Rainbow Profi Kicks for his car ... They can NOT be crossed any lower than 80hz at 12db octave. This is due to how they are designed .... SOOOOOO , he needs a sub to play from 80hz and down. 

Let's get one thing clear .... I have NO agenda with this post , to try and prove that sealed sounds better than ported ... ONLY my opinion !!!

*And to prove it , I'll isuue everyone on here a challenge :*

I have two subs that I am going to demo for this customer this week ... One is a JBL w12GTi , and the other is an Oz Audio Matrix Elite 15 ....

So , post up a design of a ported enclosure for EACH of these two subs on this thread.... Then agree between yourselves which design is best , and I WILL BUILD THAT ENCLOSURE and have my customer listen to it , *WITHOUT him knowing he is listening to a ported enclosure*    
*I'll record his opinion , as well as the rest of my employees opinions , and post them up here.* How does that sound ? Pretty fair I would think


----------



## audionutz

Chad, great post man. Efficiency is something that must be mentioned here, and this term has of late become lost as woofers with "super-high power handling" are the norm now, and most people, especially installers, tend to take the easy approach and either buy a prefab sealed or build the simpler sealed designs for most of their customers rather than taking the extra effort to build a proper ported design. And we all know what woofers work best in smallish sealed boxes, dont we? yes we do! And their efficiency specs are mediocre at very best. It is hard for the layperson to understand how proper transient response and dynamics should "feel", and it's very hard for a sealed enclosure imho to reach this level when compared to a high efficiency ported design....more in a bit 

Marv, if you want I will send you a sub to test along with box specs and whatnot that should have a passband of about 23Hz to 110Hz within a +/- 3dB window with little or no EQ...interested?


Oh, and while we are on the subject...why do some of you feel that a ported woofer cant play from subsonic to above 80Hz ??? Is this some off-the-wall range someone made up, or have your personal experiences told you so? Either way, this is a very sad misconception. Some Pro Sound woofers can play as high as 2.5K or higher in ported enclosures, albeit the bottom octave is usually pretty thin using these drivers. Most home audio speaker systems use on board passives to play the sub up however high it needs to to meet the mid, and they are both ported and sealed...arent they? Yes they are. Hell, some home speakers play the bass driver up to 500 Hz or higher , esp when dome mids are used. These are ported, yet there is nothing "odd" or Unnatural about their sound. 
Am I missing something here?


----------



## 60ndown

perhaps explaining to customers that the gap between a 6.5 and a 10 or 12 is big, and that unless they are willing to install dedicated midbass they must accept some anomalies in the 'blending' of mids and sub?

they wouldnt expect 0-60 in under 5 seconds without correct 'set up' would they.


----------



## 60ndown

what vehicle this box going into? max dimensions we can use?



amp?


----------



## chad

legend94 said:


> mmm
> 
> my thoughts exactly, but they dont sound to shaby in a sealed box either
> 
> QUOTE]
> 
> 
> But the pulp dust dome can't take the pressure for some reason. Shreds them. JBL pro deritaves don't like sealed enclosures.


----------



## 300Z

The WGTi is designed primarily for sealed boxes, it will work fine in a ported box and will play as high as you need it to go but the low end will be excessive and will give the impression that the sub can't play the higher freq as well, you will need to EQ down the lower freq to achieve a flat response. But the all the potential is there.


----------



## audionutz

AVI, just read your latest, now I understand 
YOu are 100% correct as a shop owner installing for Joe Public, 80Hz is the norm when no meaty midbasses are present. I mean hell, Joe Public just wants his **** to slam, right? He doesnt care about a possible frequency gap, and 75% of the customers would be happy with the sub playing up to 80Hz and the mids coming in at 150Hz, creating an Underlap of frequencies but increasing midrange clarity exponentially.

Regarding your customer, I can vouch for the GTi12 in the "built to factory spec" ported enclosure as being able to cover your entire freq range with authority, dynamics, clarity, proper LFE, and great loudness/efficiency! In fact, I am so confident that you both will love the sub in that enclosure, that I'd be willing to place a bet....if you'd like


----------



## JAG

lukeboa said:


> what vehicle this box going into? max dimensions we can use?
> 
> 
> 
> amp?


Enclosure can NOT be over 3 cu ft ..... I can re-design the outer dimensions , while keeping the volume and port size the same , if the trunk requires it.


----------



## JAG

audionutz said:


> AVI, just read your latest, now I understand
> YOu are 100% correct as a shop owner installing for Joe Public, 80Hz is the norm when no meaty midbasses are present. I mean hell, Joe Public just wants his **** to slam, right? He doesnt care about a possible frequency gap, and 75% of the customers would be happy with the sub playing up to 80Hz and the mids coming in at 150Hz, creating an Underlap of frequencies but increasing midrange clarity exponentially.
> 
> Regarding your customer, I can vouch for the GTi12 in the "built to factory spec" ported enclosure as being able to cover your entire freq range with authority, dynamics, clarity, proper LFE, and great loudness/efficiency! In fact, I am so confident that you both will love the sub in that enclosure, that I'd be willing to place a bet....if you'd like


He he he .... How will you guys EVER agree ? LOL
Read 300Z's remarks about the JBL in the post directly above yours !

As far as my customers not having a problem with underlap , to create better clarity .... That won't work , and here's why : They first listen to my car , and the insanely strong mid-bass that I have , and they WANT IT !!! LOL Maybe I should not let them listen to my car , huh ? LOL


----------



## solacedagony

Chad: What equalization do you have that goes all the way down to 20hz?


----------



## chad

300Z said:


> The WGTi is designed primarily for sealed boxes, it will work fine in a ported box and will play as high as you need it to go but the low end will be excessive and will give the impression that the sub can't play the higher freq as well, you will need to EQ down the lower freq to achieve a flat response. But the all the potential is there.


I thought you were referring to the original VGC based GTi series. JBL says Oh Noes.


----------



## chad

solacedagony said:


> Chad: What equalization do you have that goes all the way down to 20hz?



Don't need to go that low, I have a subsonic filter with the anchor set at 28Hz, then the alpine takes care of things from there with wide slopes. I also think the Alpine will EQ that low but I can't remember, it's been a while.

Chad


----------



## audionutz

Correct! Or fire your salesperson for not selling the customers what they want----nice, meaty midbasses 

300Z is mistaken, as the GTi is a meatier version of the vintage JBL prosound drivers, but re-engineered to handle higher excursion with beefier cones, and consequently CAN be used in sealed boxes. But, as others pointed out, they are power-limited in sealed.

I run a pair of Gti12s ported out back, built to spec, and they are very impressive. I run a pair of Gti10s in a sealed isobaric up front as sub-reinforcement for the SQ competition system. I did a large write-up about the isobaric enclosure on ECA, and in a nutshell, each sub gets a low dose of power, roughly 250W max each, and the added cone mass of the Isobaric loading helps me gain LFE on the bottom end, but the two motor structures keeps the cones nice and controlled. The enclosure is .5 cubes sealed! If I had 1.75 of space up front, I would have done a single driver ported.


----------



## 300Z

300Z said:


> IMHO I think it's a lot driver dependent. most of these drivers aren't specifically designed for ported boxes. With that said there are very few sealed subs I would take over a ported old school GTi.





300Z said:


> The WGTi is designed primarily for sealed boxes, it will work fine in a ported box and will play as high as you need it to go but the low end will be excessive and will give the impression that the sub can't play the higher freq as well, you will need to EQ down the lower freq to achieve a flat response. But the all the potential is there.





chad said:


> I thought you were referring to the original VGC based GTi series. JBL says Oh Noes.


My first post was regarding the original GTi with the VGC and the second was regarding the new *W*GTi...


----------



## chad

300Z said:


> My first post was regarding the original GTi with the VGC and the second was regarding the new *W*GTi...


Ahhhhhh, I see now. Damn ADD.


----------



## 300Z

audionutz said:


> 300Z is mistaken, as the GTi is a meatier version of the vintage JBL prosound drivers, but re-engineered to handle higher excursion with beefier cones, and consequently CAN be used in sealed boxes. But, as others pointed out, they are power-limited in sealed.


Which version of the GTi are we talking about new or the old school? If the later, I would never consider running them sealed IMHO.



audionutz said:


> I run a pair of Gti12s ported out back, built to spec, and they are very impressive.


Did you ever measured the FR on those running up to 80hz?


----------



## chad

audionutz said:


> 300Z is mistaken, as the GTi is a meatier version of the vintage JBL prosound drivers, but re-engineered to handle higher excursion with beefier cones, and consequently CAN be used in sealed boxes. But, as others pointed out, they are power-limited in sealed.


The GTi series has the EXACT same motor as the pro variant of the "G" designation (4 ohm) Not meatier, just a heavier cone, same dust dome, that, incedentally, comes apart in sealed enclosures and poorly designed vented ones. JBL does not recommend a sealed allignment for this unit, they are aprehensive about bandpass.

Chad


----------



## durwood

audionutz said:


> Oh, and while we are on the subject...why do some of you feel that a ported woofer cant play from subsonic to above 80Hz ??? Is this some off-the-wall range someone made up, or have your personal experiences told you so? Either way, this is a very sad misconception. Some Pro Sound woofers can play as high as 2.5K or higher in ported enclosures, albeit the bottom octave is usually pretty thin using these drivers. Most home audio speaker systems use on board passives to play the sub up however high it needs to to meet the mid, and they are both ported and sealed...arent they? Yes they are. Hell, some home speakers play the bass driver up to 500 Hz or higher , esp when dome mids are used. These are ported, yet there is nothing "odd" or Unnatural about their sound.
> Am I missing something here?


I would agree with you on home and Pro, but we are talking a subwoofer in a car where there is cabin gain and resonant frequencies that amplify things greater than what you woudl ever see in a home or Pro application. Sure if you EQ it you could probably get it to sound ok, but from my experiences it's insanely boomy up there and unless you have a serious EQ that can make drastic cuts, I still stick to my statements I made. I have experienced it on more than one occasion. It all depends on the car though too.


----------



## JayBee

audionutz said:


> Correct! Or fire your salesperson for not selling the customers what they want----nice, meaty midbasses



we have a winner!

i really like my current midbass set-up (it'll snap your pants leg) but i'm experimenting this summer with some other stuff (ID, AA), but it seems like locally no shops really try to sell midbass as a component in an audio set-up. I guess it isn't as sexy as subs, but it makes a much bigger inpact in performance IMHO.


----------



## audionutz

300Z said:


> Did you ever measured the FR on those running up to 80hz?


Yes, I did, and I do run them to 80Hz and they are "on" for both RTA and SPL testing in competition, routinely scoring 25-26 out of 30 points possible on RTA and routinely hit the 135dB spl cap with this eq setting. IIRC, my teams' two Dodge Rams running ported GTi subs were a couple of the ONLY cars at last year's Finals event to reach SPL cap and score high in RTA too.

But thats neither here no there...point is, the GTO and Power series JBL subs in the current lineup are the ones designed for sealed enclosures. The GTi is an "ideally-ported" woofer, that happens to work well sealed too.


----------



## JAG

Wow .... Lots of confusion about the new version of the GTi subs ....

First off , the JBL website directly states the new subs are MEANT to be used in small sealed or ported enclosures. 

Werewolf has some experience with them , and has suggested I place the JBL in a large sealed box , and take up air-space if needed. 

Here's JBL's link , and it has ALL of the info a person would EVER need , including the Theile Small parameters , and enclosure reccomendations .... However , I SERIOUSLY doubt the 1cu ft sealed enclosure that JBL reccomends for this driver is anywhere close to being a good idea.

http://www.jbl.com/car/products/product_detail.aspx?prod=W12GTI&ser=GTI&cat=SUB

You guys take a look at this link , and stop guessing at what MAY be best ... let's hear your reccomendations AFTER you look at all of the specs ..


----------



## JAG

Here's the link for the Oz audio sub ... It also has specs that you guys can use ...

http://www.ozaudio.com/pages/ME15.html


----------



## legend94

300Z said:


> You gonna send the 1200GTi or a 1500GTi?


im going to send the 1200GTi as long as he will go easy on it  is this test just for measuring or is it subjective as well? i know he will take good care of it.


----------



## JAG

The amp he's running is an Arc Audio 2300SE .... 1400 watts at 4ohms mono ..

The JBL is a dual 6ohm vc , and the Oz is a dual 2ohm vc ...


----------



## legend94

chad said:


> The GTi series has the EXACT same motor as the pro variant of the "G" designation (4 ohm) Not meatier, just a heavier cone, same dust dome, that, incedentally, comes apart in sealed enclosures and poorly designed vented ones. JBL does not recommend a sealed allignment for this unit, they are aprehensive about bandpass.
> 
> Chad


Im using mine in a sealed box and have been for over a year without any problems. It did get louder of in the vented box with nearly the same level of SQ  In the manual it says the sealed box requirements are 1.35 cuft with 1 inch fiberglass or fiberfill around all sides. IIRC without the fill around the outside the box can be 1.8 ft. Im in the process of building a 1.8 box, so if i dont like it I can always put a RSD in it


----------



## JAG

legend94 said:


> Im using mine in a sealed box and have been for over a year without any problems. It did get louder of in the vented box with nearly the same level of SQ  In the manual it says the sealed box requirements are 1.35 cuft with 1 inch fiberglass or fiberfill around all sides. IIRC without the fill around the outside the box can be 1.8 ft. Im in the process of building a 1.8 box, so if i dont like it I can always put a RSD in it


Are we talking about the same exact JBL sub here ? Check the link I provided , and you'll see the manual calls for a 2.25 cu ft box , with a 4" port that is 13.31" in length ....

If we're talking about a different sub , can we please stay on topic. If people actually _*DO*_ provide a design for what they think will be _*THE*_ ultimate ported enclosure for these woofers , and this *DOES* prove to be true after listening to it ..... Then a LOT of myths can be put to rest , huh ?


----------



## audionutz

AVI, I stand by my experience with this EXACT same driver, the ported enclosure in the spec sheet is exactly the one I built but with a couple added tricks. When will u be constructing?


----------



## JAG

audionutz said:


> AVI, I stand by my experience with this EXACT same driver, the ported enclosure in the spec sheet is exactly the one I built but with a couple added tricks. When will u be constructing?


Very interesting good man .... I'll be building these enclosures starting tomorrow afternoon ... so , any tricks you think should be added , you'll need to let me know soon. I'll be building a 2.5 cu ft sealed for the JBL , and I guess the ported one spec'd by JBL ....

I must say though , I think it's kind of funny how so many people get on here and defend ported enclosures with a fury .... but then I issue the challenge , and where are they now ? I mean , if I was all that interested in proving a point , I think I would have plugged those drivers into a program , and posted up.

The single biggest challenge with these two particular subs , is finding ANYONE who has much first hand experience with them. I tried searching for reviews on that Oz driver , and can't find really anything at all. I know the 1.75 cu ft that is reccomended for it , seems awfully small for a 15".


----------



## chad

What challenge was issued... I missed it in the hubbub ala JBL, dialup prevents parusing sometimes


----------



## legend94

AVI said:


> Are we talking about the same exact JBL sub here ? Check the link I provided , and you'll see the manual calls for a 2.25 cu ft box , with a 4" port that is 13.31" in length ....
> 
> If we're talking about a different sub , can we please stay on topic. If people actually _*DO*_ provide a design for what they think will be _*THE*_ ultimate ported enclosure for these woofers , and this *DOES* prove to be true after listening to it ..... Then a LOT of myths can be put to rest , huh ?



no we are not talking of the same sub. however, someone did bring up the old school GTi (which is the GTi1200 & GTi1500) on the second page of this massive thread and i commented on it to them. sorry to jack your thread if thats what you think....so back to topic and ill stay out of this thread...


----------



## chad

That's the GTi I was talkng about too....

Returns to corner
Chad


----------



## audionutz

OK sir, heres what I wantcha to do...
#1- build it with a square port instead of round, and use a roundover router bit to round off the internal port edges on both the inner and outer port openings.
#2- Place internal braces inside the enclosure to help secure the baffle and backwall, also the top and bottom. Rigidity is the KEY!
#3- STretch a chunk of pantyhose over the port opening that will be in the box, and staple the pantyhose securely and very tightly. This seems odd, but it will do two things- first, it is a form of resistive damping (the topic of another thread) Second, it will hold in the polyfill from step 5 so it does not blow out of the port.
#4- Use 3" fiberglass insulation, cut it into panels, and line the inside of the box as directed in the specs. Staples or spray glue work great for this.
#5- Loosely fill the ENTIRE remainder of the enclosure with polyfill... dont cram a ****load in, fluff it up LOOSELY but make sure it fills the inside of the box. THis also pertains to the resistive damping.

If your car is a sedan or coupe with a trunk, fire the sub backward from behind the rear seat into the trunk. If its a hatch, you can fire it upward or back, but you'll need to test which sounds better.

Do this, and ye shall believe


----------



## azngotskills

Does this apply to only the JBL in the thread


----------



## JAG

audionutz said:


> OK sir, heres what I wantcha to do...
> #1- build it with a square port instead of round, and use a roundover router bit to round off the internal port edges on both the inner and outer port openings.
> #2- Place internal braces inside the enclosure to help secure the baffle and backwall, also the top and bottom. Rigidity is the KEY!
> #3- STretch a chunk of pantyhose over the port opening that will be in the box, and staple the pantyhose securely and very tightly. This seems odd, but it will do two things- first, it is a form of resistive damping (the topic of another thread) Second, it will hold in the polyfill from step 5 so it does not blow out of the port.
> #4- Use 3" fiberglass insulation, cut it into panels, and line the inside of the box as directed in the specs. Staples or spray glue work great for this.
> #5- Loosely fill the ENTIRE remainder of the enclosure with polyfill... dont cram a ****load in, fluff it up LOOSELY but make sure it fills the inside of the box. THis also pertains to the resistive damping.
> 
> If your car is a sedan or coupe with a trunk, fire the sub backward from behind the rear seat into the trunk. If its a hatch, you can fire it upward or back, but you'll need to test which sounds better.
> 
> Do this, and ye shall believe


Ugh .... OK .... but you do know this will make the sub actually act like it is in a larger enclosure , and that will change the tuning somewhat ...
The square port design will take more room ..... I'll have to see just how I can accomplish this , and still make the sub fit into the car.
Want the box to be 2.25 cu ft before the square port is added , or after ? Cause the material ( MDF ) for the square port , is going to take up more displacement than a round port will ....


----------



## JAG

legend94 said:


> no we are not talking of the same sub. however, someone did bring up the old school GTi (which is the GTi1200 & GTi1500) on the second page of this massive thread and i commented on it to them. sorry to jack your thread if thats what you think....so back to topic and ill stay out of this thread...


No man .... It's not like that .... I just need to be able to keep things straight here , where I don't build something that is NOT for the driver I have ... LOL


----------



## JAG

azngotskills said:


> Does this apply to only the JBL in the thread


Nope .... I said i'd build a ported design for the Elite Matrix 15" too , IF someone submits a design they say will play up to 80 as well as a sealed will ...


----------



## audionutz

AVI said:


> Ugh .... OK .... but you do know this will make the sub actually act like it is in a larger enclosure , and that will change the tuning somewhat ...
> The square port design will take more room ..... I'll have to see just how I can accomplish this , and still make the sub fit into the car.
> Want the box to be 2.25 cu ft before the square port is added , or after ? Cause the material ( MDF ) for the square port , is going to take up more displacement than a round port will ....


No, that applies only to an enclosure of finite airspace, (sealed). Just trust me,,,,the added damping will help to smooth the response peak at 40-45Hz. 

The enclosure needs to be 2.25 NET internal, so you must account for driver and port displacement, adding them into the volume as well.


----------



## 60ndown

my current ported box sounds as good as anything i have ever heard.

the guy that designd that box also designd this box for my 12w7 

for me to work in my mini van.

i have no idea what its tuned to or size (you do the math)

but im going to offer that the jbl will work in this box if someone can calc the

dimensions and get them into your customers vehicle.

im assumeing/guessing that the 12w7 and the 12" jbl sub were talking bout 

here are close enough in ts params to use the same box

but im guessing, if one of you wants to do the calcs.

my point is that the guy that designd this box did a great job on my other 

box.


----------



## 60ndown

audio nuts,

is lineing a ported enclosure with fibreglass and a stocking to keep it in 

always a good idea.


shall i?


only take 15 minuets to try i spose?

do you have any spare stockings?


----------



## chad

lukeboa said:


> my current ported box sounds as good as anything i have ever heard.
> 
> the guy that designd that box also designd this box for my 12w7
> 
> for me to work in my mini van.
> 
> i have no idea what its tuned to or size (you do the math)
> 
> but im going to offer that the jbl will work in this box if someone can calc the
> 
> dimensions and get them into your customers vehicle.
> 
> im assumeing/guessing that the 12w7 and the 12" jbl sub were talking bout
> 
> here are close enough in ts params to use the same box
> 
> but im guessing, if one of you wants to do the calcs.
> 
> my point is that the guy that designd this box did a great job on my other
> 
> box.


THAT is the largest misconception in vented boxes. Driver parameters play a very important role. One driver may have a flattish response while the other driver in the same box may have an enormous hump somewhere in the response plot.

This is why you can't just go buy a vented thump-box at a chain store, slap any woofer that says it will work in a vented box and expect predictable results.

Box design for vented boxes is VERY important and must be designed specifically for the intended driver, if not it's pot-luck.

Chad


----------



## 60ndown

chad said:


> THAT is the largest misconception in vented boxes. Driver parameters play a very important role. One driver may have a flattish response while the other driver in the same box may have an enormous hump somewhere in the response plot.
> 
> This is why you can't just go buy a vented thump-box at a chain store, slap any woofer that says it will work in a vented box and expect predictable results.
> 
> Box design for vented boxes is VERY important and must be designed specifically for the intended driver, if not it's pot-luck.
> 
> Chad


  i love pot lucks !


----------



## 60ndown

after my ported experience the last 10 days,

i would love to understand designing a good ported box, but my a.d.d. makes

it almost impossible for me to study anything.

can any of you give me a good AND SIMPLE idea of how to design a good 

ported box please. wave propagation etc etc.

i really want to know but dont want to have to wade thru the 

WHOLE INTERNET

to understand, 

please, if anyone can pm or post some good easy pages full of ported 

design imfo i will have sex with you. 









































(i'll be daddy  )


----------



## chad

Do you have WinISD? It's free and plugging and chugging different drivers or your own hypothetical drivers you make up will teach you A LOT!

You will learn what the difference in parameters will do in the real world (well anechoic)


----------



## 60ndown

chad said:


> Do you have WinISD? It's free and plugging and chugging different drivers or your own hypothetical drivers you make up will teach you A LOT!
> 
> You will learn what the difference in parameters will do in the real world (well anechoic)


i forgot to mention im also [email protected] at computers, and ive read more than 1ce that box design programs are not accurate or any good at all?

but waddaiknow? 

how about 15 lines of hand typed essential basic facts about ported box design?


_*PLEASE*_


----------



## chad

lukeboa said:


> i forgot to mention im also [email protected] at computers, and ive read more than 1ce that box design programs are not accurate or any good at all?
> 
> but waddaiknow?
> 
> how about 15 lines of hand typed essential basic facts about ported box design?
> 
> 
> _*PLEASE*_


Entire books are written on that topic and just touch on it  

Box design programs are NOT accurate at predicting in-car response, but quite accurate for providing anechoic data. After the anechoic data is derived you can measure your transfer function and apply that to the anechoic plot.

*Anechoic=free feild, no reflections, no loading.

Chad


----------



## solacedagony

chad said:


> You will learn what the difference in parameters will do in the real world (well *anechoic*)


Keyword there Luke. Anechoic. That doesn't factor in room gain, reflections or any of that other junk. So if you have a transfer function of the room or car you're putting the box in, you basically have your response in front of you.
Playing with WinISD for awhile shows you how tuning, box volume and driver parameters effect response.

Edit: Awww, Chad beat me


----------



## audionutz

Luke, 
regarding the lining of a ported enclosure with insulation, 
I personally will always do this for an SQ application, but for a customer who simply wants bang for the buck or "street bass", it is of little importance and sometimes smooths out the huge "bump in response" a little too much, defeating some of the added gain that bassheadz love.

Lining a ported enclosure helps to absorb standing waves within the box, thus damping cabinet resonace that can occur and can possible be audible emanating from the port (thus, it also helps control port noises to some degree). This technique also helps to dampen the system a bit, and helps take the "boominess" out of the enclosure if any were to occur.

The stockings thing I mentioned was not for this insulation....it was for the POLYFILL that AVI is going to use also in the enclosure, plus will help to add some "resistance" to the collumn of air moving back and forth in the port tube.
Get it?


----------



## Mr Marv

audionutz said:


> Luke,
> regarding the lining of a ported enclosure with insulation,
> I personally will always do this for an SQ application, but for a customer who simply wants bang for the buck or "street bass", it is of little importance and sometimes smooths out the huge "bump in response" a little too much, defeating some of the added gain that bassheadz love.
> 
> Lining a ported enclosure helps to absorb standing waves within the box, thus damping cabinet resonace that can occur and can possible be audible emanating from the port (thus, it also helps control port noises to some degree). This technique also helps to dampen the system a bit, and helps take the "boominess" out of the enclosure if any were to occur.
> 
> The stockings thing I mentioned was not for this insulation....it was for the POLYFILL that AVI is going to use also in the enclosure, plus will help to add some "resistance" to the collumn of air moving back and forth in the port tube.
> Get it?


He really does have A.D.D. as he mentioned (you'll see at the BBQ ) but I'll call and explain it to him 

I'll give you a holler later today Steve when I get back from the hospital.


----------



## chad

audionutz said:


> Lining a ported enclosure helps to absorb standing waves within the box, thus damping cabinet resonace that can occur and can possible be audible emanating from the port (thus, it also helps control port noises to some degree).


You MAY want to re-word that. A sub enclosure probably will not have a standing wave when used for a subwoofer application, it's too small. If it wasn't then the standing wave would not eminate from the port since it's tuned, it would interact with the driver itself. It's even rough getting a standing wave in a car from a sub, hence the transfer function that depicts the point at which the environment goes from modal to pressure.

For a sub enclosure to have a standing wave at, say 100 cycles one of it's dimensions would have to be 11.3Ft.

http://www.mcsquared.com/wavelength.htm

Chad


----------



## durwood

so is it worth it lining or stuffing a ported box IYO? I have never had good results with doing that. I just sprayed the inside with rubber undercoating and called it a day instead.


----------



## chad

I line or stuff mine For the tiny car box it did not make a difference, but it is TINY! My pro boxes always get it because you never know what kind of duty they may be pressed into in an "oh ****" moment.


----------



## durwood

Ya I was referring to it more in a car situation. For home and pro I could definitely see it being useful.


----------



## MIAaron

Chad, you only need a 1/4 wave for it to propagate. That's why most cars have a bump in the 40-50hz range...the distance from sub to the dash is usually in the 5-7ft area.

I agree with you on the standing waves in a sub box though.


----------



## SSSnake

Standing waves don't have to be from the fundamental tone... (HD and mechanical noises can exit through the port and become noticable)


----------



## chad

MIAaron said:


> Chad, you only need a 1/4 wave for it to propagate. That's why most cars have a bump in the 40-50hz range...the distance from sub to the dash is usually in the 5-7ft area.
> 
> I agree with you on the standing waves in a sub box though.


1/4 wave to propagate but it still won't be standing, but I see what you are saying. Another reason for a bump is as I said earlier while backing my stance on vented enclosures. There will be a hump there because of the interaction between the sub system and the car's acoustics. 1/4 wave or not. It's where the sub system is playing out flat and the car's transfer function is really in full swing. Makes a nice hump there. This is why 'Dang and others prefer a highish F3 to overcome this.



SSSnake said:


> Standing waves don't have to be from the fundamental tone... (HD and mechanical noises can exit through the port and become noticable)


The first harmonic at 100 cycles would be at 5.5 Ft, still rather large. True on the mechanical noise standpoint and batting will certainly help that. 

Chad


----------



## tyroneshoes

So whats youre really saying here is, "My Dad can beat up your Dad"?

No serious, while were in a ported discussion. Lets say you had 1 cubic foot and a port of immeasurble length. The gods provided you with 360 watts and do not frown on either 10s or 12s. What sub would you choose to please the gods who are most interested in the highest outut without loosing sq?


----------



## 60ndown

tyroneshoes said:


> So whats youre really saying here is, "My Dad can beat up your Dad"?


lmao good one  


heres an idea,

how bout we organise a weekend event, as many of us that want can get togehter in an 'out of the way' motel where we can make some noise and a mess.

bring testing equipment and tools amps drivers and our cars.

we can answer all the unanswerd car audio questions DEFINITIVELY and have some fun.

the we post our findings somewhere and make them available for a small 'paypal' fee.

every car audio enthusiast and professional (IN THE WORLD) will pay the $5 to look at our findings 


so thats $5 x 350,000 (views) =$1750000.00000  

which the group that attended the 

'motel definitive testing session' 

get to split  


(even tho im not the brightest have the best ears or any kind of understanding about car audio beyond the ability to blow the odd fuse, i want my cut $$$$ as it was my bloody idea  )


----------



## chad

tyroneshoes said:


> No serious, while were in a ported discussion. Lets say you had 1 cubic foot and a port of immeasurble length. The gods provided you with 360 watts and do not frown on either 10s or 12s. What sub would you choose to please the gods who are most interested in the highest outut without loosing sq?


It's a question you really can't answer, it's not the size of the ship it's the motion of the ocean.

I modeled the 12" and 10" dayton for my app recently after realizing I could have some more room to play with.. The 10" modeled better IMHO. AND was more sensitive.

It is totally possible for a 10" driver to move more air than a 12" driver.

It's very possible for the 10" driver to have radically different specs even in the same line of drivers.

It's just something you have to play with I guess?


----------



## SSSnake

Yes I agree, but if there is any significant energy at the higher harmonics then a standing wave can get pretty ugly (probably a very minor concern, but we are talking about an SQ app... How many times have you spent days looking for interior panel resonances  ).


----------



## chad

SSSnake said:


> How many times have you spent days looking for interior panel resonances



Ugh... Doing that now  But an oscillator really helps get them going nice and hard


----------



## 60ndown

40 second video break anyone.?

http://video.tinypic.com/player.php?v=2lj23kk


----------



## audionutz

SSSnake said:


> Standing waves don't have to be from the fundamental tone... (HD and mechanical noises can exit through the port and become noticable)


Correct! However, it is common practice to address standing waves in enclosures with parallel sides (see also, right angles) for this very reason...standing waves do not need to be X distance long, nor complete waves, to excite enclosure resonances.
A trapezoidal, or non-right angle box is always prefered to the traditional "cube" for this reason.

Marv, looking forward to your call.

AVI, how long until you're finished building?


----------



## MIAaron

chad said:


> 1/4 wave to propagate but it still won't be standing, but I see what you are saying. Another reason for a bump is as I said earlier while backing my stance on vented enclosures. There will be a hump there because of the interaction between the sub system and the car's acoustics. 1/4 wave or not. It's where the sub system is playing out flat and the car's transfer function is really in full swing. Makes a nice hump there. This is why 'Dang and others prefer a highish F3 to overcome this.
> Chad


Ya don't have to tell me, I usa a subsonic filter on my sub for that very reason.  Usually I try to design it that way from the start, but sometimes its just easier to filter it out.


----------



## JAG

OK .... Well , first thing is , my installer made the enclosure 2.25 ft ... So now if I add a square MDF port , the volume will be off. I guess I'll have to stick with the PVC. 
It's been a LOOOOONG time since I have built a ported box with PVC , so I need brushing up on using 90 degree elbows. I need a port length of 13.31" while using 4" pipe .... I'm going to HAVE to incorporate a 90 into the equation , because the box is not deep enough to allow the 13.31" port length from front to back ...... So , please remind me how long a 4" PVC short 90 is considered , when subtracting it from the port length ... If my VERY dusty math is correct , it should be 5.5" ...... Anyone ?


----------



## JAG

JBL's website seems to be down , but I'm almost positive I read where JBL said the enclosure size should be 2.25 cu ft , *and all displacement was already figured in to that ..* If that's true , I could go ahead and use the square port. *BTW , Audionutz ... What size was the square port you wanted me to use ?*


----------



## durwood

AVI said:


> OK .... Well , first thing is , my installer made the enclosure 2.25 ft ... So now if I add a square MDF port , the volume will be off. I guess I'll have to stick with the PVC.
> It's been a LOOOOONG time since I have built a ported box with PVC , so I need brushing up on using 90 degree elbows. I need a port length of 13.31" while using 4" pipe .... I'm going to HAVE to incorporate a 90 into the equation , because the box is not deep enough to allow the 13.31" port length from front to back ...... So , please remind me how long a 4" PVC short 90 is considered , when subtracting it from the port length ... If my VERY dusty math is correct , it should be 5.5" ...... Anyone ?


Measure it from the center.


----------



## chad

You know what I do that's stupid and anal retentive to check my bends to make sure it's right? Fill it with water! I have a couple 90's in my contraption. I measured out a straight pipe, then did the folded pipe. On the first shot I was about 1" too long on the folded. They say measure across the middle of the 90 but the final check was with good 'ol H2O.

Chad


----------



## SSSnake

The JBL manual did in fact say "including driver and port displacements". I'm not sure how Steve's mods (square port and bracing effect the enclosure dimensions). Given the JBL enclosure used 4" diameter PVC I would think that a 3x4x13.3 would get you very close.

Given that I am a fan of round ports (long story that I don't want to add to this debate), I would suggest using the PVC with the FG lining, polyfil, and pantyhose. I would also brace the PVC port.


----------



## tyroneshoes

chad said:


> It's a question you really can't answer, it's not the size of the ship it's the motion of the ocean.
> 
> I modeled the 12" and 10" dayton for my app recently after realizing I could have some more room to play with.. The 10" modeled better IMHO. AND was more sensitive.
> 
> It is totally possible for a 10" driver to move more air than a 12" driver.
> 
> It's very possible for the 10" driver to have radically different specs even in the same line of drivers.
> 
> It's just something you have to play with I guess?


Ive been playing for about a week and I dont have the energy any longer. Please just recommend me a sub thats not the daytonho/hf as I have one in my home and Im weirds like that. Or you can go on over to my post for the best ported sub for my application.

Please


----------



## JAG

chad said:


> You know what I do that's stupid and anal retentive to check my bends to make sure it's right? Fill it with water! I have a couple 90's in my contraption. I measured out a straight pipe, then did the folded pipe. On the first shot I was about 1" too long on the folded. They say measure across the middle of the 90 but the final check was with good 'ol H2O.
> 
> Chad


Simply a great idea Chad .... But is it total volume of the port , or the length that matters ? If it is volume alone , I could always use a 6" round port , and shorten it where I did not have to use any 90 degree elbows at all.


----------



## chad

The bigger the diameter the longer the port  So a 6" would be out of the question.

It's internal volume of the port that counts (da chamber uf air), be it internal or external... Mine are external. If its internal you have to subtract or the entire volume of the port including media.


Chad


----------



## audionutz

no no it's total length sir! Adding port AREA will increase TUNNING FREQUENCY if the port LENGTH stays the same. More on that later.

The formula for area of a circular port (circle) is A=Pi times radius squared
so your 4" port area is 3.1416 X 4 which is 12.567 square inches.

To convert to a square port, it's Area = length times width

So A must stay 12.567...solve the rest based on whatever you want to make one of your port sides with...for example, if you want one dimension of the port to be 2", then the other dimension needs to be 6.28"...thus making this a rectangular port.

These dimensions are INTERNAL PORT DIMENSIONS, so if you build the port from MDF< you gotta account for wood thickness.



And to answer your previouis Q, yes you have to ADD driver displacement AND port displacement into your total internal enclosure volume , which needs to be 2.25 cubes NET.
Your driver will displace somewhere around 0.12 cubic feet, and the port , if made from 3/4" MDF, will displace about 167 cubic inches (or .096 cubic feet total)
Thus, you need to build the overall enclosure to total 2.25 plus 0.12(est)plus 
.096, which is 2.466 total internal.

Get it? got it? good!


----------



## zfactor

okay wow skipped to the end.. i actually usually prefer ported over sealed if built right. water is a great suggestion as is sand or similar. i like reg sand since its not as messy and cleans up easy lol..

very well said nutz..


----------



## JAG

audionutz said:


> no no it's total length sir! Adding port AREA will increase TUNNING FREQUENCY if the port LENGTH stays the same. More on that later.
> 
> The formula for area of a circular port (circle) is A=Pi times radius squared
> so your 4" port area is 3.1416 X 4 which is 12.567 square inches.
> 
> To convert to a square port, it's Area = length times width
> 
> So A must stay 12.567...solve the rest based on whatever you want to make one of your port sides with...for example, if you want one dimension of the port to be 2", then the other dimension needs to be 6.28"...thus making this a rectangular port.
> 
> These dimensions are INTERNAL PORT DIMENSIONS, so if you build the port from MDF< you gotta account for wood thickness.
> 
> 
> 
> And to answer your previouis Q, yes you have to ADD driver displacement AND port displacement into your total internal enclosure volume , which needs to be 2.25 cubes NET.
> Your driver will displace somewhere around 0.12 cubic feet, and the port , if made from 3/4" MDF, will displace about 167 cubic inches (or .096 cubic feet total)
> Thus, you need to build the overall enclosure to total 2.25 plus 0.12(est)plus
> .096, which is 2.466 total internal.
> 
> Get it? got it? good!


Ughh ... No Nutz .... My owner's manual , AS WELL as the JBL website , clearly states the displacements are ALREADY accounted for and included in their 2.25 cu ft box suggestion. So I do not actually need to add anything for displacement.

Secondly , if a port is converted to a rectangular one , like you show above , does the length still remain 13.31 " for that rectangle port ?


----------



## zfactor

ok im looking into this now


----------



## zfactor

if you want 30hz and do 2 x 6.25 slot it would be 13.71 long if i am correct this would equal 12.5" square in of opening just shy of the 4" round

also i did round and get 13.79 long for a tuning of 30hz..


----------



## JAG

zfactor said:


> ok im looking into this now


OK , then seeing how HUGE and bulky a 4" PVC elbow is , it may indeed still be easier for me to build a rectangle slot port then. Also , I can place this rather small sized rectangle port , right out in the middle of the face of the box , eliminating any interaction from the enclosure's side ....


----------



## zfactor

see above we must have posted at the same time

as far as placement.. it most likely will still need a bend same port area = the same length overall.. you could go a bit smaller with the opening and get it shorter but you may end up causing other issues. i generally dont like less than a 4" port with that size enclosure


----------



## JAG

zfactor said:


> if you want 30hz and do 2 x 6.25 slot it would be 13.71 long if i am correct this would equal 12.5" square in of opening just shy of the 4" round
> 
> also i did round and get 13.79 long for a tuning of 30hz..


Well .... According to JBL , the 4" PVC at exactly 13.31" long will give me 30 hz in their reccomended enclosure.

And the 2" x 6.28 " is supposed to be the same area as the 4" PVC .... So how is the length in your calculation different Zfactor ?


----------



## JAG

zfactor said:


> if you want 30hz and do 2 x 6.25 slot it would be 13.71 long if i am correct this would equal 12.5" square in of opening just shy of the 4" round
> 
> also i did round and get 13.79 long for a tuning of 30hz..


Hmmm.... Wonder why JBL says 13.31" long to equal 30 hz then ???


----------



## zfactor

well at 2 x 6.28 slot or 4" round i get 13.79 also. i just made it 6.25 so it was easier. i used termpro and also leap programs to check my tuning btw..some of those cheap online programs i dont trust. i also have bassbox, thunderbox, blaubox among many other i can check in as well but i tend to trust leap and termpro


----------



## JAG

zfactor said:


> see above we must have posted at the same time
> 
> as far as placement.. it most likely will still need a bend same port area = the same length overall.. you could go a bit smaller with the opening and get it shorter but you may end up causing other issues. i generally dont like less than a 4" port with that size enclosure


Oh yeah , I'll still have to bend it .... But a 2" wide slot bend , is much easier to accomplish than a huge 4" PVC elbow ...


----------



## JAG

zfactor said:


> well at 2 x 6.28 slot or 4" round i get 13.79 also. i just made it 6.25 so it was easier. i used termpro and also leap programs to check my tuning btw..


Maybe JBL's numbers are off ....


----------



## zfactor

13.31 and 13.79 is minimal, jbl may have accounted for something additional we did not also.. cant be sure without talking to them to find out


----------



## JAG

Just looked again at JBL's site .... They claim " fo " is 30hz with the 4" x 13.31" PVC port ...... Isn't " *fo* " the tuning freq ??


----------



## JAG

zfactor said:


> 13.31 and 13.79 is minimal, jbl may have accounted for something additional we did not also.. cant be sure without talking to them to find out


Very possible ..... They reccomend fiberglass insulation on ALL interior walls ... I wonder ....


----------



## zfactor

what sub is this i need t/s on it to really be sure of whats going on here


----------



## zfactor

oh yeah btw fo is the same as fs which is the tuning frequency


----------



## JAG

zfactor said:


> what sub is this i need t/s on it to really be sure of whats going on here


Here's the link :

http://www.jbl.com/car/products/product_detail.aspx?prod=W12GTI&ser=GTI&cat=SUB

Click on the SQ enclosure PDF ...


----------



## zfactor

okay the port at 13.31 long will yield a tuning of 30.44728741 lol
at 13.79 it will yield a tuning of 30.00695638 if you want to be specific... just for the record lol


----------



## JAG

zfactor said:


> okay the port at 13.31 long will yield a tuning of 30.44728741 lol
> at 13.79 it will yield a tuning of 30.00695638 if you want to be specific... just for the record lol


LOL ..... All that concern for NOTHING !!! Now I remember , *this* is why I normally use sealed enclosures .... LOL


----------



## zfactor

lol i like to be specific when it comes to ports... thats why i said 13.79 since you said 30 i figured id get you as close as i could


----------



## SSSnake

any news?


----------



## JAG

SSSnake said:


> any news?


Today I finsihed the ported enlosure for the JBL .... I ended up making a rectangular slotted port , and went with Audionutz suggestions for tweaking it even further.

I'm going to give it ALL the benefit of a good listening to , and we'll really put it through the paces .... but I stand prepared to cut that ported box down , and making it sealed if past experience rings true  Testing will probably start tomorrow evening , once all of the sealants have had time to cure completely.
Hopefully , the big Oz sub will be tested within a couple of weeks , but after this JBL has broken in fully first.


----------



## audionutz

Keep us posted, yo.


----------



## JAG

Well well .... See this thread for the continuation :


----------



## mitchyz250f

Bump. What happened?


----------



## mitchyz250f

bump


----------



## Oliver

Mr Marv said:


> *"It needs to be able to play from 80 hz and down , so let's hear it."*
> 
> I think that's the key phrase there^^^^^. I have built literally hundreds of enclosures over the last 7-8 years and I have _never_ heard one that could dig down deep _*and*_ play up to 80 hz as well as a properly built/tuned sealed enclosure.


MrMarv never heard mine [just for the record ]


----------



## ccrobbins

I can't go to the thread listed....So cliff notes needed, what happend?


----------



## jayhawker

There is no myth. The fact is, it is based on listeners preference.


----------



## mvw2

Subwoofer A has a particular sound. It's the same as a particular midwoofer or particular tweeter has a particular sound.

Subwoofer A in a ported box and subwoofer A in a sealed box _will sound the same._ The essence of subwoofer remains the same. Yet, the sensitivity will change (port "EQing" the low end response), there will be some time delay in the lower frequencies (the use of rear waves in the ported enclosure), and because we all change box volume between sealed and ported boxes for the same sub, the final Q changes some too (relative dampening).

I have yet to hear the same sub sound better or worse when using it in a sealed or ported enclosure. The only way a sub has sounded worse is because the box was inappropriate for the sub (really high or low Q, peaky frequency response, etc.) or the frequency response in-car was not good (requiring EQing to flatten out). I have yet to hear a sub sound "different" in either enclosure type other than the obvious frequency response change, any Q change, etc.


----------



## Oliver

sealed and ported 
correctly designed for a MB Q 12"


----------



## SQ4ME2

i prefer sealed myself but one of the best sound boxes i ever heard was a slot ported box my buddy barry did for a Cerwin Vega 18"


----------



## mil81

There is no link as stated above, so I will subcribe and hope AVI gets back on here to report his findings.


----------



## Oliver

Just be patient 

quote> 04-13-2007 <quote

Well well .... See this thread for the continuation :


----------



## 1greek4u

Sealed is a compromise. The trick with any sub system is to tailor is specifically to your own vehicle and install. If you want a ported system (or any subwoofer, for that matter) to play flat in your car you need to take the volume of the interior and the resonant frequency into account.


----------



## chad

1greek4u said:


> Sealed is a compromise. The trick with any sub system is to tailor is specifically to your own vehicle and install. If you want a ported system (or any subwoofer, for that matter) to play flat in your car you need to take the volume of the interior and the resonant frequency into account.


That's beautiful. What's going in it?

But, it can be said, ANY enclosure is a compromise if you look at it from a different angle.


----------



## louisdawon

interesting stuff


----------



## mitchyz250f

Where are the results?


----------



## johnson

http://www.diymobileaudio.com/forum/diy-mobile-audio/11433-jbl-w12gti-first-impressions.html

I'm gonna try the to get a w12gti by the summer and try that enclosure.


----------



## djknowledge

i like both....but i usually go with ported.....


----------



## Crazedkiller

I have only built sealed boxes for the last 25 years for my car audio obsession.


----------



## SQ4ME2

i have built a few ported boxes and 100's of sealed boxes and this is the deal as far as bouilding goes. cars are not all built the same and as thus a ported box is hard to build in a fiberglass enclosure. i like sealed the best and i'm lazy too.


----------



## FG79

I've discussed this issue quite a bit with my friend. He claims you can match the SQ of a sealed enclosure with a vented, but the amount of effort required modeling, testing, tweaking, etc. is usually not justified for car subs. If one of the world's nuttiest, most demanding listeners tells me ported can be done properly, then to me ported has potential. Believe me when I tell you this guy is the Simon Cowell of audio critiquing....he is very critical of the speed of subwoofers in general, so transient response of an enclosure would be a piece of cake to notice by comparison. 

It's easier to just spend more money and buy more subs, and then go sealed. When you're running 4+ subs in a car, you're going to get SPL, low end, etc. etc. I've had nothing but dual 10" sealed setups for a long time now, and I can see how doubling that would suffice most of my needs with no downside. However if I'm limited to 2 subs, I'd probably want to go ported if I could to get more performance out of 2 drivers. 

I like the idea of ported though, it just seems cooler and more adventurous. But often times the enclosure needs to be a bit bigger than you'd like and space is a premium in vehicles. It becomes harder to justify ported for cars except for the coolness factor in most cases....and/or....if $$$ for more drivers is an issue. 

Where I feel ported (and horn loading) are at its best is for midbass drivers. Naturally harder to do in cars, but for home/pro audio it definitely makes sense. Here you can tune down to 45-50 hz (or lower) and enclosure size is usually very reasonable. In most home audio, ported is the norm, sealed the rarity. 

Have heard both sealed/ported in home audio and the only ported ones that sounded boomy were the very cheap, best buy market ones. Anything with true audio enthusiast intent has not sounded sloppy. 

However for home audio subs, I tend to like sealed. An 18" Bag End in 3 cubic foot sealed is a nice all around size.


----------



## FG79

SQ4ME2 said:


> i have built a few ported boxes and 100's of sealed boxes and this is the deal as far as bouilding goes. cars are not all built the same and as thus a ported box is hard to build in a fiberglass enclosure. i like sealed the best and i'm lazy too.


Haha, yeah...forget about fiberglassing anything but a sealed enclosure.


----------



## markland556

This has been a very interesting read.. and still im stuck in the middle... haha


----------



## Fast1one

Remember how enclosures are classified?

Car Audio Subwoofer Enclosures

One thing that is plainly obvious is that higher order enclosures have a steeper roll off, but im sure all of you knew that. Generally, if you go up the ladder you are going to lose some transient response. Second order enclosures have the potential to have better transient response than 4th/6th/8th order enclosures. 

HOWEVER-and this is a big however-This is only ONE variable of the whole equation. Subwoofer specifications, cabin transfer function, and other variables in the system all come into play here. All depends what you are trying to accomplish. 

In my experience, I can get a ported box to be just as "fast" as a sealed enclosure, driver dependent. On that note, I can have a sealed box dig just as low as a ported enclosure, with a linkwitz transform or another form of electronic compensation, again driver dependent. 

I get really tired of people when they say "sealed is way better for SQ". Or "nothing beats the extension/impact of a ported enclosure". These are generally people who do not design, construct, or stuff the "inferior" enclosure properly. 

Want to know what the REAL answer is? Open baffle or Aperiodic (subjective). Hint, only ONE of them is achievable in a car. Oh, and Infinite Baffle is NOT the same as Open baffle 

Cheers!

-Serg


----------



## zGhost

Sealed vs ported. To me this is a simple Q and should be based on the drivers theil small parameters. Run them threw any box design program. And you'll find most drivers are suited for either sealed or ported. Sure you can build either box using the measurements given but over all most subs are in fact designed to be used either sealed or ported from the manufacture (yes there are some that work in either). I also don't understand the theory of ported plays deeper. Its a fact that a woofer in a properly designed box. .6 .7 Q area will play lower than a ported woofer which has the steep roll off right after the tuning frequency to to point of the cone unloading which does not happen in sealed enclosures. As far as the root of the question my uneducated guess is there is no "better sounding" enclosure. Its all based upon what woofer you putting into what enclosure how it sounds. When I hear of a sloppy sounding ported box I immediately think this is a simple case of a improperly tuned box or woofer probably not best suited to this type of enclosure. I myself when buying a sub tend to look for those that perform best in small sealed enclosures. But if the case calls for it I will build a ported. ex the 8" MTX bluethunders I posted in the hot deals section were bought for the fun of it. Upon running the parms they seemed better suited for ported so I build a ported for them. .66 ft^3 port 8" x 2" tuned to 39 hz. f3 37 hz Sound absolutely sweet for 2 1996 era 8's. Also cause i was playing around with them I built a sealed (As Chad stated wood is cheap  ) for them recommended .38 ft^3 f3 60hz. And as I thought the sound was much thinner and weak compared to the ported box. In short I think its all about the woofer not the box. Some are the bomb in ported and some rule in sealed.


----------



## TJ Mobile Audio

@1greek4u, very nicely done. I bet that will sound sweet.



chad said:


> But, it can be said, ANY enclosure is a compromise if you look at it from a different angle.


X2

OK, so here's my take. First off, I know I'm new on the forum, but I've been building systems for several years now.

My take is that ported can sound as good, sometimes better, but it takes careful study of the T/S parameters, long nights trying to remember things from college calculus class, and usually building a prototype or two before getting things perfect.

I have found that fast transients depend on the ported box design as well as the woofer's suspension, I agree that some drivers are simply better suited to sealed boxes. Most can be made to work by making the port smaller or larger than is common, again depending on the suspension of the woofer.

For the flattest bass response, I usually go with a fairly large box tuned at or near the driver's free air resonance, Fs. I have found that this calculator gets me in the right ballpark, if I need to be precise I start tweaking the formulas myself. Subwoofer Box Enclosure Design Calculator - Sealed Ported Bandpass Closed Vented

Right now I'm running an Xtant X1244 (good luck finding one) in a 3.8 CF gross box. The net volume, accounting for driver, port, and braces is 2.8 CF, and tuning is about 27.8 Hz, exactly the driver's Fs. My port is 14" x 2.25" in area, about 32" long (I don't remember the exact length, I built it a couple weeks ago). Anyway, I gained a few dB over my last ported box (2.75 CF gross, 1.75 CF net, tuned to 25 Hz) which itself gained a few dB over 1.2 CF sealed. It also has a 1.5" MDF baffle and plenty of internal bracing, which contributes to clean sound and sheer impact.

On my amp, I have the HPF set at 22 Hz, the LPF set at 72 Hz, both at 24 dB/octave. The woofer starts to unload at 15 to 20 Hz, so the HPF really cleans up the sound protects the speaker as well. With the box described above, I have fast transients, the sound never lags, the bass can be punchy, deep, strong, mellow, smooth, loud, gut-wrenching, teeth-shaking, clean, powerful, tight, etc. all depending on the music I feed it. I've tested it with every genre I could think of, and have not been disappointed. When I demo it, I like to play the game "guess what's in my trunk", and no one has guessed it to be a single 12 in a ported box.

A note on my chosen bandpass of 22 to 72 Hz: the box plays just fine from 20 Hz to at least 120 Hz, but my "door beats" roll off pretty steeply just above 60 Hz, I decided to let them handle from 72 Hz - about 2 KHz (whatever the passive crossover is set at, I haven't tested it) with my tweeters taking it from there. Setting the amp's LPF any higher resulted in an overlap, with an unnatural hump from about 65-72 Hz.

Well, I'm sure some of you won't be convinced, just remember: I didn't say ported _does_ sound as good as sealed, just that it _can_. If that disqualifies me as an audiophile, I guess I'm going down with most Hi-Fi home theater fanatics as well. :laugh: Notice how many high-end home speakers and subs are ported? I know that's a different world, but many of the sonic principles carry over.

Final note, I think sealed sounds much better than ported if the ported box is tuned half an octave or more above Fs. Personal experience, I don't have actual math to back that one up.

Here's a shot from the construction phase:









Here's a shot of the final product:









And here's a link to the whole album:
1989 Nissan Sentra Stereo pictures by tjniels - Photobucket

I know a lot of people have better or worse than I have, I've never poured gobs of money into the hobby, I saw building a good ported box as a good way to increase efficiency without buying another sub. I've got a pretty good ear, maybe I'm dreaming, but I don't think I sacrificed any noticeable SQ. Feel free to check out the whole album, and ask questions, offer advice, compliments, or critiques, just keep this in mind: the components are the best I can afford, and the cheapest I can tolerate. :laugh: I've never been as satisfied with the realism of my bass as I am now, and it's ported.


----------



## koneco

MiniVanMan said:


> A sealed enclosure will generally produce a flatter group delay and phase plot. How that's going to translate to an in-car reproduction is unknown in any given application. When you start reflecting off of surfaces your phasing can get quite a bit out of whack as opposed to the originally produced wave.
> 
> So when somebody says a sealed enclosure seems to blend better with their front stage, their probably not lying. At the lower end of the ported enclosure's response, the phase will be dramatically different than the upper end (i.e. 80 hz). Now granted, the frequencies that this is starting to happen at, and be very noticeable, are frequencies the sealed enclosure is fighting to reproduce, even with EQ. Now this is a generality, and in essence only valid when all other variables are the same. Like I said before, phasing can get screwed up by all sorts of other variables, and not surprisingly, many of them exist in a car.
> 
> So, what does a phase difference equate to. Well, when something is out of phase, that frequency becomes very prominent, or rather stands out. This is pretty common knowledge in the SPL community as it's a trick to get your subwoofer to appear a lot louder. It won't produce higher SPL numbers, but when sitting in the car, it will seem louder. To the SQ person, this can be a problem in that we like our sub's frequency response to blend better with the front stage.
> 
> So, what does a ported enclosure provide? Low end extension, and a generally flatter response down to it's low end. By going with a smaller box, tuned low, you can reduce your group delay, and phasing variations. This could account for the difference in "SQ" that you hear. However, you start to lose the low end extension the ported design affords you. It can still be better than a sealed enclosure, so it's an option in many cases. Extended bass shelfs in a car are pretty useless in my opinion for anything that would resemble an SQ installation.
> 
> All this being said, it comes down to what you want, and what you're willing to sacrifice. Nothing is perfect, and you just do the best you can, with a lot of trial and error. I've found mid sized ported enclosures, tuned low seem to be the best compromise for me. Take me out of the minivan and put me in a Civic, and that may change real quick.


Nothing is perfect, and I think something that is important to all car audio enthusiasts is that NO SETUP IS PERMANENT. Once you buy into all this audio crap, there's always going to be something you can do differently. And then your ears change ...


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## enerlevel

i had brought a prowedge Jl13w7. it was suppose to be sealed. powering it with about 1100rms , the low extension bass was extremely good. it never buckled or souned weird on low bass notes. but on the higher notes , it sounded very dull. 

so then i changed the box to about 35hz @ 4cubic foot. there was alot of change. the output on the higher notes had changed totally. it was like a new sub alltogether. but some low end bass (basstronics- bass i love u) did not sound very solid like. 


therefore i think sealed boxes are much better when it comes to low bass. however tuning a ported box to 28-30hz would yeild the same results but in both cases , the higher notes are very dissapointing. 

for a daily driver , i would alwaz say ported at 35hz.


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## internationlriders

I hope this is relevant but in my experience which isn't super extensive, although I have been in the stereo scene for about 11 years, paper cone subs produce some of the best sounds from a vented enclosure with excellent response. I prefer a slightly small enclosure tuned to mid 30's, line the walls with a bit of poly, and you are almost guaranteed to be impressed. Unless you have a very fine tuned ear for port noise which should be next to nil.  Also many of the best and finest home audio systems have ported enclosures and sound flawless! Am I right?


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## jimmy2345

Normally, someone who want's sq from a ported enclosure is only going ported to boost the lower frequencies that wouldn't be there going sealed. 

Let's say you have a sub that is starting to roll off around 32hz, but you want to take advantage of the 20's as well. You tune the port to 24-26hz and you gain a more flat response and output down into the lower 20's.

This is the only reason I ever run ported as I am not into porting for SPL.


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## kyheng

I love paper cone drivers..... They are able to give the most natural sound compare to other material used.


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## jimmy2345

kyheng said:


> I love paper cone drivers..... They are able to give the most natural sound compare to other material used.


Agree 100%. Effortless natural sound if the rest of the driver is properly designed.


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## DS-21

kyheng said:


> I love paper cone drivers..... They are able to give the most natural sound compare to other material used.


Driver material is one of those things that's so full of myth.

One of the best speakers I've ever heard (Tannoy System 12 DMT II) uses a _poly_ *twelve-inch* cone up to about 1.3kHz. Mine mate seamlessly with aluminum-cone subs (Aurasound drivers) with the subs and the mains both reproducing everything from 150 Hz down.

And in subwoofers, IMO, it's less than unimportant. I've heard great subs with poly cones, paper cones, aluminum dish cones, aluminum cones with mildly pointy dustcaps, titanium cones, composite sandwich cones, synthetic granite cones (old DEI Competition series), etc. IMO, for a sub as long as the cone stays reasonably rigid the motor and suspension are far more important.


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## jimmy2345

DS-21 said:


> Driver material is one of those things that's so full of myth.
> 
> One of the best speakers I've ever heard (Tannoy System 12 DMT II) uses a _poly_ *twelve-inch* cone up to about 1.3kHz. Mine mate seamlessly with aluminum-cone subs (Aurasound drivers) with the subs and the mains both reproducing everything from 150 Hz down.
> 
> And in subwoofers, IMO, it's less than unimportant. I've heard great subs with poly cones, paper cones, aluminum dish cones, aluminum cones with mildly pointy dustcaps, titanium cones, composite sandwich cones, synthetic granite cones (old DEI Competition series), etc. IMO, for a sub as long as the cone stays reasonably rigid the motor and suspension are far more important.


A subwoofer is a speaker too....one that is just as important as any other part of your system. It shouldn't be less sonic or less anything else for that matter just because it's in the back facing your trunk.

I am a fan of paper cone speakers....I believe they just have more detail and sonic fidelity if the rest of the speaker is also built properly. Granted, other types of cones can sound very good as well.

Just like anything else...we all like what we like.


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## mellephants

Hey guys... do you think you can help me decide what to do, or do I really have to build a test enclosure (like Chad's) to figure this out?

The rear hatch area is dead, but the IDQ is (tragically) in a 1.25 cuft prefab enclosure right now. I am asking for advice on making a false floor + amp rack + subwoofer enclosure. I intend to use 2x4's, MDF, and fiberglass. I am not new to audio installations nor subwoofer enclosure design, but this will be my first try with both false floors and fiberglass.

I punched the IDQ12D4V3's parameters into WinISD, and here is the SPL vs Freq for a few different enclosure configurations (see the right of the image for enclosure specs). It sure seems like that 3.3cuft vented box would have the best SQ... but it would be so much easier to just do the manufacturer's recommended 0.88cuft sealed enclosure!

This thread does a good job debunking the whole "Sealed enclosures are best for SQ" myth. It seems like y'all have agreed that this idea is because people make ****ty vented enclosures that aren't tuned correctly. Did I miss something? Are size, laziness, and lack of know-how the only reasons for going sealed, or is there some other advantage?


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## benny z

i would say the manufacturer knows best.


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## ChrisB

mellephants said:


> This thread does a good job debunking the whole "Sealed enclosures are best for SQ" myth. It seems like y'all have agreed that this idea is because people make ****ty vented enclosures that aren't tuned correctly. Did I miss something? Are size, laziness, and lack of know-how the only reasons for going sealed, or is there some other advantage?



It's not quite as easy as one enclosure versus the other when it comes to whether one should run sealed or ported. One needs to factor in their vehicle, the driver chosen, and how they wish to implement it.

First off, let's take the vehicle into consideration. A subwoofer/enclosure combination that works well in a 90s Civic Hatchback will generally not work out so well in a Surburban. Why? The Civic has a huge transfer function, known as cabin gain, whereas the Suburban is so big and spacious, the bass will disappear in that large cabin.

The next thing one needs to do is model their driver in the manufacturer's recommended air space. In some cases, one will find that the manufacturer recommends a sealed enclosure that will have a spike in the 50 Hz range, and drop like a rock on either side of this peak. In a car with a transfer function that peaks in the 50 to 60 Hz range, this sub may seem loud and boomy, yet may not produce any sub bass.

Of course, when it comes to drivers, some drivers just do better in ported enclosures than sealed enclosures whereas others do well in sealed enclosures and can end up destroyed rather quickly in a ported enclosure. One shouldn't try to force a square peg into a round hole!

I could go on and on, but I think you should get the picture that it is not always cut and dry. Subwoofer design and application is usually both subwoofer AND vehicle specific. Until certain variables are known, it usually takes a lot of trial and error to get things right. Prior to getting into modeling software, I used to think that a certain brand of high-end subwoofer wasn't worth the price; until I realized that the manufacturer's enclosure recommendations were not right for my vehicle and its particular cabin gain structure.


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## Oliver

> Are size, laziness, and lack of know-how the only reasons for going sealed, or is there some other advantage?


sealed speakers in small boxes may not be destroyed as quickly as the same sub in a ported box.


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## mellephants

Oliver said:


> sealed speakers in small boxes may not be destroyed as quickly as the same sub in a ported box.


I always highpass my vented drivers right below their tuned frequency...


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## Oliver

That's the way to go


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## mellephants

So far we've just got Benny saying "go sealed because manufacturer says so", which is strikingly un-DIYMA , and Oliver saying "you can hurt your driver if you set up the vented enclosure incorrectly"

I am dissapoint; I want someone to tell me to go with the 3cuft vented, and that the extra space and effort will be worth it!


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## benny z

all that a 3 ft3 enclosure will gain you is enormous amounts of excess weight, space loss, and props from the high school crowd.


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## mellephants

ChrisB said:


> It's not quite as easy as one enclosure versus the other when it comes to whether one should run sealed or ported. One needs to factor in their vehicle, the driver chosen, and how they wish to implement it.
> 
> First off, let's take the vehicle into consideration. A subwoofer/enclosure combination that works well in a 90s Civic Hatchback will generally not work out so well in a Surburban. Why? The Civic has a huge transfer function, known as cabin gain, whereas the Suburban is so big and spacious, the bass will disappear in that large cabin.
> 
> The next thing one needs to do is model their driver in the manufacturer's recommended air space. In some cases, one will find that the manufacturer recommends a sealed enclosure that will have a spike in the 50 Hz range, and drop like a rock on either side of this peak. In a car with a transfer function that peaks in the 50 to 60 Hz range, this sub may seem loud and boomy, yet may not produce any sub bass.
> 
> Of course, when it comes to drivers, some drivers just do better in ported enclosures than sealed enclosures whereas others do well in sealed enclosures and can end up destroyed rather quickly in a ported enclosure. One shouldn't try to force a square peg into a round hole!
> 
> I could go on and on, but I think you should get the picture that it is not always cut and dry. Subwoofer design and application is usually both subwoofer AND vehicle specific. Until certain variables are known, it usually takes a lot of trial and error to get things right. Prior to getting into modeling software, I used to think that a certain brand of high-end subwoofer wasn't worth the price; until I realized that the manufacturer's enclosure recommendations were not right for my vehicle and its particular cabin gain structure.


Somehow I missed this. I think I'm going blind or crazy.

Anyway, good points. To fill in some more information, the vehicle is a Focus hatchback... lots of cabin gain. I guess I have to settle for the fact that there is no way around trial and error. I will have to build a test box or three to find out what is best.


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## cubdenno

Mellephants, What are you trying to achieve?

And why a 3 cu/ft enclosure for a single sub? Is it a 15?

What music do you listen to predominantly? 
How much power on tap?

This is for a subwoofer. If i have learned anything from this forum, its people spend way to much time on worrying about subs in their car.

BTW, I work in Champaign! hello Neighbor!

Woohoo lunch time!!!


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## mellephants

benny z said:


> all that a 3 ft3 enclosure will gain you is enormous amounts of excess weight, space loss, and props from the high school crowd.


ummm


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## benny z

so doit already!


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## mellephants

cubdenno said:


> Mellephants, What are you trying to achieve?
> 
> And why a 3 cu/ft enclosure for a single sub? Is it a 15?
> 
> What music do you listen to predominantly?
> How much power on tap?
> 
> This is for a subwoofer. If i have learned anything from this forum, its people spend way to much time on worrying about subs in their car.
> 
> BTW, I work in Champaign! hello Neighbor!
> 
> Woohoo lunch time!!!


hell yeah local!

3cuft... well, when vented and tuned to 25hz, just LOOK at that response curve!

Power... I am using a JBL BP1200.1, so, more power than the single IDQD4V12 will ever need.

Music... I'm all over the board. Stuff I have listened to lately:

Band of Horses
My Morning Jacket
Pedro the Lion
Bear vs Shark
Flaming Lips
Rage Against the Machine
Brand New
Alexisonfire
White Stripes
Belle and Sebastian
Cracker
Wilco
Daft Punk
Gorillaz
Snoop Dogg
Eminem
Jurassic 5
The Roots
Lupe Fiasco
RJD2
Fugees
Outkast
Tallest man on Earth
Mumford and Sons
Animal Collective
Radiohead
Hot Chip
Daft Punk
Okkervil River
Damien Rice
Bright Eyes
Cursive
Coheed and Cambria
Modest Mouse
Ben Kweller


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## benny z

no michael jackson?


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## Oliver

Looks good for the musical genre you like >>>


> 3cuft... well, when vented and tuned to 25hz, just LOOK at that response curve!


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## mellephants

benny z said:


> no michael jackson?


Hmm WEIRD I actually don't have any Michael Jackson... yet... [scuttles off to favorite torrent tracker]


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## benny z

you're playing... .mp3s (!!!) ...and you're worried about...sub performance???


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## mellephants

Yeah. And IMHO the exhaust and tires on my car are too loud to hear the difference from 320 kbit/s to FLAC.


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## cubdenno

Just remember that increasing box volume decreases power handling.


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## chad

benny z said:


> you're playing... .mp3s (!!!) ...and you're worried about...sub performance???


What are you trying to say?


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## benny z

i try to say lots of things, chad. 

none of them come out right. 

we need to have a central illinois gtg. for srs!


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## cubdenno

I am down with that. I always am looking for a reason to have a beer. oh look!! The sun is shining!! let's have a beer!


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## ChrisB

mellephants said:


> ummm


Once you put that sub in your vehicle, the beautiful flat modeling won't mean much. In other words, you could end up with a ton of low end bloat that will require some cutting via equalization.


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## Oliver

you never look better than on a resume.

paper graphs are ideal


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## mellephants

ChrisB said:


> Once you put that sub in your vehicle, the beautiful flat modeling won't mean much. In other words, you could end up with a ton of low end bloat that will require some cutting via equalization.


Sure, but it still seems logical to aim for the best efficiency in the bandpass that I will be asking the driver to reproduce (25-75hz ish), right?


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## mellephants

benny z said:


> i try to say lots of things, chad.
> 
> none of them come out right.
> 
> we need to have a central illinois gtg. for srs!





cubdenno said:


> I am down with that. I always am looking for a reason to have a beer. oh look!! The sun is shining!! let's have a beer!


yes, YES!


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## ChrisB

mellephants said:


> Sure, but it still seems logical to aim for the best efficiency in the bandpass that I will be asking the driver to reproduce (25-75hz ish), right?


What looks/sounds good in theory doesn't always work out in a real world application. Refer back to my comment about trial and error.

Heck, my motto with integrating a subwoofer into my Mustang was try, fail, repeat, then cheat by purchasing a Stealthbox!


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## mellephants

Hey don't say that, that is basically what I have now! I want a project!! FFFFF


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## mellephants

On the trial and error topic, I already have (or will soon have) the following enclosures to try out

1 cuft sealed (thanks Benny)
1.25 cuft sealed (current)
2.4 cuft sealed (HT box for an Adire Shiva)

I guess I should figure out how big of an enclosure would be easy to build in a false floor/spare well enclosure, then build the equivalent as a rectangular vented enclosure, then try it with various port volumes (trying tuned freqs from about 20hz to 30hz), then decide which to build as a more permanent enclosure.

Yay for winter projects!


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## benny z

...or you could just stick it in the sealed box and call it a day.


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## chad

cubdenno said:


> I am down with that. I always am looking for a reason to have a beer. oh look!! The sun is shining!! let's have a beer!


For some DUMB DUMB reason I did too much of that last night. On the bright side I already found the hangover in that bottle so I should be set for the weekend.



ChrisB said:


> Once you put that sub in your vehicle, the beautiful flat modeling won't mean much. In other words, you could end up with a ton of low end bloat that will require some cutting via equalization.


EQ it out, less power used... That's a good thing IMHO. Why toss a ton of power at a driver in a shoebox when you can toss a little power at the same thing in a vented enclosure, providing you have the space?



benny z said:


> ...or you could just stick it in the sealed box and call it a day.


There's no fun in that :laugh:


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## mellephants

Yeah that is soooo borrrringgg. But I admit I will be a wee bit embarrassed if I wind up using a small sealed enclosure after trying out a vented one


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## mellephants

Also I have a fresh newborn baby and a laundry list of **** I need to get done whenever I can find time, so I won't be able to meet up (or physically fool around with my audio system) for a few weeks.


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## benny z

what about just cutting out the spare tire well and installing a big ole IB sub?

how about you experiment with that while you're at it?



ok, ok, ok...i'll stop being a *******. for now.


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## chad

benny z said:


> what about just cutting out the spare tire well and installing a big ole IB sub?


If I wasn't such a chickenshit I'd do that.. other than the fact that it would be loud as hell outside the car.


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## cubdenno

I think he should just build a wall. Strap the baby stuff up on top and let those smooth vibrations of 15 hertz lull that baby to sleep.


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## chad

to get my kid to go to sleep we used to drive him around and listen to loud metal. I **** you not. Worked 98% of the time, every time.


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## cubdenno

Not surprised. Loud metal... whats not to love?


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## mellephants

benny z said:


> what about just cutting out the spare tire well and installing a big ole IB sub?



LOL ok, for my indoor-only vehicle


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## mellephants

chad said:


> to get my kid to go to sleep we used to drive him around and listen to loud metal. I **** you not. Worked 98% of the time, every time.


loud metal sounds just like being in mommy's belly, right?


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## sqnut

mellephants said:


> Yeah that is soooo borrrringgg. But I admit I will be a wee bit embarrassed if I wind up using a small sealed enclosure after trying out a vented one


If you're going from a ported to sealed, give your ears a week or so to settle in to the new sound. Your first reaction may be a feeling that there is less bass and the typical peak of the ported box is missing. You may also need to fiddle a bit with the mid bass and 2-4khz range to get the right balance between your sub and mid bass. 

Having run both, I prefer the sealed shoe box with a touch fewer watts. 

Good luck.


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## chad

why in the hell do people still think that ported boxes are peaky.... that is boxes you don't buy at best buy.


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## sqnut

chad said:


> why in the hell do people still think that ported boxes are peaky.... that is boxes you don't buy at best buy.


cause most people are plug and play and would either buy from best buy and like or would diy a basic box from a random site. In both cases the chances of the box being peaky would be relatively high. Just following logic. Could be wrong though.


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## ChrisB

chad said:


> EQ it out, less power used... That's a good thing IMHO. Why toss a ton of power at a driver in a shoebox when you can toss a little power at the same thing in a vented enclosure, providing you have the space?


I believe someone already said something about EQing it out!



ChrisB said:


> Once you put that sub in your vehicle, the beautiful flat modeling won't mean much. In other words, you could end up with a ton of low end bloat that will require some *cutting via equalization.*


All kidding aside, I'd rather have to EQ out something that is there versus trying to add a ton of equalization to boost something that is not. I am still amazed at those installers who think a bass boost knob is an adequate substitute for an improper pre-fab subwoofer implementation.


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## benny z

with you there...


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## mellephants

The reason I am at to DIYMA is for the "mature" audience... so please stop assuming I am going to use a prefab or incorrectly designed vented box. If I go vented it will be proper. Sheesh.


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## mellephants

If we can assume all enclosures are designed correctly, is this a good thread summary?

Pros for vented:
efficiency
extension
more fun to design

Pros for sealed:
smaller
easier to design


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## BigGeorge

Back from the dead. Fi SP4 18: Sealed or Ported?


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## SaturnSL1

From what I've read you can get decent SQ from a ported box by tuning really low. Like into the mid 20s. If the information is correct you lose out on overall SPL, but your actual volume should be pretty flat from your tuning frequency on up.


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## chad

Actually overall you gain SPL, but you lose the wicked prefab hump.


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