# 12" or 15" for SQ setup? Big differences?



## ta_nhra02 (Jul 20, 2009)

Hi Everyone!!! I had no help on my last post here so I will try and make this one a little easier. I need a "good" under 300 dollar preferably, 15 inch sub-woofer. I have 4 cubic feet to work with. What are the SQ guys running? I listen to mostly 70's 80's 90's to current rock-hard rock. With a small mix of country and very little rap. I am working with 1000RMS watts at 4ohms. I'm not worried about output. 1K watts already solves that problem. I am looking for a nice musical sub that will handle the power. Box WILL be ported! I am a craftsman. I need to make a decision soon because I want to start cutting wood!
I have not been into car audio for years. I have no local stores around and I am not going into the hood to ask "whats in the trunk".
THANKS!!!!!
Derek.


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## TREETOP (Feb 11, 2009)

I'd recommend looking into the Fi Q15.


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## The Drake (Apr 3, 2007)

ported and quality dont usually go together.... if your looking for higher quality go with a sealed or IB setup. There are a countless number of subs around that are in your price range. Do some research and check around the review section.


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## mikey7182 (Jan 16, 2008)

I'd look into the JBL W15GTi MKII. It will put you at 3 ohms, but your amp may not be that picky.


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## ta_nhra02 (Jul 20, 2009)

"Ported and quality don't usually go together"... Do you mean sound quality? And why do they not go together? I don't get that at all.


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## fastlane (Apr 6, 2009)

ta_nhra02 said:


> "Ported and quality don't usually go together"... Do you mean sound quality? And why do they not go together? I don't get that at all.


No he meant the former. Most guys automatically dismiss ported boxes as being capable of good sq. The problem is, it's really easy to screw up a ported box, whereas sealed boxes are pretty much fool proof. I feel a good ported can sound every bit as good as sealed, but it takes someone who know what they're doing.


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## Tonyguy (Nov 15, 2007)

I got a Focal 15" 38VX that would work awesome for you. Its got 97db efficiency. PM me if interested.


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## The Drake (Apr 3, 2007)

fastlane said:


> No he meant the former. Most guys automatically dismiss ported boxes as being capable of good sq. The problem is, it's really easy to screw up a ported box, whereas sealed boxes are pretty much fool proof. I feel a good ported can sound every bit as good as sealed, but it takes someone who know what they're doing.


I can only speak from experience, but I have had two professionally built custom ported boxes for a single dayton titanic MKIII and an IDMAX, the output was surely there, but wow did they both suffer in sound quality after comparing them in sealed boxes and IB installations.


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## 89grand (Nov 23, 2006)

The Drake said:


> ported and quality dont usually go together.... if your looking for higher quality go with a sealed or IB setup.


I would definitely say that this is incorrect.

There's absolutely nothing wrong with the sound quality of a properly designed and built ported enclosure. In fact, they have a number of advantages.

Yours was probably designed wrong and/or tuned too high.


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## Ziggy (Nov 29, 2007)

Been looking at this today, was trying to find you the Diyma thread link -but I couldn't find it for some strange reason... step up to some 18's!... 
At that price, you could at least try it. 

http://www.pierceaudioproducts.com/

THEN there's this from DIYMA member!: http://www.diymobileaudio.com/forum/classifieds/60817-image-dynamics-idw15s.html


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## WLDock (Sep 27, 2005)

mikey7182 said:


> I'd look into the JBL W15GTi MKII. It will put you at 3 ohms, but your amp may not be that picky.


 There are so many 15's around but I like the W15GTi as well. Will work in 4 cubes ported.
http://manuals.harman.com/JBL/CAR/Technical Sheet/W15GTifn.pdf
Just under $330 shipped on ebay. Will your amp be OK with a 3 Ohm load? Which amp do you have?

While I have used the W12GTi sealed and I had a bud that ran 3 W12GTi ported (Now He is running an 18" SoundSplinter RL-p18 sealed powered by a JBL/CROWN BPX2200.1!!!) the sub is Nice. The three 12's ported off the JBL/CROWN 2200 was crazy lound....but my bud likes the 18" better.

I have only heard the W15GTi mounted Infinite Baffle in a couple of sound quality installs that had 8" midbasses and both had at least 1000 watts to the sub.

















This install is all about sound first and show yet has a ton of power, about 5000 watts. One JBL/CROWN BPX2200.1 per W15GTi. Also has FOCAL Be tweets, 3" mids and SEAS NEXTEL 8" midbasses powered by JBL.









The sub goes low and had a nice dry low overhang type of sound. In both installs a low crossover point was used.


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## Vega-LE (Feb 22, 2009)

I'd go with two twelves (ported) over a single 15. Both boxes would be similar in size. So instead of getting a single 15" 1,000 watt sub, just get two 500 watt 12's.


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## emperorjj1 (Sep 10, 2008)

dont know why we are fighting over it because it doesnt matter for the op. he said will be ported so ported it is. Q 15 sounds like a great idea to me

the debate over ported vs sealed isn't necessarily how it sounds. a correctly tuned ported box will sound good on certain music. but its slow and wont keep up where the sealed would


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## Chaos (Oct 27, 2005)

What do you think about a JL 13W6v2 ?


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## UncleMeat (Jul 14, 2009)

The range and extension requirements of your subwoofer can be determined by your front stage. The deeper your front stage goes, the larger sub I would go, personally. SQ-wise, there's no difference; output wise, the larger subwoofer will benefit from larger cone area, obviously (both, ceteris paribus).


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## 60ndown (Feb 8, 2007)

ta_nhra02 said:


> Hi Everyone!!! I had no help on my last post here so I will try and make this one a little easier. I need a "good" under 300 dollar preferably, 15 inch sub-woofer. I have 4 cubic feet to work with. What are the SQ guys running? I listen to mostly 70's 80's 90's to current rock-hard rock. With a small mix of country and very little rap. I am working with 1000RMS watts at 4ohms. I'm not worried about output. 1K watts already solves that problem. I am looking for a nice musical sub that will handle the power. Box WILL be ported! I am a craftsman. I need to make a decision soon because I want to start cutting wood!
> I have not been into car audio for years. I have no local stores around and I am not going into the hood to ask "whats in the trunk".
> THANKS!!!!!
> Derek.


if you use your subwoofer as a subwoofer (below 80 hz) all quality subs, and sizes will sound about the same.

10s, 12s, 15s, sealed and ported, when tuned correctly should sound about the same.

make sure you buy a quality brand (jbl, jl, alpine, etcetc) and your good.

ive heard a well set up $600 subwoofer/amp combination, and a $4000 sub / amp combination many many times.

they sound the same.

a more expensive one may get 12% louder (maybe), and haver slightly lower distortion (no one can hear it) but do you really want to spend the extra $3400 to impress strangers 3 times a year? (pops trunk wohooo 'bass i love you')

a good $250 15" or 12" sub in a good box with 800 wrms will get so loud you wont be able to drive comfortably (almost everything in the car will be vibrating) . you will likely have to turn it down. and it will sound GREAT.

lots of well respected people here run 10 inch subs with 300 watts and they get loud enough.


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## ungo4 (Jun 5, 2009)

emperorjj1 said:


> dont know why we are fighting over it because it doesnt matter for the op. he said will be ported so ported it is. Q 15 sounds like a great idea to me
> 
> the debate over ported vs sealed isn't necessarily how it sounds. a correctly tuned ported box will sound good on certain music. but its slow and wont keep up where the sealed would


This statement isn't correct. A properly designed ported enclosure can and will sound every bit as good as a sealed enclosure. They are not "slow",this is a function of the driver's motor structure. If this was true then a sealed box should be the slow one because the air spring behind the speaker would keep the it from being able to move properly therefore slowing it down.

The main reason most people don't use ported enclosures is because of size. If you properly tune a ported enclosure then it will almost always be larger than a sealed enclosure for the same speaker. There are some inherent advantages to both sealed and ported boxes.

Here is a good read that explains this subject plus alot more much better that I ever could:
Audiopulse Myths About Subwoofers

Tim


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## ta_nhra02 (Jul 20, 2009)

Hey that's a good read there, thanks!


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## norcalsfinest (Aug 30, 2008)

Arc Audio 15


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## WLDock (Sep 27, 2005)

Looking back.....
I have heard some nice sounding ported subs in the home however I have pretty much run sealed most of the time. But years ago around '94-'96 I built a ported system that sounded good. Most of the ported boxes that I heard back then were too loose or too boomy in the car. But I read a test report in a magazine about a 10" ATOMIC HPW series sub that was tested in an enclosure that was designed to have low group delay like a sealed sub but with all the output of a ported. The sub also went low and matched well with the cars transfer function so it did not have that common "boomy" sound of many ported subs. I built the box to his specs and it turned out to be one of the best ported subs I had heard at that time. I liked it as much as my sealed Boston Pro 10".

So, given the huge number of subs available today that are designed for ported, I am sure a nice sounding system can be built if one takes the time in the design and figure in the interaction the car will have on the output.


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## ungo4 (Jun 5, 2009)

ta_nhra02 said:


> Hey that's a good read there, thanks!


Anytime, just here to help and maybe bust a myth or two every now and then.:blush:

Tim


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## emperorjj1 (Sep 10, 2008)

sorry but i disagree man. im justy going off of my own personal experience working at a shop that builds boxes 95% or more are ported next t-line with a few sealed and very few bandpass. 

comparing a to b sealed vs ported same sub setup ported is more sloppy on certain music. Ya you have to sorta look for it but if you know a few songs with "fast" bass ported just doesn't cut it. big box/small box, any shape, slot port/square port/round port, tiny port huge port ect ive seen em all. the tline is alot better, alot better... but sealed is king


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## GlasSman (Nov 14, 2006)

89grand said:


> I would definitely say that this is incorrect.
> 
> There's absolutely nothing wrong with the sound quality of a properly designed and built ported enclosure. In fact, they have a number of advantages.
> 
> Yours was probably designed wrong and/or tuned too high.


Yep.


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## mvw2 (Oct 2, 2005)

ta_nhra02 said:


> Box WILL be ported!


Why?



emperorjj1 said:


> comparing a to b sealed vs ported same sub setup ported is more sloppy on certain music. Ya you have to sorta look for it but if you know a few songs with "fast" bass ported just doesn't cut it. big box/small box, any shape, slot port/square port/round port, tiny port huge port ect ive seen em all. the tline is alot better, alot better... but sealed is king


???

I've run a good portion of my subs both sealed and ported. The box has very little influence on the end sound. The subs sound the same in either enclosure. The only major difference is frequency response. That's it. In most designs, the final Q will be similar, 0.707 sealed, around 0.55-0.6 ported. There will be some added group delay on the lower end of the ported enclosure, simply a byproduct of the port producing the sound and using the inverted rear side wave.

Do you know every configuration of every box you've heard, the sub specs, the box specs, and know if the sub + enclosure were designed appropriate for each other and for the intended application? If not, then it's tough to compare. The same sub in a sealed and ported enclosure of vastly different configurations will sound very different. However, the same sub in similar configurations will sound very much the same. As well, above say 60Hz-70Hz, the box really doesn't do anything, so upper end response is all sub. The lower end response is all box. What is heard is a combination of sub + enclosure + car gain + EQing. You can very easily end up with something that sounds anemic, bloated, flat, or peaky, and basically everything in between. A LOT of the end sound you hear has to do with frequency response. You get it wrong, things sound like crap. You get it right, all is great. As well, you throw the same sub + enclosure in two different cars, you get two different end sounds.


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## ChrisB (Jul 3, 2008)

89grand said:


> I would definitely say that this is incorrect.
> 
> There's absolutely nothing wrong with the sound quality of a properly designed and built ported enclosure. In fact, they have a number of advantages.
> 
> Yours was probably designed wrong and/or tuned too high.


I agree. Most people who say Ported and SQ don't go together generally build the enclosure too small and tune it too high. Sadly, many car audio manufacturers generally recommend enclosure specs that will sound boomy in the vehicle because they like to take advantage of cabin gain. 

About a year ago I started playing with modeling software because I want to build a HT setup with some leftover subwoofers. I was shocked to see that my subwoofers that were supposed to be in 1.25 cubic feet net tuned to 34 Hz in the car will only play "flat" in 9 cubic feet tuned to 23 Hz.


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## Jroo (May 24, 2006)

For me, I would go to Credence and get their version of the old round solobaric. I guess i shouldnt say their version since they made it anyway. You can get a 15" sealed and wont have to go with a box that big. You can do 4 ohm and get away with a 1.5 cube box sealed, but I would go bigger like around 2 cube.


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## ungo4 (Jun 5, 2009)

emperorjj1 said:


> sorry but i disagree man. im justy going off of my own personal experience working at a shop that builds boxes 95% or more are ported next t-line with a few sealed and very few bandpass.
> 
> comparing a to b sealed vs ported same sub setup ported is more sloppy on certain music. Ya you have to sorta look for it but if you know a few songs with "fast" bass ported just doesn't cut it. big box/small box, any shape, slot port/square port/round port, tiny port huge port ect ive seen em all. the tline is alot better, alot better... but sealed is king


I guess there are alot of really high end home audio speaker designers that would disagree with you as they use ported designs. The truth is that if the enclosure and sub are matched an tuned properly then the ported sub can and will sound just as good as a sealed design. I stand by what I said before.

The problem with ported enclosures is that they are very sensitive to any tiny change in box volume, port length, driver displacement, etc. This makes it easy to be off on one thing and change how the box/driver combo sounds.
Building boxes by hand makes it very difficult to get everything exactly right due to small variances in the human process. 

The tuning frequency has more to do with overall sound than anything else though. Tune it wrong and you get the big response bump like SPL guys use. This factor is the main reason ported boxes have gotten a bad rap in car audio for having bad sound quality.

I respectfully agree to disagree.

Tim


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## pardegt (Jul 28, 2009)

Ive been reading good things on Polk Audio's SR series, good sql and db.


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## Fast1one (Apr 6, 2007)

mvw2 said:


> Why?
> 
> 
> 
> ...


This is a very concise response on what is really going on with this debate. In the end, the final response in the environment influences the sound the most, assuming you use a subwoofer which can work in either alignment. These days, most subwoofers are designed with this kind of versatility anyway. I would also like to add that group delay is most prominent around the tuning region. The solution? Tune lower and use EQ to shape the final response (IE remove some low end to remove "bloat"). EQing some low end out has the advantage of increasing power handling and decreasing distortion, sweet!

Can the post above *PLEASE* be sticked? It seems like there is a sealed v. ported debate weekly now.


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