# SubWoofer: 10 or 12 or 15 or 18



## UaVaj (Jan 10, 2010)

Which subwoofer size will offer 100% SQ while offering the most SPL?

Single 10 or Dual 10 or Single 12" or Dual 12" or Single 15" or Dual 15" or Single 18"

Assume all sub will recieve plenty of clean power up to their max rating. Enclosure will be sealed in their optium size. Budget is of no concern. That means it will be top of the line subs of any brand powered by top of the line amp of any brand.

Do not forget. State your reasoning.


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## cubdenno (Nov 10, 2007)

If you are looking for max SQ AND max SPL, Do a properly designed ported or PR enclosure. 

What are your listening tastes?
How much space are you willing to give up?


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## cubdenno (Nov 10, 2007)

Sorry, skimmed and missed the sealed only and your "why" question.

Generally I recommend going with as big a sub as you can fit. They are usually louder with the same power, they usually get lower easier.
SQ-wise having two will allow you to spread the power between them which helps keep power compression down

All which helps keep distortion down (usually)

Look at these

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=293-674

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=293-666


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## UaVaj (Jan 10, 2010)

As for music. I am all over the place. From blues to rock to classic to rap.

As for space. I have plenty. However I do not want to be one of those vehicle with 10 subs. So the less divers the better.


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## Cruzer (Jul 16, 2010)

if i wanted SQ with as much SPL as i could get, like a single sub setup, i would go with any of these(even has a 21" sub)

DIYCable.com : Intro » Home » Exodus Subwoofers

or any of these (not sure if they do an 18, u would have to ask them, cuz they do 10s but dont show it on the site)

AE Speakers Online Store

but thats just me.


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## cubdenno (Nov 10, 2007)

I love 15's. I would run 18's but the box requirements is usually just way to much. That said, if space was no object and I could fit the correct enclosure, I would do one of those I listed. The 5100 is really intriguing. Pretty much Pro-audio efficiency with small box excursion couple to a LMS coil for low distortion. and I think the Neo motor is shexy. (Note: I am a huge fan of TC subs.) Next choice hands down is a JBL WGTi 15" in a ported enclosure with adequate port area. I can point you in several directions why this is a great sub. it does SQ with barely an equal and it get bloody loud at the same time.


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## UaVaj (Jan 10, 2010)

absolutely NO ported box and NO subsonic filter. The lower a sub can hit the better. There is nothing like the feel of 20hz.

I am a big fan of tc sound too. The 5100 is definitely on the short list.


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## cubdenno (Nov 10, 2007)

Not going to argue the merits of ported. There are enough resources that explain the benefits vs sealed on here or the web.

Then one 5100 or two 15" WGTi's.


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## Cruzer (Jul 16, 2010)

against ported because of size or sq?


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## fish (Jun 30, 2007)

Out of your choices the pair of 15's, more cone area & less excursion to reach desired volume level. If space is unlimited, a pair of 18's would be cool too.

What's your plans for midbass?


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## mattyjman (Aug 6, 2009)

UaVaj said:


> absolutely NO ported box and NO subsonic filter. The lower a sub can hit the better. There is nothing like the feel of 20hz.


have you ever seen a response curve for a sealed enclosure. why in the world would you ask for the "lower the better", and then nix the enclosure that will help you do it the easiest? that's some backwards thinking for sure.


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## sqcomp (Sep 21, 2009)

^I would imagine a lot has to do with the proper design of the enclosure.

Take a look at the ML3800, perhaps Fi's offerings as well.

I'm currently enjoying the 3800 right now in a sealed 1.5 cube. It gets as low as I want and is very responsive in it's transients.


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## mikey7182 (Jan 16, 2008)

Fit the largest woofer you can, especially if you want a single sub setup. Gonna third the comments about a vented enclosure, but if you're absolutely locktight on a sealed enclosure, I would look at a Soundsplinter RL-P15. You may not want a SSF, but a sealed enclosure is more than likely going to have a natural rolloff and produce a SSF of sorts all on its own, and will typically be substantial at higher than 20hz.


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## UaVaj (Jan 10, 2010)

mattyjman said:


> have you ever seen a response curve for a sealed enclosure. why in the world would you ask for the "lower the better", and then nix the enclosure that will help you do it the easiest? that's some backwards thinking for sure.


to me - a ported box's tuned frequency response too just to narrow. not to mention - I have yet to see a ported box play deep enough.

reason for wanting the lowest frequency response is for the "feel the music" effect.

many may say it waste of wattage and that is somewhat true. sadly most have never felt such effect and do not know what it is.

so yes - i do want sealed enclosure. I just have to put enough sub and enough power to boost that low frequency so that the overall full range response is equalize.


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## tornaido_3927 (Nov 23, 2009)

You may want to do a little more reasearch on properly designed and built ported enclosures.. They can get a lot lower than sealed boxes! It would be FAR easier to get to 20hz with a ported box!


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## Cruzer (Jul 16, 2010)

If ported doesn't play low enough, ur sealed plays lows worse. So instead of having closer to playing low enough u opt for having the worst possible lows?


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## cubdenno (Nov 10, 2007)

Cruzer said:


> If ported doesn't play low enough ur sealed plays lower worse so instead of ha ing closer to playing low Enugu u opt for havingthe worst possible lows?


huh? retype this one please.


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## divvide (Apr 4, 2009)

You will have to put yourself in the OP's shoes and see where he is coming from. He listens to all types of music and therefore i do think the sealed is his best bet. Get 2 12" JBL WGTI's and put them in the biggest possible recommended sealed enclosures. Case closed.


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## tornaido_3927 (Nov 23, 2009)

There isn't a specific type of enclosure used for types of music, it is possible to get linear and low bass from a ported enclosure.


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## Cruzer (Jul 16, 2010)

I'm a noob and I got tons to learn. But how do people make up stuff like ported won't sound good with certain music? I don't get it


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## UaVaj (Jan 10, 2010)

tornaido_3927 said:


> You may want to do a little more reasearch on properly designed and built ported enclosures.. They can get a lot lower than sealed boxes! It would be FAR easier to get to 20hz with a ported box!


if 20hz was the only goal - you are correct.

however with a ported box tuned to 20hz. then that will be all I get in return. a boost at the port frequency 20hz. as for the rest of the other low frequencies. it will quickly drop off. not what I want.

since I want a flat response from all low end frequencies. a seal box is better suited.

*just need to find the right driver* with the right clean amp to drive it.



looks like I have to go with the largest single driver I can fit.


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## sqshoestring (Jun 19, 2007)

That is not necessarily true, you port low enough and you will get a flatter curve....it depends on the setup. I'd run with a pair of 15s, mostly because they are large and there is a huge selection of 15s and not near as many 18s though they could work of course. Oh, thats right I have a pair of 15s IB in my car. I even used cheap pyles because I don't even need the output they can generate, but they reach about 25Hz so far and fairly flat above that. AE subs would be better, maybe the Fi too. IB can get really low if you can run it in your vehicle, if you can't ported is certainly second best....maybe better but I like my empty trunk way too much and can easily fit pair of 15s. I bet one better ported 15 would do quite a bit.

The JBL GTi is a monster, it might not be the best SQ sub but if you want loud a great SQ sub may not do it for you. A little EQ on the GTi and it will work well, and is so capable it can do near anything for you. Not that there are not other very capable subs, there are.

Far as porting, if I model my trunk with a port it moves 30Hz from flat to much higher so yes it would have a hump in the response....some other subs would not and if I tuned it lower or changed my trunk size I could change that....but, with that port I can get flat to 20Hz if I cut around 30Hz. Who knows if it is even possible to port a trunk lol, but just saying it will kick up the bottom significantly ported vs not. Problem is I hardly have room in the baffle to even experiment with it, and 25Hz is not something I'm complaining about its IMHO very impressive for $94 worth of subs that will blow out a 4x75 on highs down to 25Hz.

A properly ported SQ box might work like the following: the driver rolls off at 30hz sealed so you port for say 20Hz. This fills in the roll off and now it rolls off at 19Hz. You can't always do that because it might want a box the size of a van, and it depends on the sub. If you want 20Hz I would say start with a 15 or more it is much easier. If you want more output get a pair, if you have the room go larger. I'm still hoping someone on here will run one of the Fi 18" IB subs, I think that was the only 18 I saw tuned for IB when I looked.


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## divvide (Apr 4, 2009)

Sqshoestring.....Correct me if im wrong but isnt the infinite baffle kind of like a huge sealed enclosure?


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## mattyjman (Aug 6, 2009)

UaVaj said:


> if 20hz was the only goal - you are correct.
> 
> however with a ported box tuned to 20hz. then that will be all I get in return. a boost at the port frequency 20hz. as for the rest of the other low frequencies. it will quickly drop off. not what I want.
> 
> since I want a flat response from all low end frequencies. a seal box is better suited.


the idiocracy on this forum is absolutely stunning.  here is a small illustration my friend, of a ported vs sealed enclosure response. orange is ported, yellow is sealed. it's time to let loose of all your preconceived notions, learn something, and then apply it. you almost always can get a ported enclosure to play deeper AND more efficient than a sealed alignment. just think about something before you respond next time....


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## divvide (Apr 4, 2009)

mattyjman said:


> the idiocracy on this forum is absolutely stunning.  here is a small illustration my friend, of a ported vs sealed enclosure response. orange is ported, yellow is sealed. it's time to let loose of all your preconceived notions, learn something, and then apply it. you almost always can get a ported enclosure to play deeper AND more efficient than a sealed alignment. just think about something before you respond next time....


That doesn't prove anything. The sealed enclosure might not have been the largest possible for that specific driver.


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## mattyjman (Aug 6, 2009)

divvide said:


> That doesn't prove anything. The sealed enclosure might not have been the largest possible for that specific driver.


sure it does. it proves that there isn't this "narrow" band that ported boxes play, but rather an extended response. you can tune both sealed and ported enclosures, but that's not the point. the point is that some people should be a bit more open minded, wouldn't you say so?


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## Cruzer (Jul 16, 2010)

divvide said:


> That doesn't prove anything. The sealed enclosure might not have been the largest possible for that specific driver.


When u go with a bigger sealed box, at some point it is too big and sure u gain low end, but u will lose your high end. The OP said he wanted a flat response, one which a huge sealed box cannot do unless he wants the sub just to play a very narrow response. which is not the case because he said that ported plays too narrow of a response.


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## Oliver (Jun 25, 2007)

YouTube - 18 INCH FI AUDIO Q IN A VW GTI

*18 inch Fi Q in a sealed box ^ ^ ^*


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## UaVaj (Jan 10, 2010)

mattyjman said:


>


Picture does says a thousand words.

The orange line is exactly what I am looking for. Flat response from 200hz all the way down to 25Hz.

You think that can be tuned lower further and still remain flat. Say flat response from 100hz to 15hz?


Trick question. Obviously that model is base on 1 watt at 1 meter (laboratory application). What happens to that curve when 1000watt is applied (real world application)? Will that curve remain the same?



BTW what speaker program is that?


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## mattyjman (Aug 6, 2009)

UaVaj said:


> Picture does says a thousand words.
> 
> The orange line is exactly what I am looking for. Flat response from 200hz all the way down to 25Hz.
> 
> ...


your goals are a little unrealistic, i'll just say that... to feel the music at 20hz, you'll actually have to have music down in that octave. most music will have 30, but very few down to 20... plus all the extra power and need from your electrical system to reproduce down there is a little taxing. i would think twice about your goals.

with that being said... you can tune down below 20 if you like. there was an idiot on here last year that turned his whole rapist van into a ported box and tuned it to 18hz. so yah, you can do it. why?

the application is winisd, and it is there to give you an idea. i would play around with it a bit, free download, and figure out what works for you. you do have to take into account cabin gain however, as there is no way of inputing that in this program.


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## Oliver (Jun 25, 2007)

EQ may help to flatten it out .




> *a subwoofer for the deep stuff* did not necessarily give the *best performance in the 50-80 Hz area.*


Subwoofer review summary page ... From the AVS forum - Chase Home Theater



> *Listening procedures:
> *
> All listening us done under blind conditions. The panel of listeners include several very experienced audiophiles, some of whom also design and build high end pro audio speakers. The subwoofers were each placed in the identical room position, and eq'ed to have a fairly flat (3 dB window) response curve from 18 Hz and up, when the subwoofer was able to go that "low".
> 
> Measuring procedures: All measurements are taken at 2 meters/GP from the front baffle of a subwoofer. In the case of a ported sub, the microphone is placed so it is 2 meters from the center of the driver(s) and port. The posted measured results are max "clean" 20 Hz output and the average from 20 to 63 Hz. If *it seemed like the amp was the limiting factor in output*, "AL" is added to the 20 Hz SPL.


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## divvide (Apr 4, 2009)

mattyjman said:


> sure it does. it proves that there isn't this "narrow" band that ported boxes play, but rather an extended response. you can tune both sealed and ported enclosures, but that's not the point. the point is that some people should be a bit more open minded, wouldn't you say so?


Point taken. 

Well here is my concern. I noticed that it said "vented" on the pictured and not ported. So is there a difference between a ported and vented enclosure? Im not saying that a sealed setup is better than a vented. Im just asking which one will reproduce instruments with clarity and the way they are supposed to sound. I've always found ported/vented enclosures to be a little bit boomy.


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## mattyjman (Aug 6, 2009)

^^ perhaps you have never heard a properly tuned ported alignment


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## divvide (Apr 4, 2009)

actually i have. My friend has a 15" Fi in a horn design vented box made by pete kilucki or someone like that. Probably the best low end i have ever heard.


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## Cruzer (Jul 16, 2010)

lol these guys dont even know about winisd and are telling us ported sucks, and is ported the same thing as vented.


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## divvide (Apr 4, 2009)

Cruzer said:


> lol these guys dont even know about winisd and are telling us ported sucks, and is ported the same thing as vented.


Derp..


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## cubdenno (Nov 10, 2007)

Cruzer said:


> lol these guys dont even know about winisd and are telling us ported sucks, and is ported the same thing as vented.


Which is why this and other forums are such a valuable resource. Mocking someone because they may have been previously misinformed can be construed as douche-baggery just as much as the trolls who cruise these forums. Now... If one explains and both parties can't come to terms of agreeing to disagree,and then start throwing around insults, then by all means mock away.


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## Oliver (Jun 25, 2007)

vented/ported , slot , folded slot / round , square = all the same . . . a Helmholtz resonator  in honor of the German physicist Hermann von Helmholtz.


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## divvide (Apr 4, 2009)

Oliver said:


> vented/ported , slot , folded slot / round , square = all the same . . . a Helmholtz resonator  in honor of the German physicist Hermann von Helmholtz.


Learned something there.. thanks 
So i want to clear this up here. I properly tuned vented/ported box is superior to a proper sized sealed box. Am i correct?


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## Danometal (Nov 16, 2009)

I like the efficiency of vented enclosures, but I struggle to be able to build a box to have as low of tuning as I like AND proper port area at the same time. So, I generally like going with the biggest sub I can sealed, and let the transfer function flatten it out (close to optimum box size as possible though)

Too high of tuning (35 hz +) is what hoses the SQ of a ported box, IMO. I like 22-28 hz tuning myself, but again, that's hard to do. 28 - 30 is pretty easy though, and that sounds good with most music, just no super sub-sonic bass... 

And, then there's passive radiators. I'm considering a pair myself...

Peace.


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## Cruzer (Jul 16, 2010)

cubdenno said:


> Which is why this and other forums are such a valuable resource. Mocking someone because they may have been previously misinformed can be construed as douche-baggery just as much as the trolls who cruise these forums. Now... If one explains and both parties can't come to terms of agreeing to disagree,and then start throwing around insults, then by all means mock away.


I understand the point of the forums.

when i came here i learned lots, i asked questions left and right.

Why i said what i did, was because i didnt pretend to know everything. i didnt tell people who answered my questions they were wrong.

whoever, 1 or 2 people, continually told us all we were wrong ported wouldnt play low, wouldnt be good for sq, etc etc

if they just asked, and we answered, and they asked for more details or a more thorough explanation, cool, great, perfectly acceptable and expected. but to tell multiple people giving advice they are wrong is just not how u learn


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## UaVaj (Jan 10, 2010)

mattyjman said:


> your goals are a little unrealistic, i'll just say that... to feel the music at 20hz, you'll actually have to have music down in that octave. most music will have 30, but very few down to 20... plus all the extra power and need from your electrical system to reproduce down there is a little taxing. i would think twice about your goals.
> 
> with that being said... you can tune down below 20 if you like. there was an idiot on here last year that turned his whole rapist van into a ported box and tuned it to 18hz. so yah, you can do it. why?
> 
> the application is winisd, and it is there to give you an idea. i would play around with it a bit, free download, and figure out what works for you. you do have to take into account cabin gain however, as there is no way of inputing that in this program.


the goal may NOT be what most "joe" wants. chances are - most joe does not even have a clue as to what is missing off the frequency response curve - what they do not know they do not miss.
however the goal is REAL. with the right driver in the right box and with enough clean power. it can happen.

as for why? while most are happy with an unbalance 50hz to 20kHz response (with even more boost at 80hz).
instead - I simply want a flat 20hz (or as low as it can go) to 20Khz response.

thank for the program referral. hopefully that will give me better predictions/planning.
as for cabin gain. I have a digital parametric eq to help flatten out the response.


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## tornaido_3927 (Nov 23, 2009)

Well for starters you don't NEED you sub to play flat down to 20hz for it to be flat to 20hz in a car, a little friend called cabin gain will help you out a lot here. Do you know what kind/level of cabin gain your vehicle has to boost the low frequencies?


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## Oliver (Jun 25, 2007)




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## subwoofery (Nov 9, 2008)

UaVaj said:


> the goal may NOT be what most "joe" wants. chances are - most joe does not even have a clue as to what is missing off the frequency response curve - what they do not know they do not miss.
> however the goal is REAL. with the right driver in the right box and with enough clean power. it can happen.
> 
> as for why? while most are happy with an unbalance 50hz to 20kHz response (with even more boost at 80hz).
> ...


Problem if you want a flat 20Hz-20kHz freq response is that it won't sound good when driving. You'll have pretty much no low end and all highs with a bitty sound in the midrange. 

Here's what you should aim for: 









Good read: 
http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/11579-flat-response.html 

Kelvin


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## UaVaj (Jan 10, 2010)

Everyone - thanks for all the responses.

If no one object. I gonna go with TC Sound Ultra 5400 18"

Speak now or forever hold your peace.


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## Cruzer (Jul 16, 2010)

where u getting it from?


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## sqshoestring (Jun 19, 2007)

Its hard to get to 20Hz and there are various ways to try. I put a pair of 15 in IB so it is easier for them, I can get 25Hz but not much below that. You can get a honking sub like a JBL GTi and feed it well, then EQ the bottom up, lot of people do that because it takes less room though my trunk is empty. PR is ideal because you get rid of a long port, though not that many people do it. PRs were on sale at a sub place the other day exile or something I forget. IB might not make the SPL some are after and only some vehicles can run it, but it needs less power in general. It is hard to get under 30Hz much no matter what you do, you have your work cut out for you. I don't need to EQ down to 30 like the model of my subs predicts, however I can boost 20 on the EQ. According to the model my car does not have much cabin gain. With various small box (but not expensive) subs I could hardly get to 35Hz it had a serious problem. I could hit 40-50Hz hard but I hate that. The IB will shake the car its great. Still hard to control also as you change sources some have a lot of bottom and others have none.

Seems to me vented can be more than one thing, it can be ported or it could be an aperiodic vent in a sealed box. That is how I try to use the terms anyway though they are pretty much interchangeable and few use AP vents.


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## divvide (Apr 4, 2009)

Not to sidetrack the thread or anything (even though i kind of am)...besides since all the gurus have their attention here, has anyone been able to get a decent flat reponse from a bandpass type enclosure? curious because i plan to do a 10" for a convertible.


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## cubdenno (Nov 10, 2007)

Pete Kulicki designed a single reflex for my TC3000. It is flat in car 30-70 hertz. Efficient and very musical. Handles gobs of power as well. Only issue is it is bigger than me. He seems to be very busy right now, but his designs are worth the money.

pwkdesigns.com

At least give him a look


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## fish (Jun 30, 2007)

cubdenno said:


> Pete Kulicki designed a single reflex for my TC3000. It is flat in car 30-70 hertz. Efficient and very musical. Handles gobs of power as well. Only issue is it is bigger than me. He seems to be very busy right now, but his designs are worth the money.
> 
> 
> pwkdesigns.com
> ...


Word... he can pretty much do whatever you want.


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## divvide (Apr 4, 2009)

correction... My friend had an audio Q 15 in an enclosure deisgned by pete. Worth every penny plus the waiting time.


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## divvide (Apr 4, 2009)

so no one has any input on how 2 12's would sound sq wise in a bandpass enclosure? If ported enclosures have come so far to achieve such results, can't a bandpass enclosure be tuned to the same results?


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## cubdenno (Nov 10, 2007)

short answer: yes


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## tornaido_3927 (Nov 23, 2009)

Slightly less short answer, no. A bandpass has quite a small bandwidth and eliminates some distortion (even order I think..?) and has a steep rolloff on the top and bottom.. Which is obviously dissimilar from a ported enclosure.

You _can_ achieve good results with a properly modelled and built enclosure for a couple twelves, but you won't get the _same_ results as a ported box.


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## cubdenno (Nov 10, 2007)

tornaido_3927 said:


> Slightly less short answer, no. A bandpass has quite a small bandwidth and eliminates some distortion (even order I think..?) and has a steep rolloff on the top and bottom.. Which is obviously dissimilar from a ported enclosure.
> 
> You _can_ achieve good results with a properly modelled and built enclosure for a couple twelves, but you won't get the _same_ results as a ported box.


LOL! Going to have to agree to disagree.

Bandpass enclosures got a bum rap starting in the 90's. Bad designs that were peaky for boom factor ruined a lot of peoples desires for one. Remember that you are mechanically forcing the sub to play a small "band" of frequencies. How one designs the enclosure will dictate that "band". 

here is a quote from another website. I can't remember where though. I just copied and pasted it in a word doc for reference.

# These enclosures seem to be the latest rage in the car audio world. It would probably surprise many people to know that these designs have been around for many years. The first patent for a bandpass enclosure was filed in 1934 by Andre d'Alton. In the last ten years, interest has been renewed in these enclosure designs and substantial strides have been made in defining their behavior. Many home sub/satellite speaker systems currently use bandpass designs for low-frequency reproduction. Designs from Bose, KEF, AR, and many others have become very popular in home audio circles. 
# In a bandpass box design, the woofer no longer plays directly into the listening area. Instead, the entire output of the subwoofer system is produced through the port or ports. In a conventional sealed or ported subwoofer system the low-frequency extension is controlled by the interaction of the speaker and the enclosure design, but the high frequency response is a result of the speaker's natural frequency response capability (unless limited by a crossover.) In a bandpass enclosure, the front of the speaker fires into a chamber which is tuned by a port. This ported front chamber acts as a low-pass filter which acoustically limits the high- frequency response of the subwoofer system. The name "bandpass" is really pretty descriptive in that it refers to the fact that the enclosure will only allow a certain frequency "band" (range) to "pass" into the listening environment. 
# So what? Couldn't the same thing be accomplished by placing a low pass crossover on the subwoofer system? Yes, it could, but a bandpass enclosure can produce significant performance benefits in terms of efficiency and/or deep bass extension that would not be possible in conventional designs of equal size. 
# By adjusting the volumes of the front and rear chambers and the tuning of the port or ports, significant performance trade-offs can be created. When box parameters are adjusted for a narrower bandwidth, the efficiency of the subwoofer system within that bandwidth increases and can reach gains of up to 8dB (sometimes even higher.) As box parameters are adjusted for wider bandwidths, very impressive low-frequency extension can be produced from extremely compact enclosures at the expense of efficiency and good transient response. Intermediate bandwidths can also be designed which create a compromise between all these characteristics. As if that is not confusing enough, within each bandwidth range, the designer can also manipulate box parameters to shift the range of operation up or down the sub-bass range which also has an effect on efficiency. 
# As you can see, bandpass enclosures can have very different sound characteristics based on the designer's choice of box parameters. As such, it is not always possible to make blanket statements as to the performance benefits and drawbacks of bandpass enclosures in general. 
# One characteristic of bandpass enclosures which is universal is that they exert greater control over cone motion over a wider frequency band than conventional designs. Due to controlled, rapidly changing air pressure on either side of the woofer, the woofer is capable of producing high levels of acoustic output without physically moving very much. This means that the woofer is less likely to encounter excursion limits in the main part of the sub-bass range. However, just because the cone isn't moving as much doesn't mean that the speaker's motor assembly isn't still trying to drive the cone hard; it just means that the speaker cone is encountering resistance to motion. This resistance can be very hard on speakers, especially when crazy car audiophiles are at the controls. The conflict between the force generated by the motor assembly and the air pressure in the enclosure can impose extreme stress on the glue joints and suspensions of the woofers. You can literally tear a speaker apart in a bandpass enclosure if you apply too much power. Because the speaker is not moving as much and because noises are masked by the front chamber, it is also very difficult to hear when a woofer is in serious trouble. Many people have been known to crank bandpass enclosures up and blow the speaker to bits within a few minutes because they did not realize that the speaker was having a heart attack. Choosing the right amount of power and carefully setting amplifier gains is very important in order to ensure long- term reliability. 
# Bandpass enclosures can be divided into two basic types: single- reflex and dual-reflex. In a single-reflex design, the rear chamber is sealed and the front chamber is ported. In a dual-reflex design, both front and rear chambers are ported into the listening area. A variation of the dual-reflex and single-reflex, known as "series-tuned," has a port which connects the rear and front chambers. 
# The differences between single-reflex and dual-reflex bandpasses are similar to the differences between sealed and ported enclosures. A single-reflex typically exhibits a shallower low-frequency roll- off rate (approximately12dB/octave) and better transient response. A dual-reflex is more efficient and controls cone-motion over a wider range but typically has a sharper (18-24dB/octave) low- frequency roll-off. Because of the difference in low-frequency roll- off rates, a dual-reflex usually has to be larger in size to produce the same low-frequency extension as a single-reflex design. 
# As compared to more conventional enclosure designs, bandpass enclosures are very complex to design and build. The rules governing the performance of bandpass enclosures leave no room for error. Slight volume miscalculations or sloppy construction can turn a good design into a poor-performing box. Integrating the proper size port or ports can be extremely challenging and often renders designs that looked great on paper completely impractical. The design of these boxes should definitely be left to people with extensive enclosure- building experience.


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## wink1969 (Mar 17, 2010)

If you go to Pete (PWK designs) and fill out the form he has he will get back with you and tell you what will be the best enclosure for your car/truck. He makes his designs for the sub and your car/truck and considers cabin gain. Some times a sealed box will do the trick some times ported or bandpass. That's why he has a form that lets you tell him exactly what you want your subs to do and how much power (which amp or amps) you will be running and what sub and how many. I have gotten alot of designs from Pete from SQ to SPL to just plain loud enclosures for my cars and they all did what I asked and sometimes it is a simple ported box to a complex t-line to folded horn and bandpass but they all where great.


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## cubdenno (Nov 10, 2007)

wink1969 said:


> If you go to Pete (PWK designs) and fill out the form he has he will get back with you and tell you what will be the best enclosure for your car/truck. He makes his designs for the sub and your car/truck and considers cabin gain. Some times a sealed box will do the trick some times ported or bandpass. That's why he has a form that lets you tell him exactly what you want your subs to do and how much power (which amp or amps) you will be running and what sub and how many. I have gotten alot of designs from Pete from SQ to SPL to just plain loud enclosures for my cars and they all did what I asked and sometimes it is a simple ported box to a complex t-line to folded horn and bandpass but they all where great.


LOL!! I have 5 designs myself from 2 for my 15" to a quad 10 and a quad 8 for my son and a single 10 for my brother. Money well spent.


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## UaVaj (Jan 10, 2010)

cubdenno and mattyman
you two brought up a great discussion with evidence regarding how bandpass enclosure and ported enclosure can better fill the low end frequency loss that sealed enclosure is having a hard time reproducing.
point taken.



do note that post #1 did request 100% SQ. Can a ported enclosure reallie out perform a sealed enclosure in regards to SQ?
i would rather have (A) 100% SQ at an average ~6db loss of low end frequency with a sealed enclosure than (B) to recover that ~6db loss for a flat response at the cost of SQ.



unless there is a way to have both - maintain 100% SQ and still recover that ~6db for a flat low end response. I will have to give pkwdesign a shout.


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## sqshoestring (Jun 19, 2007)

Bandpass can work just fine, but you have to often change the system to make it work well. They do tend to have a more narrow response, that means if you want it to play low you need mids/MB to play lower to reach the BP. If you don't care about bottom, then its not as big a deal but can still have a more steep slope on the top side to deal with. Since you can do the same thing with electronics nearly, and a ported box with around the same output is significantly smaller...most people do that instead of a BP. A BP can have a lot of output more than ported, but it will then have an even more narrow passband. More narrow band=more SPL=less SQ. Wide band=less SPL output. So you can use one sure, and make it work well, the question is why bother. That is not to say a BP or transmission line or horn is not cool and all, but they are not common for good reasons.


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## tornaido_3927 (Nov 23, 2009)

cubdenno said:


> LOL! Going to have to agree to disagree.
> 
> Bandpass enclosures got a bum rap starting in the 90's. Bad designs that were peaky for boom factor ruined a lot of peoples desires for one. Remember that you are mechanically forcing the sub to play a small "band" of frequencies. How one designs the enclosure will dictate that "band".
> 
> here is a quote from another website. I can't remember where though. I just copied and pasted it in a word doc for reference.


Which is why I said a properly designed and built enclosure, the opposite of what you are describing 

But yeah, pretty much what sqshoestring said is my view on it, it all depends on your goals and situation really..


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## sqshoestring (Jun 19, 2007)

I built one long ago with a cheap DVC 10, its a big thing I think 1.5cf each side or something. I hooked it to a home stereo, on my PC. Then I could listen to CDs, mp3, radio, all with a subwoofer and these small bookshelf speakers I had...with no crossover needed. Since it was 4 ohm that boosted the sub output some and it worked perfect on a 2x35w receiver. I tried it in a car a couple times and it worked, but it was big. Once I ran it with a cheap bought jensen single 10 BP (just to see), it was funny it worked really well; the deal was the jensen was tuned pretty high and it slotted in above the one I built. It filled the whole trunk nearly but the response was great top to bottom for a sub out of two cheap 10s. It went fairly loud given what they were. I only had 300rms on them or something.

If you want to run a BP go for it, that is what this hobby is all about. Just be prepared to handle the issues with one such as a narrow band, larger size, hard to hear it clip, etc. You must tune it spot on or you will get crap, and you must use the right sub. I later built another BP box for an 8" sub, I wanted a smaller box under my PC desk. Oops, the thing didn't work. Years later I found it stored, I had built them out of a book so I checked both in winISD and the boxes were the right size and ports, but the 8" sub was the wrong one and the curve just sucked like two hills far apart. The 10 the curve was great like a hill with the top cut off flat. The 8" was an IB sub, but I never investigated to see if that was the only reason it didn't work. I mean I could not change the box or port within reason to make it work, there was no way that 8 was going to work.


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## cubdenno (Nov 10, 2007)

UaVaj said:


> cubdenno and mattyman
> you two brought up a great discussion with evidence regarding how bandpass enclosure and ported enclosure can better fill the low end frequency loss that sealed enclosure is having a hard time reproducing.
> point taken.
> 
> ...


Absolutely. sealed enclosures are smaller, easier to build and way more forgiving. 

transfer function/cabin gain is different for every car but again, the roll off of the sealed will usually closely match the rise by cabin gain. It's why a lot of people love sealed and why you can get in car bass from a 5" speaker (cabin gain)

Now you can get great sound from a ported but some designing has to be done. Sure you can throw a cookie cutter ported box in your car but the result might sound like ass. Boomy, muddy whatever. Bad. This is why so many people dislike ported. But get a well designed ported enclosure and you will be happy. it will go audibly lower usually using less power to get there at the same volume as the sealed. Which lowers power compression and distortion as well.

The main 3 reasons why band pass enclosures are not done usually is because they are a PIA to design correctly the bad rep from poor designs and they are feggin big. Most people don't want to take up their trunk/hatch/wherever with 8 total cubes of box+. 

remember also, we are talking about what, 2 octaves? 20-80 hertz. Easy enough to get great response that mimics the "SQ of the sealed enclosure" with the efficiency of a ported or like SQShoe said degrease the band and get even more efficiency. Or get a huge peak that covers a tiny range of frequencies that overwhelms all the others for the spl junkie (note: will sound like refried ass.)

I guess i appear to be argumentative on this. And I apologize. Like anything else, if it's designed and implemented correctly, whatever enclosure you choose will give you great results. Just remember there are trade offs with each design in performance, size and complexity.


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## UaVaj (Jan 10, 2010)

cubdenno said:


> remember also, we are talking about what, 2 octaves? 20-80 hertz. Easy enough to get great response that mimics the "SQ of the sealed enclosure" with the efficiency of a ported.
> 
> I guess i appear to be argumentative on this. And I apologize. Like anything else, if it's designed and implemented correctly, whatever enclosure you choose will give you great results. Just remember there are trade offs with each design in performance, size and complexity.


after playing with WinISD. I can understand the advantage you speak of regarding optimum ported enclosure. the frequency response is definitely better.

the big question is: is the "transient response" of the ported enclosure comparable to a sealed enclosure?

WinISD does not state this info regarding ported enclosure. Is there a reason why WinISD neglect to not include this information for ported enclosure? *Is there a way to figure out the transient response for ported enclosure?*



in regard to enclosure. I will go with whatever size (that can fit in the back seat of a F350 CrewCab) or whatever design (seal, port, bandpass, baffle, whatever). Chances are WindISD or pkwdesign can design the optimun enclosure based on small thiele parameters.

*back to the original question: which driver (brand/model) can deliver a flat and transisent response (qts of 0.7) for 20hz - 80hz?* and *can WinISD verify it?*


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## tornaido_3927 (Nov 23, 2009)

The flattest response is actually with a Qtc of closer to 0.5 but 0.707 is the best tradeoff of transient response, power handling and low end response. The Qtc applies more the sealed enclosure and you won't get a Qtc from a modelling program for a ported enclosure.

Generally the transient response is mimicked in the modelled response of the speaker, so a nice flat Qtc of 0.5 gives you a great transient response, a ported enclosure with a huge bump in the frequency response will yeild a poor transient response. However a ported enclosure with a good, flat response will be what you would aim for in regards to transience.


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