Help with the sub section of a 5.1 system

Car stereo's aren't really my domain of knowledge, home theater is. So I want to get some ideas from people that are more in the know. I have a 2001 Maxima SE that I'm putting in a Pioneer AVH-P7500DVD HU. The reason for this HU is the DVDa 5.1 capabilities as I'm a DVDa authorer. I have nice componet speakers in the front and combos in the back from a previous system with a decent amp (Alpine 4 channel).

The big issue I have is an older, not well thought out, 2x 12" subwoofer setup. It can go. I'll save it for use in a new truck next year. The current box just doesn't sit right in the trunk at only 32" wide. It litterally crushes and sinks into the spare tire wheel well. I was considering a 38"W x 14"D x 12"H generic 3x 12" pre-fab box. That width would litteraly fit snug from wheel well to wheel well. It would also elevate the box in the middle to a couple of inches above the cover for the spare tire. I'm more concerned with hauling grocieries than showing off any speakers.

My problem is I don't have a table saw or decent equipment to build my own custom box. I'm not looking to impress anyone with my bass capabilities as I am an audiophile, not an attention seeker. I'm looking for a recommendation on good subs and amp (preferably one) that would work for this setup. Or, alternative suggestions if my ideas are misguided. My budget is about $1000. Thanks.

since your goal is sound quality and not SPL I would seal a single 15" sub. Try to find a used brahma 15 from adire (they are not in stock at adire and won't be again). Or you could seal and avalanche 15 from ascendant audio www.ascendantaudio.com

since your goal is sound quality and not SPL I would seal a single 15" sub.

My worry about 15" drivers is the flabby bass response. Generally I've found 10" and 12" drivers to respond faster and give a tighter bass definition. I'm a thrash metal / prog metal fan, so I need bass that can respond. Is there something that makes this particular 15" driver respond with the speed and accuracy of a 10" or 12" driver?

Lastly, the position in which I can put the box for the sub has a height limitation of around 18". I don't know what the norm is for a 15" driver.

It may seem that way with usual mainstream crap, but these subs have linear motors (xbl^2) and are geared for ultimate sound quality. I installed an avalanche 18 recently and that and my friends brahma 15 are the two best sound quality substages I've ever heard. I've also head a LOT of 10's and 12's ported and sealed. From the sounds of what your looking for I think a brahma15 or avalanche 15 would be perfect!

My worry about 15" drivers is the flabby bass response. Generally I've found 10" and 12" drivers to respond faster and give a tighter bass definition. I'm a thrash metal / prog metal fan, so I need bass that can respond. Is there something that makes this particular 15" driver respond with the speed and accuracy of a 10" or 12" driver?

Lastly, the position in which I can put the box for the sub has a height limitation of around 18". I don't know what the norm is for a 15" driver.

Ditto the above. You do not want a 15" for 5.1 dvd system. Oh, B-stang, don't even act as if you know what this is all about either. I'll warn others that he'll flame the snot out of you if you suggest anything other than what he suggests. Also dlt90, he can't give an exact answer to why he says this 15" doesn't sound muddy. He just give's his preference.

Since space is a concern I'd look into either 2-10" or one 12" woofer in a sealed enlcosure. The new SX line from DEI is a real treat http://directed.com/audio/subs/default.asp . They're nice and rugged, very responsive and work well in a small sealed enclosure. With over 2" of usable cone travel, they'll pound great and clear for those heavy metal notes. I love how they sound with my old Metallica tunes!

You'll want either the d1200 amp for one sub or d2400 for 2 subs. Both of them are classD mono amps just for subs. Again, these things are pretty hefty items.

No matter what you choose to do, you really need to have a proper custom box made to compliment your vehicle. Many people don't give much thought on the enclosure but that's one of the most important items. You gotta build the right box for the right subs for the right vehicle. If not, it just won't work at the full potential.

DEI SX= not a flat response at all..... needs a HUGE box to get anything sub 40hz decently when sealed. Honestly man check out brahma and avalanche 15's they sound great. Talk to sr20 who's on here he runs a sealed brahma 15 and haas your listening tastes and couldn't be more happy with it. Obviously poncho has no clue what a good 15 is with his description above..... brahmas and avalanches are some of the best sound quality subs period. Also check out Image Dynamics IDmaxes and RE xxx's.

Is there something that makes this particular 15" driver respond with the speed and accuracy of a 10" or 12" driver?


The problem with this question is it starts with the assumption that 10's and 12's are somehow magically "faster" than 15's. Since that's completely untrue it's kind of hard to answer you.

God I don't even know where to begin....I guess I'll just start by asking why you think 10's and 12's are faster? If you feed a sub a solid tone it will play that tone, which means it MUST oscillate a certain number of times per second (also known as the frequency, measured in hertz). If a sub was "slower" it wouldn't oscillate as many times in that one second period and essentially it would be playing a different frequency, which we know is impossible.

Or do you mean it doesn't respond as quickly to transients? If so then why not? Because the cone weighs more? So what? Sure given everything else equal it would accelerate slower, but it will still start at the same point in time, reverse direction at the same point in time, and stop at the same point in time. It just won't move as far as a sub with a lighter cone. But this is holding everything else equal, all the sub manufacturer has to do is tweak the suspension a little to allow the cone to move farther on a given amount of power and that completely takes care of that problem, now the sub with the larger cone will move just as quickly and effortlessly as the sub with the smaller cone, it's just sweeping more air while it does it because of the larger radiating surface.

I don't know how this stupid "large subs are slow" myth got started, my guess is it's a result of the mainstream brands shoving their subs in boxes that were WAY too small so people wouldn't instantly turn them down (small boxes are attractive, whether they improve or destroy the sub's sound is irrelevent). A smaller box will have a higher damping ratio, when the DR gets to be too high (~.8-.9) the sub's transient response suffers, no matter what sub it is. With smaller subs this isn't much of a problem because their optimum box size is small enough where people will still buy it, but the large subs require very large boxes, probably too big for the average person to want, so instead they stick them in small boxes to sell more and don't give two craps how it ends up sounding. So now you have people running around with 10's in perfectly matched boxes, 12's in reasonably matched boxes, and 15's in horribly matched boxes. Out of that comes the rumor that larger subs by nature are slow and sloppy while smaller subs are quick and punchy, when in fact it's the boxes that are bringing about these "conclusions". I'm not sure if this is accurate, it's really more of an educated guess, but one look at the boxes these mainstream companies stick their subs in tends to support it.

Besides, subbass by nature is pretty sloppy. I mean the reason why it's subbass is because the frequency is low, and low frequencies are slow. If they were faster then they would be higher frequencies, but they aren't, they're low. It's really the midbass that gives the subbass any kind of definition. Without midbass, subbass is just a series of rumbles, that goes for ANY speaker playing those frequencies. If you want the quick punch that is present in metal then you need to focus on your midbass, not your sub. Hell on most rock/metal songs you could go completely without a sub if you have strong mids.

sr20de4evr, that seems like a very good and logical conclusion. Personally, I really don't know. What I do know is that no one subwoofer or size is a cure all for everyone. In general, I do not like 15's in a car unless acoustially it sucks so bad it needs a 15 or even a 18. Also, not every 10 or 12 can be put into a small, sealed box and sound great in every car. Like I always say, everything is revalent upon everything. Oh, yes, you can easily have 12 or even 10's go below 20htz but in most cars, that's worthless. At that point that just rattles your nuts and isn't very audible. In the mid 30's on up is what you actually feel hit and can hear.

While not an expert by any means on car audio, I do know a thing or two about home audio. My equipment consists of Krell, Classe Audio, PSB, VMPS (sub) and a 10' projector setup. (http://www.schloctar.com/pictures/theater/DCP_0601.JPG)

As for 15" drivers being slower than 12" or 10" drivers, it isn't a myth. It's simple physics. A 15" driver has more surface area and mass than a 10" or 12" driver. I'm sure there is no argument there. In a sealed box, it has more resistance to travel than a smaller driver because of the increased surface tension area. While it is right that a 15" driver can produce a continuous tone every bit the same as a 12" or 10"; the difference lies in the transient response times. That is where the "sluggish" or "muddy" sound comes in. Yeah, cars are anything but a perfect environment for audio, so I do think a grain of salt should be observed in most decisions and purchases.

Since I listen to a lot of bands like Rush, Dream Theater, Anthrax, Motorhead, old Metallica and the like, fast bass response is something of a concern. Besides, if any of you have ever used a frequency analyzer on you music, you'd be surprised to find much musical information below 30hz. So real low extension isn't that much of a musical concern as it is a home theater concern.

Yes, I'd love to build a custom box for my vehicle. However I lack the wood working equipment to do so. I have $10k worth of house projects to finish before I can get to even purchasing woodshop equipment. So I'm looking for a reasonable option to use for the next few years till I can do something more "custom".

I do like all the suggestions I've seen so far and it definitely gives me more to think about and plan. I like knowing about options I haven't yet considered or about shortcomings in areas I haven't noticed. I don't buy much on impulse and prefer to research all options first before making a decision. So I'm still open to suggestions and comments. Thanks.

dltf90, Well, I hope that what I have said will help in your decision and not just to persued you. It seems as if you have a very good hand on home systems which can relate to vehicles too. Obviously, just like you stated, vehicles are in no way a perfect place to make a perfect soundstage. That's were all those crossovers and special box designs and all come into play.

Whatever you do, hope it all turns out the way you intended.

if your looking for 12 for sound quality i would have to recommend the punch p3. i own 2 of them and ever since i had a custom ported box built i couldnt be happier. i have not heard them in a sealed box so i dont know what they would sound like. i doubt the quality would decline. just so stang doesnt come back with how shitty my system is i am also goin to recommend the jl w3. i will say that 3 of them is going to be very loud. i have a buddy that had 3 12s in an extended cab dodge dakota. oh my god. that shit was loud. but aside from loud it had some of the best bass responce ive ever heard from a system. truly a quality setup. i know he was running a phoenix gold amp. no clue how many watts. he did it with just one amp though. maybe you could try the 10w3s and a amp with just enough power to get the kind of bass your looking for. i recommend audiobahn amps. i dont have one but i have installed them. i am very impressed. well, hope i helped you out.

As for 15" drivers being slower than 12" or 10" drivers, it isn't a myth. It's simple physics. A 15" driver has more surface area and mass than a 10" or 12" driver. I'm sure there is no argument there. In a sealed box, it has more resistance to travel than a smaller driver because of the increased surface tension area. While it is right that a 15" driver can produce a continuous tone every bit the same as a 12" or 10"; the difference lies in the transient response times. That is where the "sluggish" or "muddy" sound comes in. Yeah, cars are anything but a perfect environment for audio, so I do think a grain of salt should be observed in most decisions and purchases.


yes, it is a myth

Yes in a sealed box a sub with a larger cone WOULD have more resistance to movement because of the increased change in pressure, but you're forgetting one huge part of that argument....you put it in a larger box. The resulting change in air pressure is very similar to a smaller sub in a smaller box. The response of the speaker to a given impulse is defined by the Q of the speaker/box setup. If you've ever even dabbled in the effect of the damping ratio on the transient response of second order systems you'd know this.

And if you don't want to believe me:
http://www.adireaudio.com/Files/TechPapers/WooferSpeed.pdf

or just do a search on any car audio forum on the net

yes, it is a myth. Yes in a sealed box a sub with a larger cone WOULD have more resistance to movement because of the increased change in pressure, but you're forgetting one huge part of that argument....you put it in a larger box. The resulting change in air pressure is very similar to a smaller sub in a smaller box. The response of the speaker to a given impulse is defined by the Q of the speaker/box setup. If you've ever even dabbled in the effect of the damping ratio on the transient response of second order systems you'd know this.

I have no desires to get into a flame war, especially on so subjective a debate as this. I agree, box types and sizes can have a very pronounced affect on performance. Just the same, what I stated is also equally valid. There are two differing positions on this, neither is right, neither is wrong. Audio is as much voodoo as it is science. People can hear things differently whether it is real or not.

In my case, I have my own empiracle observations that I draw upon to give me the conclusion I have over very large drivers. While not the best parallelism I have, I do remember demonstrating my theories to several of my friends when I was shopping for speakers about 8 years ago. I was thinking of getting either the Paradigm 7se or the 9se speakers. The only difference being that the 9se had an 8" and a 6" where as the 7se had two 6" drivers. CD after CD were demo'd and the same conclusion was reached by all. While the 9se had deeper bass extension, it sounded muddier and less detailed than the 7se with its smaller drive array. It has been very hard to break me of that philosophy ever since.

One pattern I do see is that my idea of the 3x 12" system is going to be overkill for my needs. I may need to be looking into a smaller sysem with perhaps a less than fancy, custom box. I don't know where to get one since the local shops in my area tend to cater to rich teens and wanna be thugs. Those places make me kind of uneasy.

And it's not possible in any way that the 8" driver wasn't in a well-matched enclosure? Or maybe it wasn't designed as well as the 6"? Or maybe you were interpreting a more well rounded low end as a muddy sound? If the speaker cuts off at 60hz it will sound more "snappy" than one that cuts off at 40hz, just because that extra low end tends to blur the higher pitched "attack" that you have on kickdrums. I mean you're taking one specific example and jumping to this HUGE generality that encompases every speaker of different size....just imagine if your "test" had a different outcome. Maybe the dual 6" speaker sounded distorted on low notes and the 8/6 hybrid had a very solid low end, and then jumping to the conclusion that no 6" can play low, or a larger speaker can always play lower than a smaller speaker. You know how ridiculous that sounds right?

And yes I agree, 3 12's would most likely be too much, not to mention a huge waste of money. If you want a "tight" sound then stick with sealed, the higher group delay of ported, over emphasized low end, and sacrificed top end will take away from this crisp sound you're looking for. I say one sealed 15, but if you have a personal problem with 15's then a pair of sealed 12's. Just keep in mind if you go that way you're going to be spending nearly twice as much money on the subs, and nearly twice as much money on the amp, with a very very small increase in output vs a single 15. Brands to look at are Adire, Image Dynamics, Arc, and Ascendant Audio.

Yea man were not trying to start an big argument what so ever. It is generally assumed that 15's and 18's are more sloppy, but in the case of most audiophile level products this just isn't the case. Where are you located? It may be possible for you to hear some single sealed 15" setups using brahmas ect....

Yea man were not trying to start an big argument what so ever. It is generally assumed that 15's and 18's are more sloppy, but in the case of most audiophile level products this just isn't the case. Where are you located? It may be possible for you to hear some single sealed 15" setups using brahmas ect....

Barberton, Ohio is a small town (60,000 people) just outside Akron. We call it Barbertucky because of the high concentration of rednecks. I think I found a shop that caters to the high end and not the SPL/Attention seeker crowd. I'm going there to see if I can get a better demonstration.

I'm 33, and therefore I'm kind of set in my ways. It is hard to believe there are 15" drivers that provide fast response. But then again, much could have changed in drivers in the 10 years since I last heard them in cars. None of the car installers I knew back then would touch them unless they were going for an SPL contestant vehicle. The one really difficult trick with car audio is getting solid mid-bass.....

it used to be that large drivers were a lot more sloppy .... but things have changed a LOT in the last 10-15 years. We used to have to go isobarik on the enclosures to keep them at a reasonable size, now a high powered 15" sub can live in a 2.5 ft^3 box. The old speakers had VERY tight suspensions (almost like IB type speakers), the newer styles use smaller boxes but need a lot more power. What brought this on was the availabilty of power - used to be (maybe 20 years ago), only a Bill Gates could afford a 1500-2000 watt car amp - now most any high school kid can afford one. Before you dismiss a 15" sub, try and listen to one of the ones they are talking about (RE XXX, adire Brahma, JL W7, etc ...). The only thing is, you need to cross them low (like 50-60 Hz), so you will probably need a midbass driver too. A good set of say 8" woofers in the front.

I know its a little far away, but if you aren't buisy you should try to come down to Cincinnati May14 (?right Noah) for the caraudio.com meet. You can have a chance to hear some good setups installed by people who actually know what they're doing. I know for a fact there will be a brahma or two there and there should be a decent amount of SQ systems with 15's.

Before you dismiss a 15" sub, try and listen to one of the ones they are talking about (RE XXX, adire Brahma, JL W7, etc ...). The only thing is, you need to cross them low (like 50-60 Hz), so you will probably need a midbass driver too. A good set of say 8" woofers in the front.

That would be an issue, there isn't a lot of space for an 8" driver in the front. At least not without some more extensive modifications. I'm 6'3", so I'm limited on space to begin with.

I know its a little far away, but if you aren't buisy you should try to come down to Cincinnati May14 (?right Noah) for the caraudio.com meet.

That's a good idea, unfortunately that's my birthday. I plan on being otherwise occupied on that day. However here have sold me on the idea of looking for places that will let me "test out" different sub arrangements in my car before purchase.

On another note, I was able to get my head unit installed today with the help of a friend. Pain in the arse too because of the brain unit. It sounds leagues better than the previous Pioneer Premier cd HU. You need a very good subwoofer setup since DVD-a has so much more detail at 24/96 or 24/192. I noticed my current lower quality sub system sounding a lot more detailed than before.

Unfortunately I couldn't get much else done today because of the freak weather. I know my current bass amp has the input level too high, I'll have to tweak the amp in the morning. I also need to find out how to disable the parking break / no video safety. Not that I'll ever watch a vid in a moving car, but it also prevents access to DVD-Audio menus which is a pain in the neck.

Lastly, I found someone to create a custom fiberglass housing for my center channel speaker. It will sit on the dashboard in a pod covered with the same vinyl as the dash. I'll lose the dash clock in the process, but that's a smaller price to pay. Should look really cool.

I glassed an 8" woofer into each door where the 6" door speaker used to be. Those are my subs ..... so I didn't give up any space, in the interior OR the trunk

Yeah, usually when dealing with large coned speakers you usually have to put much more time and money with the front stage. If not, the system will sound too bass heavy in the rear and too weak in the front.

So you put together a system and has a pair of 18's and a amp to run them. Then you find that you have to shell out at least $300 just for a pair of strong componets. Oh, don't forget you need to amp the componets too. Most people just don't have the $$ for all of that.