binelus

Is it preferable to have 2 12 inch subs or 1 15 inch sub for sound system ?

Wide LS

depends which 12inch or what 15inch speaker and what amp too. Also the more speakers the more trunk space is needed. I like alot of bass so I went with two 15's

Toysrme

15's are only good for SPL (loud).
Get two 12's for a balance, or 2 10's if you want sound quality...

thank god the sale of 15's is delcining. 99% of the sound quality is in the installation & box; however 15's just never responded quick enough for me...

binelus

I was about to buy an Andiobahn 15 inch sub with the JBL1200.1 amp. Thinkin if it's a good set up.

GaryDell

The two 12's have about 25% more cone area, or less than 1db SPL advantage. Sound quality should be identical. Go with whichever is cheaper (most liekly the 15"). Cone area makes essentially no difference in sound quality. You can verify this with the article regarding inductance over at adireaudio.com.

I'm not a big fan of Audiobahn, though...

And where did you get your information that sales of 15's are declining? Do you have some sort of official report where a significant amount of speakermakers shared sales information for no particular reason, or is this what your 18 year old friend working at Mobile One told you...

NoRyceGS4

dude, dont bag on us younger guys.

theres nothing wrong with audiobahn. i have heard everything from JL's 12w7 to Audiobahn's 1208T. though the w7 is better, unless youre an audiophile you wont really care. i just purchased the 1206T myself. from my experience at car shows, street shows, etc. ive noticed that MOST 10's will not hit as low as a 12 or 15, so if you listen to alot of that lowbass stuff (im assuming you do, 1200/1 amp isnt exactly for the normal bass savvy person) i would go with the 12 or 15. i was thinking of going with 2x15's myself but i wanted to have SOME trunk room.

jmecbr900

I don't agree with your assesment.

The SPL advantage will be very dependent on power and speaker. Even kept to the same brand, its still very dependent on power. Since most amps double their practical power when impedence on the spkrs is dropped, it would also stand to figure that you could theoretically put more power to 2 12's MOST of the time from the same amp when compared to the single 15. DVC's are a slightly different and can possibly level the playing field a little more.

In regards to sound quality, the smaller speaker will have an advantage due to being able to have less mass/area to move during music transients that are always present in music. This will make the bass notes sound sharper and more realistic as opposed to simply boomy.

If I had to choose from only those two choices, I would definetly opt to go with the 2 12's because it offers the best of both worlds. Better SPL and sound quality possibilities.

This is assuming that I also wanted to give up most of my trunk. If not, then the single 15 would be the choice simply because of the amount of room needed is usually less.

RMMGS4

iTrader: (5)

I pretty much back up what jmecbr900 said.

Given everything else being equal except size, a 15inch can't match the speed of a 12 because of it's greater mass.

I do agree with GaryDell that 2-12's will have more surface area than a single 15, so again all else being equal, the 2 - 12's will have all the advantages of surface area of the 15 and more, but at the same time play tighter and more defined.

Again, I will repeat "All else being equal". This does not mean that every 12 can beat every 15. There are way too many variables to offset the advantages being discussed. Also a well designed 12 can play down to below 20Hz, so a 15 has no significant advantages with playing better in that area. The key advantage to a 15 is the ability to play louder, and do it more efficiently, but again 2 -12s vs 1 -15, it's gonna be close depending on what brand, models we are talking about.

So that's my input if we are talking speaker theory.

If anyone wants to compare brand x speaker vs brand y speaker using brand z amp, I'm sure you'll get a lot of different input on that subject.

GaryDell

"The SPL advantage will be very dependent on power and speaker. Even kept to the same brand, its still very dependent on power. Since most amps double their practical power when impedence on the spkrs is dropped, it would also stand to figure that you could theoretically put more power to 2 12's MOST of the time from the same amp when compared to the single 15. DVC's are a slightly different and can possibly level the playing field a little more."

This is no advantage either way. It's simply a matter of purchasing the proper amp/sub combo. If he can't get the 15" driver that he wants to result in a 2 or 1 ohm final load, then yes, go with the two twelves. I only recommend this because he wants a lot of power and there are very few class D amplifiers that put out max power at a 4 ohm load. But if he can get the 15" he wants to result in a 2 or 1 ohm load (DVC 4 ohm, SVC 2 ohm, etc...) then go for it.

Your comment on amps generally doubling power when impedence is halved obviously only holds true to a certain point. Sure, the JBL will put out twice the power at 2 ohms as it will at 4 ohms, but if he plans this out properly, he shouldn't have anything to worry about.


"In regards to sound quality, the smaller speaker will have an advantage due to being able to have less mass/area to move during music transients that are always present in music. This will make the bass notes sound sharper and more realistic as opposed to simply boomy."

Again, NOT TRUE. How subwoofer's ability to smoothly change the frequency being played is simply a matter of inductance not Mms. So often I hear people say that 15's are "slower" than 10's, yet if the cone truly is moving at a slower velocity on a 15" driver than a like 10", then the 15" is playing a different frequency! A higher Mms simply lowers Fs...

Please refer to the following link before posting counter argument: http://www.adireaudio.com/tech_papers/woofer_speed.htm

RMMGS4

iTrader: (5)

With regards to your power explanation, yes get the impedance required to get the most output for the amp in question.

As far as the speaker inductance, glad you posted the link. I looked for it before I responded, but couldn't find the article.

At a glance the article does appear convincing, but I honestly didn't post here to get into a debate on speaker theory, since all I am doing is offering to help answer the original question. I'm not here to agree or dis-agree with the article at this point.

So the last paragraph in the article stated " And the greater the inductance, the slower the driver - the lower the transient response." I would say in general that 15's are typically designed with larger voicecoils than their 12" counterparts therefore, the inductance would "typically" be greater in 15's and than 12's. So again I will generalize that most 15's will play slower than 12's.

In my experience, I have found 12's to typically have better transient response than 12's. Whatever the reason, so be it.

My recommendation is 2 -12's will "generally" work out better (sound quality wise) than one 15, if the cumulative efficiency and net impedances are the same. If SPL is a higher priority, then find the best single 15 or 2-12's (within your budget) and whichever offers the highest net efficiency, go for it.

GaryDell

"article stated " And the greater the inductance, the slower the driver - the lower the transient response." I would say in general that 15's are typically designed with larger voicecoils than their 12" counterparts therefore, the inductance would "typically" be greater in 15's and than 12's."

I haven't found this to be true a majority of the time.

"but I honestly didn't post here to get into a debate on speaker theory, since all I am doing is offering to help answer the original question."

Well I think that speaker theory is exactly what the OP was asking for. It could have been left at "two 12's have more cone area", but I don't think that would be sufficient. But I'm glad you don't want to continue going deeper into this topic (at least for tonight) as I have to study for my digital logics test tomorrow, and really need to get off the board.

RMMGS4

iTrader: (5)

Ok get back to your school work, but last thing.

When you say you haven't found this to be true a majority of the time. Are you talking specifically voicecoil size?

To take this discussion in another direction, How many drivers, testing / evaluation have you listened to? Have you done critical listening audiophile level or SPL? In car or home environment or both? The bottom line for me is with all the 15's and 12's I have built, listened to and evaluated, I have found few 15's that could exceed the sound quality of a 12, particularly with regards to transient response.

As far as answering the original post, I gave my advice and so did you. I can see that we could easily get into a long technical discussion , but I think it would be more beneficial for others to chime in at this point

darden

from CarStereo.com...

i do not know the exact science behind subwoofers. but i do often go to my friend's stereo shop show room and play around with all the subs when the boss is not there.

the question is TWO 12" subs versus ONE 15" sub.

i personally have TWO 10" subs. when i compare the way my subs sounds to ONE 15", my bass is definitely tighter BUT NOT as BOOMY.

you should go to the store and compare the same model subs in various sizes. you will be able to tell the diff. between the two immediately. be sure to compare the same brand and model subs with different sizes running on AMPs that will power them at the optimum level and playing same music.

it is my understanding and experience that TWO 10", 12" usually sounds much TIGHTER when compared to ONE 15" sub which sounds DEEEEEEPER and BOOOOOOOOMY.

i personally prefer tighter bass than boomy bass. so i went with my two 10" in an enclosed box.

GaryDell

"it is my understanding and experience that TWO 10", 12" usually sounds much TIGHTER when compared to ONE 15" sub which sounds DEEEEEEPER and BOOOOOOOOMY."

I will quickly say that this could easily be due to improper enclosures. The 'boominess' you hear from the 15" drivers you listen to could be a peak in the 60-80hz range caused by an undersized enclosure. From my experience in shops, I often see 15" subwoofers in enclosures much too small to do them justice.

I'll chime in tomorrow when I wake up around 5PM, or maybe a bit later after I've begun my Friday night drinking binge.

Toysrme

This is how I came up with the 15 would have more SPL...

if the guy is spending the same amount of money one ONE quality, high power 15 & amp that he would with TWO good 12's, he's still driving the 15 harder. Besides... 15's never were good for SQ, they're only good for SPL
Like I said, 99% is in the install...

Garydell, go email Cardomain.com about it...