Pro's and Con's

[chad y 1]

ok I am looking for opinions here. what do you guys feel are the advantages and disadvantages of running several 8" subs compared to a single 15". Asuming both are installed properly and run off the same amp at the same impedience.

Thanks

Chad

[johnecon2001 82]

Depends on the Goal really. Advantages could be smaller box depending on the subs if you choose 8's over a single 15".

It's all woofer dependent though, so tell us what you're thinking of.

[chad y 1]

I am not sure really. I was just thinking of different installs I would like to try. I have a TC 3000 15 DVC 2 in my truck now. but I am always looking....lol

I am open for suggestions of pos. combos

Thanks

Chad

[johnecon2001 82]

Depending (again) on how many 8's you go with and which 8's they are.. you might end up with more cone area than the 15".

There are too many variables to shoot you a straight answer man. Find out how many 8's you're thinking of and which ones, and we can try this again.

[nstaln 0]

You have to consider the nature of each type/size sub. The 8s will usually yeild a slightly higher frequency response and some people consider them to be "faster" if there is such a thing when dealing with subs. Even if you end up with the same cone area the 8s will have more motor strength per/surface area than the 15. The 15 will usually go lower easier because it has so much more cone area to reproduce low frequencies. As someone else stated there are too many variables to make a definitive call. However it has always been kind of a rule of thumb that multiple drivers usually won't sound as good as a sigle driver. There is always the cost to consider, most multiple sub setups will cost more than single sub setups. I considered going with 4 8inch SoundSplinter RL-i subs with 250rms each and .75 cubes each, for a total cost of roughly $800. Instead I went with a single TC Sounds TC3k 15 in 2 cubes with 1k rms for a cost of about $500. So I saved myself $300 and a cube of airspace and I feel the 15 gives me a lower response in my SUV than the 8s would have. That's just my opinion though. P.S. I have some pics of my install posted in the "install logs" section under TC3K 15 install pics.

[JimJ 11]

and some people consider them to be "faster" if there is such a thing when dealing with subs.

Then those people are wrong/aren't listening to properly-installed setups...

The 8s will usually yeild a slightly higher frequency response

Pretty much useless for subs, as ideally you'd be crossing over at 60Hz or thereabouts anyway...

However it has always been kind of a rule of thumb that multiple drivers usually won't sound as good as a sigle driver.

From who?

If anything, for subwoofers I'd say the opposite...but it depends on what kind of linear travel is needed to get the desired output...

[aznboi3644 2]

However it has always been kind of a rule of thumb that multiple drivers usually won't sound as good as a sigle driver.

Lol where did you learn about this "rule of thumb" and who's butt was this thumb in??

[shizzzon 461]

i've never heard of multi drivers are worse than 1 larger one.... time to get the facts straight in this post, hehe

Ok, surface area for a 15 should be around 176.7 sqin

It would take 4 8s to reach about 201 sq in. Now, that means 4 8s may have more cone area, but 4 8s probably will not be able to take the amount of power 1 15 can take. Also, depending on the 8s, their maximum excursion may not be competitive to a single 15 either.

8s also tend to get their best performance at 1.0 cuft ported whereas 1 15 usually should be at 4cuft ported.

Now, this means that you may have to build a larger box because you will probably need more than 4 8s to compare to 1 pretty decent 15. Now, if you build a larger box, then compare that box to a box larger than 4cuft for 1 15 as well... The box for 1 15 will now be more efficient and power handling may decrease only if you do not properly crossover the lower and higher frequencies properly to prevent over excursion.

So basically in my opinion, you need to find 4 8s with their summed rms rating greater than 1 15 that you are comparing to and this will be hard!

If you are comparing to 1 15 at 1000wrms, you may need 4 8s 300wrms...

And like someone else has already said, it's an 8, pay attention to the playable frequency range because it may lack low end response.

[nstaln 0]

Let me clarify...a single sub system WILL be more linear than multiple subs coupling with eachother...it's physics...a single sound wave as opposed to two waves acting as one. I'm not saying it would be louder. This sentiment has been echoed by some of the top names in sound(Tom Nousaine, David Clark,etc.) So I quess those would be the butts. As far as frequency response goes it all depends on what you are trying to accomplish from the sub system...you can usually crossover 8s higher than a 15. I've heard 8s crossed around 80-100 down sound very clean, most 15s I've heard including mine seem to like being crossed lower(mine at 60 down), because 8s can usually render those frequencies better than big drivers. Of course these are all general theories, since we are not comparing apples to apples. I agree that the "faster" idea is folly...many perceive higher bass frequencies as being faster response which is false. They are being produced faster because it is a faster frequency but it doesn't make the sub "faster". There are too many variables to be talking too many "facts", however physical principles will always apply. No one ever said that multiple drivers are "worse"...but coupled soundwaves will inherently be less "clean" (even if it is only theoretical and audibly inperceptible) than a single soundwave. If all things were equal with the 8s and the 15, same xmax, same response, etc, then it would simply be a matter of cone area. But as Shizz's response states quite clearly the comparison is not equal. Which further proves the point that multiple small drivers will have a generally harder time reproducing lower octave soundwaves than a single large diameter driver at the same magnitude.

Honestly you will not really hear a difference and as far as bass goes. I myself would rather have 4 10s than the single 15...because you won't hear the linear difference...but you will hear a difference in output. But I could not afford the extra drivers, could not give up the airspace, and lacked the power needed to drive the subs properly. Again I was stating generalities

Edited February 17, 2008 by nstaln

[shizzzon 461]

i believe the term"faster" that you are referring is "Group Delay."

The lower the group delay, the less muddy the bass sounds.

A subwoofer's transient response is effected by the group delay.

The lower the group delay, the quicker a sub can recover from one frequency and start playing the next one.

Of course in ported boxes, group delay is a LOT higher than sealed, this is why sealed sounds so controlled.

[nstaln 0]

i believe the term"faster" that you are referring is "Group Delay."

The lower the group delay, the less muddy the bass sounds.

A subwoofer's transient response is effected by the group delay.

The lower the group delay, the quicker a sub can recover from one frequency and start playing the next one.

Of course in ported boxes, group delay is a LOT higher than sealed, this is why sealed sounds so controlled.

Which is exactly why the size of the driver as it pertains to being "fast" is irrelivent. As you stated it's a matter of alignment and usually has a lot to do with the power and filtering applied to the sub system as well.

[///M5 2,833]

I think it should have been left as you can't compare the two without being more specific.

[chad y 1]

Ok I was looking at (6) AA Assassin Series 8"D4. so what do you think?

Thanks

Chad

[///M5 2,833]

and the single 15 would be a?

[chad y 1]

I currently have a TC 3000 15 DVC 2

[subwoofery 0]

Probably the TC-3000 he already has. Might be wrong though lol

[johnecon2001 82]

I'd guess the 6 8's would be louder in an optimal ported box than the 15" TC3k.

Cone area ftw.

[Aaron Clinton 2,372]

There is some good discussions in this topic.

[chad y 1]

yes there is alot of good discussions going on.

Here is what I was seeking though.( I may have stated it wrong in my original post. I was just referring to 8's and 15's but it could be any combonation)

What I was looking for and I believe (Nstain) sorta touched on was what do you prefer and why?

I am not asking which is louder or lower or can handle more power ect....(but that maybe why you prefer one over the other and thats cool)

I have had

2-8's

2-10's

2-12's

1-12

1-15

I have had them in different combonations (vented,sealed,bandpass)

So here is my question what set up do you prefer and why?

Thanks

Chad

[shizzzon 461]

what setup do i prefer? What i can optimally fit in the space i have to work with.

If i had a van, i'd fill the whole thing up, honestly.

[nstaln 0]

As much as I would love multiple drivers for crazy output....realistically I prefer(and have) a single 15, sealed, with lots of power. A 15 because it reproduces lower octave frequencies better/easier(hopefully I won't get jumped on again for that statement), sealed for less group delay(not "faster" thank you for the correction Shizz), and lots of power(power=control). Complimented by some strong 8s up front...makes for good sound.

Edited February 18, 2008 by nstaln

[shizzzon 461]

sadly, i've never had the time to do a nice clean Sq setup properly.

But the good thing is, the older i get, the more i see in the future that i will later on in life, just not right now.

[Jpm4536 0]

Gotta remember every time you add another driver you pretty much double your expenses... The 6 8" subs might be cooler than the single 15 but is it 6 times as cool?

[subwoofery 0]

If it was me, I'd choose the 8s just for the HOLY ...T factor.

6 x 8s moving at the same time and putting pressure on someone's ear is the S E X.

[///M5 2,833]

I have not ever much thought about it, the trick for me is always to get enough midbass the sub-bass is teh easy. A single 8" driver can overpower most people's front stages