i have a king ranch and jl audio makes it where u can put a 10 in the front console and a 12 in the back console is it a bad idea to mix subwoofer sizes because i want to do that and also put 2 more 10 in it along with the other 10 and 12 would that be a bad idea??????
thanks

 

horrible idea!!! NEVER EVER EVER EVER!!!!!! mix sub sizes EVER

 

you will end up with terrible cancellation issues. the only time you can every get away with using different sub sizes is when you are running say a 3 way component set and choose to use an 8" sub for your midbass driver (but it must be crossed over to the correct frequency) and then use your larger subs for the sub bass section of the frequency spectrum.

 

rule the same in the home? I have a cross over network made... i have some old tower speakers that take 100 and up and some subs that take 100 and down. I have 2 10 on one side of the room and 1 dvc 15 on the other. am i getting the sound i want? or should i remove one size? I am planning on putting the 15 in my boat if it will fit but not until next season.

 

It is NOT always a bad idea. When properly done it is the best way to go

but it is very complicated and expensive to do.

 

IMHO opinion and those of others, such as Macintosh Labs (Macintosh makes some of the world's best Class A amps), the best low frequency system for SQ with two subwoofers is to band pass one sub across the fundamental frequency of the space you are in, and the other at 80 hz and below.

So for instance, in our Supercrew, there's about 1.5 meters of space dash to back wall, so the wave length is about 3 meters and the speed of sound about 330 m/sec. So the fundamental frequency is 330/3 or 110 hz. So with two subs, the best set up, if you have the crossovers and amps, is to band pass one sub with a center around about 110 and low pass the other at 80hz.

One example that is a recommendation from Macintosh Labs.

For those of you who say never mix different sizes of sub's, assuming they are crossed at the same frequency, please explain to me why in terms of acoustics it is bad to do so if they are producing the same in phase freqs? And if using the set up described above, the band pass from any size sub would help make up for the natural cancellation of the spaces fundamental frequency and it's integers at higher freqs, regardless of it's size, so long it's a size meant to handle low freqs. Doesn't have to be the same size as the low pass sub.

I'm willing to be convinced otherwise.

BSEEAugs

 

its simple physics, every speaker driver has different perameters, in an enclosed area as small as a vehicle, traditional room acoustics are nonesense with sub-bass frequency's, having two different drivers crossed the same is just asking for weird peaks and cancellation, now its alot different if you have one bandpassed higher so say you have 2 15's crossed at 80hz and then 2 8's bandpassed from 80-150hz, that would work, and I've done that before with excellent results. but alot of people don't have the equipment or know how to bandpass like that, I've seen many ask if they could use 15's 12's and 10's in the same install (crossed the same at 100hz) to hit the highs and the lows.... thats what we are talking about and its nonesense

 

great response styx...

nobody was arguing with lab tested data since lab tested data doesnt account for the somewhat terrible accoustics that vehicles have. The space is too small, the materials used in costruction are of too wide a variety, and the shape is never anywhere near ideal. we were definitely speaking to those wishing to build a box or use a couple of boxes in the ext cab/backseat/trunk and then throw in a cluster of drivers of various sizes that were never intended to be used together in the first place. I mentioned setting up a nice 3-way or greater crossover network to take fulll advantage of using multiple sizes of bass drivers to get excellent sound quality. All too often you see people who have no idea what they are doing getting a hold of a handful of subs, say a pair of tens and a twelve, or a pair of eights and a pair of tens, or a twelve and a fifteen, and then building a backyard box to fit all three of them thinking that more is better since thats what they keep hearing - that the more speakers you have the more bass your going to get.

 

I am very much aware room acoustics are different than a car and it's not well said....

And Macintosh Labs doesn't produce 'lab test data' disconnected from the 'terrible acoustic's othat vehicles have" Macintosh Labs is one of the finest makers of audiophile equipment in the world, including auto gear.

http://www.mcintoshlabs.com/default.aspx

Simple physics...okay, stay with me and, being as I barely passed my undergrad in Electrical Engineering, explain your simple physics to me.

Doesn't hold water.

Two properly boxed but different sized sub woofers, say an 8 and a 12, that are in phase and crossed at the same freq, will not cause freq cancellation of the passed frequencies simply because of their size difference, and because they are low frequencies, they will not cause location issues because of the difference in their relative sizes. We're still talking very big speakers here.

Simple physics..only when frequencies are out of phase, such as when there are resonances at the fundamental frequency (which is different in the shower stall vs the car or home because of it's inherent absorption characteristics, and it's wave length due to it's open space), or the signals are out of phase does the SQ diminish because of 'frequency cancellation' as you all first stated.

The fundamental frequency that the F150 resonates at is a function of it's space and the drivers energy. F=c/L , anywhere from 110 to 150 hz depending on the length of the free space in your cab. But that's why one band passes woofers against a low pass, or otherwise EQ's it out with gain, and it's not complicated if you have a proper amplifier, such as my old school Macintosh.

BSEEAugs

 

we are talking about running say an 8 and 15 in proper boxes, both low passed at 80 here, thats obviously not a good idea, your still talking about low passing say a 15 at 80 and bandpassing an 8 at 80-150, which I have done before, and actually recommend given space and equipment, still two different sized woofers are going to have two different perameters, and will both have different frequency responses(and a different phase response), its illogical to use many different drivers to produce a given range of frequency, maybe if you pulled your head out of your "superior product" you would realize that the tread starter is wanting to use two different subs in an install, they could be different sizes, they might be different brand, maybe both, either way its what anyone used to car audio would call ghetto.

 

It doesn't sound like you have a good reason for wanting to toss mixed subs all over your truck, other than "you want to", so just put two 10's under the back seat and be done with it. You don't need more than that.

 

thats what i was wanting to do where can i get shallow mount speaker boxes to put under my back seats because i am gonna get 2 10's pioneer shallow mounts

 

Sorry styx, wasn't trying to pull a 'head out of your....' comment from you.

Just want detail on why you said it's simple physics. I just think you are wrong if you meant this in terms of freq cancellation and the first post was inre a 10 and a 12, and then brett's was 2 10's and a 15. NO 8 vs 15.

South stated you'd get 'terrible cancellation' which just isn't true if properly matched and boxed, and you agreed with him it was simple physics, then sound responded with an ad hominem about 'labratories,' mistaking my Macintosh labs comment for some kind of disconnected audio laboratory. I wasn't bragging about Mcintosh, simple pointing out to South he obviously didn't know who they were.

I think we both agree that mixing sub sizes is not easy or preferred.

I'll leave it at that.

PhysicistAugs

 

The thing is when most people talk about mixing sub sizes, they are thinking they are going to run say a couple 10's and a 12 low passed in the same frequency range, which obviously is not favored. We come in and start talking about bandpassing one and low passing the other and yadda yadda, which is true, but not what the original poster was asking or planning to do.

So, for most of the people coming on here and asking, NO, its generally not good in the way a lot of people would go about doing it.

If you know what your doing, then yes go for it if you want, but if you know enough to do it right, your not going to be coming on F150online asking about it.

 

How about just 10's in all those locations? Or did you already buy the 12? Three or four JL 10" woofers should be loud enough to cause hearing loss ...which it sounds like is your goal.