I dug some old 10" JL Audio subs out of the attic that I had installed in a truck back in the late 90's. I plan to install them in my 99 extended cab, but was wondering what I should power them with.. Unfortunately I don't have the specs on the woofers, other than I do recall that they were the one's designed for low-volume enclosures.

I also have a similar woofer in a 12". Seems such a waste to not use it as well. Any advice on a enclosure for two 10" and one 12" sub, as well as what amp? I'll most likely just stick with the two 10's, but would like to use the 12" as well, granted I have room...

THanks,
JOey

 

Do not amp all three speakers with the same amp, and don't include all 3 in the same enclosure if they are sharing the airspace.

I'd start out with planning around just putting in the two 10's. Try to find a serial number or any kind of mark on the subs basket or magnet to find out what model they are so you can get specs to find out what amp would be best.

 

Older JL 10's eh? Run no less than 500Wrms. Here's why. In setting your gains, you will easily be able to hear woofer distortion long before amplifier signal clipping. A subwoofer's power rating is matched not only to it's thermal limits, but it's mechanical limits as well. Even if your subs are rated for, let's say 100 watts RMS, and you get a 500 watt RMS amplifier, that doesn't mean your amplifier will be putting out 500 watts ALL the time. If you set your gain correctly, then your amplifier should actually run nominal 200Wrms or so.

As for your 12" woofer, I have played with just about every combination of amplifier/subwoofer setups that you can think of. I had two 8" woofers and a 10" woofer hooked up to an amplifier, two 10" woofers and a 15 hooked up to an amp, two 12's and a 15, two different pairs of 10's, sealed and ported enclosures connected to one amp, you name it I did it. There's actually a very fine science behind doing that, a science that means you need to understand how much power is going where in terms of voice coil loads, power handling, yada yada yada (assuming your woofers would be in properly-designed enclosures). Now, I am not going to condone the same acts, I did it when I didn't know much and I was still learning and experimenting. But if you do decide to run your 12" subwoofer and two 10's, make sure you carefully calculate their impedance loads to identify how much power they are recieving for the sake of your equipment, and don't install the 10s in an enclosure with the same air space as the 12" woofer because they WILL interfere with eachother. Electrically, electronically, thermally, and mechanically speaking, you can NOT do any harm to an amplifier, your 12" subwoofer, or your 10" subwoofers if they are all loaded to one amp AS LONG AS their combined impedance is within the handling of the amplifier, and your amplifier's power is distributed to all 3 subwoofers not to exceed the highest-handling woofer, and you compensate power distribution in case of a difference of voice coil loads. Basically, experiment at your own expense! Even if you do experiment, you won't blow anything up. It'll just be a lesson learned!!

Now, the proper way to use your pair of 10s and your single 12 is to give the 12" a box that doesn't share the same air space as your 10's, and use two amplifiers, one for your 12 and the other for your 10s. Honestly, that would make for quite the installation!

 

^^To sum up that essay, just grab an amplifier rated for 400-600 watts rms @ 2 ohm and set gains appropriately. The power handling of the subwoofers will actually depend mostly on the enclosure you put them in. This is assuming the 2 10" subs are single 4 ohm impedance which many of those older JLs were.

Dont use 2 10s and a 12 unless you have some major processing and can have them playing separate bandwidths off different channels of amplification. Otherwise it will sound like ***. Just use the 2 10s.

 

Thanks guys.. I'll probably just go with the 10's. I was considering having the 12 in a different enclosure. Sounds like I need to keep my eyes open for a 500-600 watt amp..

 

The judgement of a bass system "sounding like ***" because of different subwoofers is quite subjective, and far less the issue when you have low-power drivers of relatively close diameters of possibly the same models. Now, I can see this being point if someone had, per say, a pair of JL 10W7s and a single 12" Rockford P1. I highly doubt this guy is as sensitive to his audio as some of us are, and to your average Joe having his dual 10s and single 12" setup would be fine UNLESS he cranked the hell out of the volume. There are some people who try to pull 120hz through their 8's, then you have others who try to pull 120hz out of an 18".

 

T/S parameters for same brand/model subwoofers of different diameter size are hardly ever the same, and they will never sound or perform the exaxt same. This is true even of subwoofers of the exact same model and size since many companies use asian buildhouses with poor unit-to-unit consistency.

Plus IME anyone who is putting subwoofers of different sizes in just to put them in is obviously looking to "crank the hell out of the bass" as you called it, and like what you said (and what I originally said), it will sound like crap.

 

You are totally right on that point, in fact on paper there are no speakers of different sizes but identical make/models that are identical. However, to some people, it's 'close enough'.

And people putting speakers of different sizes more than likely are (like you said) looking to crank that, at least that's how I was when I was in my total basshead phase just looking for attention. But when I really got curious, I began experimenting as a means of answering questions, not just to turn heads. Even at a nominal listening volume, the OP's 10s and 12" with a single amp *could* sound quite clear if installed in their own enclosures. I've heard different sized woofers on one amp sounds pretty good given they were driven with more than enough power and enclosed to their own specs. I mean when you think about it, some people will upgrade their system by simply changing the subwoofer and box, and nothing more. Not even tune the crossover to a lower frequency with a larger woofer.

I'm not condoning or even justifying the kind of system in question, what I'm saying is to some people, it won't sound bad at all because realistically, some specs are so close that some people can't tell the difference. Also, it doesn't really hurt anything to experiment (except electronics components when clipped or misloaded, something common with proper setups). If anything, it just gives a platform to base sounds on what is and isn't good sound..