Author Options:

Subwoofer Car Amp And a whole lot of mess? Subwoofer and amplifer crossover? Answered

Hi, today what I'm trying to ask is how could i get a car amplifier working in a household environment (i know how to get the PSU going and that side of stuff)

My question is what sort of box will I need for the sub woofer and how will I wire it up will i need a crossover if so can you guide me of what to buy
anything I should know before I attempt this will this work or am I just atempting something that will end up in a mess?


The JBL you are thinking of using is a dual voice coil speaker, which is perfect for this application. JBL's website has the PDF, which includes reccomended boxes for optimum sound. It shows a sealed box volume of 1 CuFt or a vented box of 1.75 CuFt. The box you show is 1.5 CuFt. Close enough for good bass.

You can use a standard stereo amp for this setup to drive all the speakers.

A quick online calculation shows you need an inductor of about 1 mH to achieve a crossover of 300 Hz for the 2 ohm voicecoil. Parts Express shows a typical 1 mH inductor suitable for your purposes. To wire them up, (for each channel [L,R]) take the speaker lead positive (+) from the amp to one side of the inductor and then connect the other side of the inductor to one of the positive terminals on the subwoofer. Now from the first side of the inductor, connect the positive wire for the main speaker. For both the sub and main speaker, tie the negative (gnd or -) wires together and wire them back to the amp. Don't worry about the main speakers not being part of the crossover, you'll want as much range from them as possible. If you use a pair of full range car speakers like 6X9 or 5X7 coaxial speakers in appropriate boxes, then you'll have it made.

Perhaps an 'ible is in your future?

Good luck,


First things first.

What is the make and model of the amp? What is the make and model of the subwoofer? Will the amp be dedicated solely for driving the subwoofer or will it be used to drive the main speakers also? All of these questions need to be addressed before giving good, solid answers.

Now for the generalities.

Look up the subwoofer on the manufacturer's website. Many have suggested box types and sizes listed. If not, at least get the minimum specs of Qts (Q total system), Fs or Fo (resonant frequency), and Vas (equivalent volume). Also, the size may be needed (6.5", 8", 10" 12", 15', etc.). With that info, I can calc a box size for you (sealed, ported, bandpass, transmission line).

If you are using a dedicated subwoofer amp, you most likely already have a crossover built into the front end of the amp. Just plug the wires in as per manufacturer's instructions.

If you are using a general purpose amp for both the left and right main speakers as well as the sub, you'll need a crossover. Check at MCMElectronics.com or PartsExpress.com for a pair of crossovers of appropriate wattage and a bass crossover of between 200 and 500 Hz. You would then need to use 2 subs, 1 for each channel.

That's about all I can give without more info.


Thanks I now know how to do it now, I am not 100% sure what speekers i need to buy as i don't want to over power the sub-woofer or not loud enough .although this is going to be on hold for a while, because i am low on funds I'm going to make some plans and occasionally buy a few bits do it I will still get round to it :)



Do you think they will all work? together also what amp would i need in watts


That is the sort of speeker im thinking about buying and also the enclosure is :


is that right?

if so all i need is an amp and crossover + 2 speekers if im right?


I'm not going to be using this in a car.
This project is for good sounding cheap home made speaker system, if you know of any other way of doing this please say.
I preferable want it already enclosed in a enclosure as it will be easy-er and better looking. If I need to I will buy an enclosure the sort of speaker's. I'm thinking about buying a 6-12 inch size does not really make a great deal of difference. However I don't want to have a giant box (more than 15 inches all enclosed). The other 2 speakers are needing to be quite loud so there not over powered by the sub please recommend a good sort.
As I don't have any of the speakers amp or crossover for it at the moment.
how do i wire up the whole lot what I mean by this is What sort of crossover and amplifer do will i need and how much will it all cost in total

I am imagining that i will need a crossover as I want to be able to use the speakers bass side of it and it to be really loud.

Thank you daniel