DIY subwoofer

[Joe Camel]

Could this be done? Basically I just want one or two speakers that all the bass goes to. Oh, and for my surround sound, not my car.

[Alamo]

What kind of speakers you got or are you asking if you can make speakers? How do you plan on hooking it up and whats your power available?

[Joe Camel]

120w amp, and some 8" pioneers. I just had them laying around. I suppose I'll just hook it to my amp.

[Craigslist.org]

A video tutorial is always easiest to follow. If this isnt what your looking for try a youtube search.
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[MunkeyQ]

Handy hint: check out my epic subwoofer sticky in Gearheads. It's written for cars, but the cabinet design stuff still applies.

I'll write a proper reply later.

[HLC]

I figured a quick google search would turn up lots of 8 inch enclosure plans, but I was wrong.
It seems finding plans online is difficult, so I'd suggest you run down to your local library and see if they have some books with plans.
If you can cut and saw wood, it's easy.
But having tried and true plans helps.
There are optimal dimensions that work best.
Pioneer may have specs online that tell you the recommended enclosure size.
Just make a box with the recommended volume (L x W x H ).

You'll need a saw(s) that can cut a straight board and also an 8 inch circle (or two) in a board., a drill and a screwdriver as the main tools.
If you can find the specs for the drivers, that would let you fine tune the cabinet, but published plans for any 8 inch drivers will probably sound decent enough (more win than fail).
I'm not too sure what to suggest if you decide to put both 8 inchers on the same front board (making only one enclosure).
My guess is you may have to expand the dimensions a small amount to make up for the lost volume the second driver is taking up, thus still keeping a similar volume for the drivers (not doubling it).
You also have to feed them only the low frequency signals, either by the amplifier doing that or by filtering out the highs with a crossover.

[Joe Camel]

You also have to feed them only the low frequency signals, either by the amplifier doing that or by filtering out the highs with a crossover.

This is my main problem. What's a crossover?

[HLC]

If your amplifier doesn't have a subwoofer output, then you'll want to keep the higher frequency sounds from getting to the subwoofers. If you have more than one amp, an active crossover like this may be all you need, placed between the source and the amp that drives the subwoofer :

http://www.mcmelectronics.com/product/PYRAMID-CR65-/60-3950

++++++++++

If all you have is the 120w amp, you'll need that amp to drive both low and high frequencies.
But you don't want the highs to get to the subwoofer, so the easiest way is to choke them with an inductor. It's just a coil of wire placed in between the speakers and the amp.
The best ones are just copper wire, but it takes so much copper the cost of copper raises the price.

http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=255-444&DID=7

http://www.mcmelectronics.com/product/AMS-ENTERPRISES-50-3037-/50-3037

If you can get your hands on enameled copper wire, you can wind your own.

The cheaper route is to slip some iron into the copper windings.
Audiophiles don't like this method as much, but I doubt you'll really be able to tell the difference.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=266-572

http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=255-120

+++++++++++

I sort of guessed your drivers are 8 ohm and you'd want to keep out the frequencies above 200 hz. (standard middle grade subwoofer numbers).
I used this link:

http://www.carstereo.com/help/Articles.cfm?id=2

which calculated 6.0mH coil would give a cross-over frequency of 212 hz.

So I looked for 6.0 mH inductors.
You can get smaller ones and save money, but not choke as much of the highs.

++++++++

Another route would be to get an amp that has subwoofer outputs and then use that as your primary amp.
Split off the signal there and send the higher frequencies to your 120 w amp.
It'll do the crossing over internally with integrated circuits, which cost pennies compared to kilograms of copper.
The savings will result in an internal electronic (active) crossover plus another amp.
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