Page 1 of Has anybody built a DIY Subwoofer

like most people i would love a meety sub to go with my home cinema
set up, but the cost of a decent one mind blowing.
I have a kenwood 5050 amp with a sub pre out on the rear. Therefore the sub would need to be active.
my idea was to get a 12 to 15inch driver and mount this in a sealed MDF box, amp this with a car audio sub wooffer amp. This should then have all the required inputs, crossovers stc. I would use a 12v to mains adapter to power the amp.
has anybody done this? does this sound feasible? will the line feed be at the right frequencys etc?

any experts out there, your advice would be appreciated

Hey bifter.
I`ve built loads of car sub boxes, its not to difficult at all, what you need to know is the what volume box your sub needs, usualy measured in litres and whether it needs to be ported or sealed.

If you are going to use car subs don`t forget they are 4 ohm or 2 ohm bridged (connecting 2 subs together) , home cinema are usualy 8 ohm but should not cause to much bother. I usualy use Alpine or Kenwood subs as reasonably priced, and not bad performers they also list the volume in the brochure

three quater inch MDF is the best stuff to use make sure it is air tight with silicone and line the box with loft insualtion. you might find it cheaper to buy an active sub though
your looking at £50 for a decent sub £20 in materials £20 for good speaker cable, £150 for a good amp and probably £50 for a 12v transformer don`t forget most amps need 14.4 volt and 40 amp plus to run properly. a lot of wires and messing around. but not impossible.

Good luck, let me know how you get on.

This item was edited on Monday, 21st October 2002, 16:56

was`nt looking to spend that much, im not a true audiophile, I just want some rumble under my arse when the dinosaurs come etc.
plus peek volume is not a issue as the neighbours might have something else to compain about.
I have a Maplin catalogue, you can get drivers for about 30quid, amps for about 60quid and so on
hhmmmmm

Or will these just sound crap?

I am sure Alpine do a 12" and a 15" flatpack that you build yourself it comes with all the bits so you may save a bit.

But as Gerald said check which volume is best suited to your sub and your set up.

You dont want to have the bass overpowering the rest f your set up.

:)

I built a sub a few months ago, primarily for home cinema use. The only thing I needed to buy was the speaker driver (12" £30 from http://www.empiredirect.co.uk) I used an old 120watt amp I had lying around to power the sub, which is plugged directly into my av amp. This handles the crossover duties. The driver is housed in a mdf box, which is airtight silicone sealed and stuffed with pillow filling (aka pollyfill). I was lucky in that I also had the mdf knocking around.

I would make a sealed unit - stear clear of a ported box for now, cos these need a bit of tuning. You`ll also need to sort out the optimum size of box. You can calculate this using a little program called WinIsd - download it from here: http://www.linearteam.dk/statistics.asp?prog=winisd.

My box is a bit of a monster - about the size of a small fridge. It`s probably not the most refined unit, but it`s pretty awesome with home cinema and still does a decent job with music. It certainly does not sound crap (looks a bit crap, mind you) and exceeded my expectations. Have a look here, if you haven`t already: http://www.diysubwoofers.org

Good luck.

alfie,

You mention an old amp you had lying around, was this a hifi amp or car amp......just for ideas

An old JVC hifi amp... the low frequency stuff does soak up a bit of power, so you need something with a reasonable output. If you can pick up a hifi amp cheap or second-hand, or better still canibalise some old kit, might be cheaper than a new car amp.