Amp advice for sub drivers?

[sploo]

[This may be better in the Amplifiers section, but it is specifically about sub drivers, so I'm hoping to find the bass freaks here]

I have a set of four Peerless XLS10 P830452 drivers (4Ohm version) that I've had kicking round for a few years. A pair of them have been sitting in a ~40 litre (1.4 cubic ft) box, wired in series to create an 8Ohm load and powered by an Alesis RA500 amp (in bridged mode). The RA500 has been fed with the SUB output from my AV receiver.

The RA500 is rated at 500w RMS into 8Ohm when bridged, and I've been more than happy with the output. Not earth shattering, but a nice bit of extra bass for movies.

I've been given approval from she-who-must-be-obeyed to build some new enclosures to make use of the extra drivers. My plan would be to make two boxes, each with two drivers, and place them near the front speakers (I can't fit another configuration in the room, so can't do four single driver subs).

The obvious solution was to get another Alesis RA500, but they're discontinued. I've looked at the Behringer A500 but it's mismatched in 'only' giving 375w RMS into 8Ohm when bridged.

I could make use of the RA500 elsewhere, so is there a better solution? Perhaps a single amp that would provide 2x500w into 8Ohm loads, or even pair of decent sub plate amps?

I've spotted the Behringer EUROPOWER EPQ1200, which claims 2x320w into 8Ohm, the EUROPOWER EPQ2000 claims 2x600w. Any other/better suggestions?

[revboden]

You could just wire up the new boxes series-parallel to keep the overall load at 8ohm, with the extra sensitivity you should get ~6db more output.

How big will the new boxes be? I'm assuming sealed.

[sploo]

Originally Posted by revboden

You could just wire up the new boxes series-parallel to keep the overall load at 8ohm, with the extra sensitivity you should get ~6db more output.

This is where my electrical knowledge falls down... surely that would be generating extra output from nothing? I.e. I can't change the wiring to get more output - only to create a load with a safe resistance level for the amp?

Actually... can you even get an 8Ohm load with four 4Ohm drivers anyway?

4+4 in series = 8Ohm
4+4 in parallel = 2Ohm

Take two of the the 4+4 in series (8Ohm) and wire them in parallel -> 4Ohm.
Take two of the the 4+4 in parallel (2Ohm) and wire them in series -> 4Ohm.

Originally Posted by revboden

How big will the new boxes be? I'm assuming sealed.

Probably around the 40 litre mark, and yes, sealed. I did look at various ported/vented options, but the size increases greatly (XLS10 isn't well suited to ports) and I'd need some filtering at the low end to prevent driver damage.

Ideally, the best configuration of the XLS10 seems to be with its sister unit, the XLS10P passive radiator. Even Peerless' own docs explore sealed/ported/passive rad and advise passive radiator.

All the more dumb that the radiator is no longer available, but you can still buy the driver!

[revboden]

Sorry, I saw the 8ohm bit at the top and misspoke. You are correct, series-parallel would give you 4Ohms.

[mdocod]

How about a Crown XLS 1500 or 2000 Drivecore series? They can do 2Ohm/channel or 4Ohm bridged so, matches your loads well, and 2100W for the XLS2000 would probably be pretty good... Might be a good idea to do some research though and see if these ratings are realistic

Eric

[pheonix358]

Parallel the new set with the originals and you will get a 4 Ohm load. If your amp can handle that it should deliver more current = more power. You will get a 6dB increase, +3 for doubling the cone area and +3 for halving the impedance. (This assumes your amp can run into 4 Ohms)

[pinkmouse]

Call it bias if you'd like, but coming from the pro audio world, I wouldn't touch a Behringer power amp with a bargepole.

Have a look at the Yamaha PS range. Good price, sound and stunningly reliable, (but Yamaha do have great after sales service if you need it, I'm not sure the same can be said for Behringer ).

[ODougbo]

You really only need 2 XLS10 drivers, I will be glad to take the extra pair off your hands.

Here's a thought, how far away are the amp(s) going to be from the subs? I ran 3meters once, with super thick wire and the box just "knocked". The advantage with a plate is the amp is right next to the driver, so no wire loss problems. That said I don't use them (plate amps), but keep the power amp(s) close to the subs as possible.

Parts Express has several "levels" of PRs to look at; I'm sure PE would help you find a match, if you go back to that idea.

It is always good to hear about a sensible woman!

[chris661]

ODougbo, I'm not sure if you're aware of the heavy import costs for us here in the UK, but the charges would almost certainly rule out the PRs.

sploo, I've been using a Samson servo amplifier for my subwoofers - one of their higher power ones ought to do nicely. They appear on eBay quite often, and have found they're suitably specc'd for Pro audio use: paralleled 15A output devices, lots of heatsinking (even the rectifier is bolted to a chunk of aluminium), and a decent power supply.
I use one rated for 120w/ch at 4ohms (though it has enough voltage swing to do 300w per side - don't think the PSU would be happy though), and have never had trouble filling large rooms with my inefficient subwoofers.

Chris

[revboden]

Originally Posted by pinkmouse

Call it bias if you'd like, but coming from the pro audio world, I wouldn't touch a Behringer power amp with a bargepole.

Have a look at the Yamaha PS range. Good price, sound and stunningly reliable, (but Yamaha do have great after sales service if you need it, I'm not sure the same can be said for Behringer ).

+1

The Yamaha P3500S would do nicely.