Behringer 1500 amp for subs?

[Bogie]

So, what do y'all think? Good, bad, indifferent? Target is four Dayton Quatro 15s, ported.

Will I need an external crossover/gain control feeding it the LFE signal from a Denon 2803?

[simon5]

Good idea, you'll have awesome results if built well.

You don't need an external gain control.

You might need a x-over but your Denon probably have one built-in.

[norty303]

I don't know the driver at all but am I right in thinking its 300wrms @ 4R?

How are you planning on wiring them up? I suggest 2 series pairs wired together in parallel. At 1200wrms for the 4 I think an EP2500 would be a better bet but thats coming from a PA perspective and from the driver I take it this is car audio. 2 times rms is the genrally accepted power rating for amps on subs

[Bogie]

Nope, it's for my basement...

Right now I've got a pair of 'em in 5.5 cubic foot sonotubes, but I've got two more still in the boxes... Just need ampage.

I'm thinking that 1,000 or slightly above, into a 4 ohm load, will work. The LFE signal is mono anyway...

Thought #2 would be to split the preout from the mains, in addition to the original pair dedicated to LFE. Hmmm....

[norty303]

In that case, if you really want to get the most out of them I'd recommend the EP2500 (or even better the QSC RMX2450) bridged into the 2 tubes. Wire each tube in series (making an 8R load) then wire the 2 tubes together in parallel (back to a 4R load). You'll get 2.4k into the whole thing then and really make them sing.

I've got 2 x 18" (8R) bandpass subs rated at 1200w @ 4R for the cab which I run off a bridged RMX2450 or EP2500 and they rock HARD!!

[xstephanx]

WAY to much power per sub

250 each should get you to full potential(or almost) with that driver in a box that size.

at 16 hz in a 5.5 cubic foot box tuned to 21 hz, it takes a mere 250 watts to send this thing to max linear excursion.

Since extension down to 16hz is IMO the perfect cutoff point for most HT, it models very nicley with 4 of these in said boxes getting 250 watts each.

That being said, amplifier head room is always something thats nice to have, just make sure that you dont run into excursion problems.

Also if a high pass filter was utilised at 18hzish, then you could get away with 400 watts, but i dont see a oint as tahts higher than the drivers RMS limits, and with as much headroom as you have with 4 15"s you dont need to push drivers that hard to get astounding amounts of bass.

Happy building!

[norty303]

The rms rating of a driver is based on continuous power applied which music isn't. If the box is tuned for those very low frequencies then presumably the driver will not become unloaded and suffer from overexcursion.

Have you modelled the drivers/cabs in Winisd or Bassboxpro to see where you may reach xmax or xmech?

As i said, I'm coming at this from a PA background and the application wasn't stated.

[xstephanx]

I used winisd pro to model the excursion.

And why bother overpowering it when you can just make a bigger box and use less power?

[Rademakers]

WinISD (and others for that matter) simulate with a 3dB sine wave, which music luckily isn't. So if WinISD states it will reach Xmax @250 Watts, it will actually reach Xmax at in between 250 Watt and 500 Watt with music. Heavy bass will be about 4 to 6 dB (dynamics). With 3 dB actually being the sound of a sine-wave (never heard it in music and hopefully never will)

With tops (speakers meant for only high frequencies) you could, depending on the kind of music and crossover frequency, put 2 to 3 times more power into the drivers then the mechanical powerhandling stated by WinISD Pro. Normal music will at least have 9 to 12 dB of dynamics in it.

The Pe is only the electrical powerhandling. If it's 300 Wrms, it would be able to withstand 600 Watts of music without being electrically overpowered. This will go only for for trustworthy manufacturers tho. My guess this is one of them.

In this case you could power it with up to 500 Watts of music. But as the available power from your amplifier rises the danger from clipping will be also much larger. So in cases you don't know what your doing or you have other people using your equipment be very cautious. For parties limiters are advised.

Speakers for home entertaiment or PA might be very different but the good ones will have the same theory behind them

Mvg Johan

[norty303]

In this case you could power it with up to 500 Watts of music. But as the available power from your amplifier rises the danger from clipping will be also much larger. So in cases you don't know what your doing or you have other people using your equipment be very cautious. For parties limiters are advised.

Actually the danger of clipping the amp is greater when using the smaller amplifier. In order to achieve the desired output you may well risk pushing the smaller amp into clip where the larger amp will still have headroom to spare. But you've put into words what i was trying to explain regarding rms and music power ratings.

BTW, some Drum n Bass basslines are very close to a sine and sometimes sustained. When doing PA for these sorts of gigs i often reduce the output to the subs by 3db