Two amps to one sub???

**frugmonkey** · 09-12-2006, 12:28 PM

it might be a stupid question, but if you use a dual voice coil sub is it possible to connect two identical amps, one to each coil, and have them both set up exactly the same?

has it been done before, or is it just a silly idea?

**bes51659** · 09-12-2006, 12:40 PM

Quite possible. But even better is to combine bass from both left and right in one speaker without haveing a filter to get a center bass.

**bes51659** · 09-12-2006, 12:44 PM

With two voice coils you get all kind of possibilities.

You can connect them in parallell to get low impedance and high power output from one amp, or you can connect them in series to get 4 times that impedans and that much better damp factor. (better bass definition)

Or you can use a stereo amplifier as suggested.

**scott_fx** · 09-12-2006, 01:15 PM

in theory you could, but in application you'd probably end up ruining your sub. it's much safer to give the voice coils the exact same signal...only way you can do this is by letting them share. what happens if one component on the amp is weaker then on the other amp? you'll get a difference in the signals that are going to each voice coil and eventually kill the sub

**Shadow** · 09-12-2006, 02:08 PM

You can do this but you need a very expensive piece of equipment that makes sure the phase of the signals are completely aligned. This makes your idea cost SIGNIFICANTLY more than a more powerful amp.

**scott_fx** · 09-12-2006, 03:06 PM

curious...what is this piece of hardware?

**Rob Withey** · 09-12-2006, 04:29 PM

Why not just bridge the amps and connect voice coils in parallel or series?

**mbkowns** · 09-12-2006, 05:08 PM

Originally Posted by frugmonkey

it might be a stupid question, but if you use a dual voice coil sub is it possible to connect two identical amps, one to each coil, and have them both set up exactly the same?

has it been done before, or is it just a silly idea?

**Shadow** · 09-12-2006, 09:16 PM

Why not just bridge the amps and connect voice coils in parallel or series?

That's called strapping. Not all amps can do that.

Scott, I forget what it's called but Alma had to have one on her Bronco when she was still with Stillwater.

**bes51659** · 09-13-2006, 02:59 AM

I agree that in theory you might damage the speaker in one of two ways. If you have exactly the same signal out of phase the cone would not move at all and you would

a) get greater heat dissapation because of loss of emk. (The coil moving in the magnetic field will produce a contradirectional voltage that reduce current)
b) mechanical stress to the coil.

In real life the bass in stereo music is identical in left and right.

In real life the delay or phase is not difficult to maintain in low freq range. You do not need a very high quality amp as long as the impedance is not too low.

But my answer to your question is that I've never run a system like that for a long period of time.... Sorry :-)

But my question is the same as Rob's; Why? My guess is that you have an amp that can drive one coil but not the two in parallell and you are reluctant to connect them in series and loose some power. If so, don't buy a second identical amp. Buy a new one, adapted for the impedance of the two coils in series. That's my recommendation anyway.

In my book the only reason for dual coil is to be able to configure your speaker to get a well adapted load to your amp with 1,2 or 4 speakers.

And my 10 cents are; forget about 1ohm to get every watt out of your amp even if it is specified to deliver at that load. Every negative effect of your transmission will increase. Cables, internal impedance of your system... In short you will get a less defined bass. And even if the power is doubled you can only just notice that increase in a switch on - switch off blind test. (Thats also the reason you should never buy a dual speaker box for twice the money and twice the size) Buy a speaker with lots of dB's /W instead.