Wiring a 5.1 centre channel into front left / right amp lines

**Goines** · 05-15-2005, 01:25 AM

I posted this in another thread, but thought it would be useful here instead.

I currently use an Audigy 2 NX to run my system. I want to run it in 5.1, but I have a 4 channel amp for my front / rears, and a mono sub amp for bass.

I could just use the software to lower the volume to the center channel, but that doesn't mean that the signal will be compensated for by the side speakers. So i'm wondering if we can take the centre channel and mix it with the front right / left with wires between the computer and the amps. This would allow the software to control the volume so that you could hear the difference with the sides and the front.

The only challenge I can see is that the signals could go back up the wire and mix the right & left channels.

So, is is possible, using diodes, etc, to mix the centre channel (in wires) with the left and right, without allowing a signal to mix between the right and the left?

If so, i think this would be the best solution to 5 channel audio on a 4 channel amp (which I think is the most common scenario).

Thoughts?

**antimatter** · 05-15-2005, 03:01 AM

Any proper DSP will do that. As for your sound card i don't know beacuse i don't have. Propper 5.1 with an external Digital Surround Processor like the Alpine PXA-H700 or the Panasonic CYAC300-EX will do this already. I know for a fact that the Panasonic will do this as for the alpine i just assume becasue it is a better unit but at 6-8 hundred dollars i will hold on to panasonic.

Sorry i couldn't help more.

**albysure** · 05-15-2005, 08:56 PM

you will have to run the center channel in phantom mode which actually turn the center speaker off until you get an amp for it. it still will sound ok but you will love it with the center in there

**SickVette** · 05-15-2005, 10:48 PM

You need an amp for the center to work properly.

**albysure** · 05-16-2005, 12:11 AM

he doesn't have enough channels to use everything thats why i suggested not using the center channel

**Goines** · 05-16-2005, 03:49 PM

Okay, the main reason for this is not that I want another amp or even another speaker. I don't want a center speaker (just wouldn't fit my setup, my current MBQuarts are great), but just want to ensure that I'm getting all of the channels of audio. I read a few threads of people saying they were leaving the center channels out, or just muting them, and in a lot of situations this would mean that it wouldn't redistribute the center channel. I was just curious (haven't gotten the full wiring done yet) if muting the center channel with an audigy 2nx would cause the audio to be redistributed to the side front speakers, or if some additional settings would be required?

Pending that not working, I was curious if I could use a wiring solution to the problem (distributing the audio channel, without causing other loses in fidelity).

**albysure** · 05-16-2005, 04:41 PM

im not sure if there is a setting to not use the center speaker in your sound card. but i do know in a home audio surround receiver you have an option to not use a center speaker by selecting phantom center and that redirects the sound to the l & r speakers. it sounds fine!

**Goines** · 05-22-2005, 09:27 PM

Right.

So I have the Audigy 2NX running, which sounds great, but doesn't seem to offer the exact speaker settings I want. I basically want a 4.1 system (2 fronts, 2 rears and a sub), but it has 4 or 5.1. Meaning that if I tell it I have 4 speakers so that it will correctly distribute the 5th (centre channel) to the two fronts, I will lose my base channel. So i think i'm forced to take the centre line out and split it (in wiring) to the front left and right line-in's on my 4 channel amp.

This is where I thought I should use some diodes. When I connect the wires it will cause my front left and right channels to merge, which I don't want. So i'll need to ensure that the signal for the centre channels flows into the left and right, but does not allow any of their signals to head back up.

So unless someone else has an audigy and knows the correct way to get 4.1 out of it, would someone know (from an electrical standpoint) how I should wire the centre channel line outta the computer in this case?

**SickVette** · 05-22-2005, 10:31 PM

You can not wire a center channel for 5.1 using your left and right speakers....essentially that is called mixed mono. Two speakers running in stereo and one in mono. It is mostly used when a two channel amp is needed to run a set of seperates and a sub. Either way 5.1 will not work the way you are talking. The processor will not send some of the center info down the left speaker and some down the right speaker....it sends left info to the left, right info to the right, and center to the center. So you will need to find a way to set the card the way you want to if you want the best sound you can get from your current components or add another amp to run the center channel.

**Goines** · 05-22-2005, 11:23 PM

I'm lost. You're saying that if i send the centre signals to both speakers, as well as their respective, independent, signals I can't get the desired affect?

I guess I'm missing something, but isn't this exactly what most software does when it downmixes 5 channels to 4? Wouldn't this be the same thing, as long as the independent left and right signals are not allowed to mix (which is what software downmixing ensures)?

I mean all of this would be done prior to the amplifier, so it would seem that whether done using wiring or using software the same result would be had.

Anyway, I'm probably missing something, but I don't see why this wouldn't work.