6-channel amp for 7.1?

**pokki** · 01-21-2008, 08:26 PM

but I don't think it matters if full range goes to the sub. It won't hurt anything, right?

It will sound a bit *** though.

Sure it won't be used 99.5% of the time, but it's the .5% that matters.

Consideering your install (last 2 channels being used with a flip down screen), playing a 7.1 source through such an install will sound worse than a proper 5.1 setup.

My center channel is a powered Logitech mm28 flat NXT panel speaker...driven out of the Auzen Xplode, there is PLENTY of power for center channel use...why is that strange? What powers your desktop speakers?

My desktop speaker have a built in amplifier and plug into the mains socket.

Also, the sub runs from the center channel output from the soundcard, which is typical.

It shouldn't. The center/sub output is a stero out, not mono. One side (left) will be for sub, the other (right) will be for the center channel - may have this around the wrong way.

If it was me, and I wanted a setup similar to yours (surround sound in car + tailget system), I would set it up like so - presumign a limited budget.

5 channel amp for front, centre, rear. With the tailgate speakers wired in parallel to the front speaker with a switch over their speaker wires.

Match all the speaker to the same make/models - i.e. all boston pro's - vary the woofer size depending on install location, but that's all.

Then a mono amp to drive the sub.

So for in car listening set you PC to play in 5.1 mode. For tailgate listening set it to 2.1 and flick the switch to kill the fronts and activate the tailgate speakers (you could have this computer controlled but i'd keep it simple for now).

**krnpimpsta** · 01-21-2008, 08:26 PM

[QUOTE=WuNgUn;1168025]

Originally Posted by krnpimpsta

.

Then again, I think most 5 channel amps are for 4 channel + sub, in which case you would just get a cheap mono amp for your center channel.

QUOTE]

Center channel and sub channel are not discreet...they run off the same channel, unless, perhaps it's 5.1 DTS...

What do you mean center and sub are not discrete? Then what you are talking about is 4.0 sound, not 7.1. The .1 means the sub is discrete.

The 7.1 standard defines 8 discrete channels. Two fronts, Two Sides, Two rears, a Center and a Low freq (sub).

I think what you are talking about is creating just a regular 4 channel setup but having 7 speakers? That is not 7.1. That is just 4.0 with more speakers. For example, my car has 8 speakers, stock. Two door woofers, 4 component front speakers, and two rear deck speakers. This is still 4.0. There are only four discrete channels.

**WuNgUn** · 01-21-2008, 08:27 PM

Originally Posted by Felix509

The Sub Out or the .1 in the 5.1 or 7.1, is also known as the LFE(Low Frequency Effects) Channel.

It is completely seperate from the center channel and is digitally crossed over somewhere under 100Hz.(my home receiver has 3-4 frequencies to choose from)

Again, your talking about digital out...I'm running 7.1 analogue out, and the center/sub channels are shared...not discreet. Call it 7 channel if you wish.
The only difference is the LFE channel thru analogue out...

To get true 7.1 (8 discreet channels) you need to run the digital signal out of the sound card thru coax or fiber optical into a digital decoder
that's able to handle Dobly Digital Surround-EX, Dolby ProLogicII-IIx and DTS-EX signals...for which my sound card is capable of producing...
My amps woudn't know what to do with that noise!! Hence the analogue out, combined center/sub channel...

**krnpimpsta** · 01-21-2008, 08:33 PM

Originally Posted by WuNgUn

Read a little closer...I said it's a Logitech mm28, and it's powered...
And it's capable of holding it's own in the car!

Ok, I see that it is powered. I just checked it out: http://www.amazon.com/Logitech-97017.../dp/B000AM6QH4

I also noticed this:
Batteries: 4 AA batteries required.

If you got a 6 volt power source, I think that would work. But I think a much cleaner solution would be to leave all the amplifying to standalone amplifiers (not built-in-speaker-amplifiers).

How's this?

5 channel amp to power your 5 regular channels,
2 channel amp to power your rear tailgating speakers
mono amp to power your sub (I'm guessing you'll want alot of bass for people outside the car to be able to hear it)

Then you can run your 5.1 output from your soundcard to your 5 channel amp and mono amp. Hopefully the 5 channel amp will have a pass-through output where you can grab the front two channels and output it to your 2 channel amp - the reason I say do this instead of splitting the front channels before the amps, is because splitting will reduce the volume in only the front speakers..

**pokki** · 01-21-2008, 08:34 PM

Again, your talking about digital out...I'm running 7.1 analogue out, and the center/sub channels are shared...

No they;re not - see my post above.

**krnpimpsta** · 01-21-2008, 08:35 PM

Originally Posted by WuNgUn

Again, your talking about digital out...I'm running 7.1 analogue out, and the center/sub channels are shared...

How many connections do you have coming out of your computer?

I have 5.1 ANALOG out, and that is 3 stereo connections. One is front L/R, one is Rear L/R, and one is Center on one "side" and Subwoofer on one "side."

My motherboard has 7.1 ANALOG out. It has 4 stereo connections. The first three are the same, but the 4th connector is for side L/R.

So can you describe what your soundcard output looks like so we can better help you?

**WuNgUn** · 01-21-2008, 08:41 PM

Originally Posted by pokki

No they;re not - see my post above.

I haven't seen any documentation on the left=sub, right=center, or vice versa with the Auzentech...
If this is true, then it will be a truely discreet 7.1 setup

Even better!

For tailgate setup, I like your idea...that's basically how I was thinking about setting it up...have it switch over to the front channel, then change the sound properties to just 2 channle (or 2.1)...
Or even 2 channel, but run it thru all the speakers...

**WuNgUn** · 01-21-2008, 08:43 PM

Originally Posted by krnpimpsta

How many connections do you have coming out of your computer?

I have 5.1 ANALOG out, and that is 3 stereo connections. One is front L/R, one is Rear L/R, and one is Center on one "side" and Subwoofer on one "side."

My motherboard has 7.1 ANALOG out. It has 4 stereo connections. The first three are the same, but the 4th connector is for side L/R.

So can you describe what your soundcard output looks like so we can better help you?

Here are ALL the jacks...

Line in
Mic in
Front
Side Surround
Back Surround
Center/Subwoofer
Coaxial (SPDIF)
Optical (SPDIF)

**WuNgUn** · 01-21-2008, 08:49 PM

Originally Posted by krnpimpsta

Ok, I see that it is powered. I just checked it out: http://www.amazon.com/Logitech-97017.../dp/B000AM6QH4

I also noticed this:
Batteries: 4 AA batteries required.

If you got a 6 volt power source, I think that would work. But I think a much cleaner solution would be to leave all the amplifying to standalone amplifiers (not built-in-speaker-amplifiers).

I've already made a 5v voltage regulator for it...
I'm kinda limited on what I can use (and what will fit) for a center channel...and like metioned earlier, it'll probably only be used .5% of the time anyways...

**WuNgUn** · 01-21-2008, 08:52 PM

Okay, I see it the manual that there is an option for switching bass/center channels...
That must mean it uses stereo out for mono center/sub channels...
Thanks for bringing it up. It isn't mentioned anywhere in the manual!