Controlling 2 fronts, 2 rear and a sub channel

GibsonLP · 03-17-2005, 01:48 AM

Hi there,
I have most of the picture of how will my carpc look, the biggest missing part is the audio.

Since I will be using a used laptop with a broken monitor as my carpc - I will need to use some sort of USB sound card.

I want to have the ability to control the 4.1 speakers configuration in my car the same way I have now with my HU. So a stereo card is out of the question I guess (I thought about simply sending 2 channels to some sort of an audio splitter that will split the channels to 4.1 with crossoever for the sub and all that, but it means I won't be able to control the crossover/volume from the computer)

That leaves us with 5.1 or 7.1 USB cards.

1. Is it possible to have that control for a 4.1 speakers configuration?
2. Do you know of a card that has that many RCA outputs? (I don't like 1/8" outputs, they really not that good... I'll have this as last resort)
3. Is it possible to utilize the SPDIF output and stream raw PCM data of 4.1 channels (and of course - have a separate unit at the other end splitting all channels back to analog RCA outputs for the amps...)

I am sure one of you guys had to deal with this issue at one point or another, I would love to hear your inputs regarding this issue.

Thanks in advance!

Squid · 03-17-2005, 02:01 AM

I use an Audigy 2 NX to control 5.1 speaker setup. There is some issues with the audigy tho,
the software needs to upconvert the stereo sources (mp3 etc..) to the
5.1 speakers (I use the CMSS All channel stereo setting) and this setting doesn't always
stay set... very annoying. Also, it uses 1/8 inch jacks which you don't like.
You also don't have very good control of the sub crossover.. one slider setting and thats it.

But other than that, it works good and sounds awesome. Once I got it set right I never
messed with it again... just that stupid CMSS unclicking... prob could be fixed by a programmer and
a simple app that rechecked on boot...

kaptan · 03-18-2005, 12:00 PM

the audiocontrol three.1 takes 2 rca inputs, splits them up into 6 channels, rear front and sub and gives you fader controls for the rear and front, and you can do the balance from the source. it's an awesome unit..i have one myself

GibsonLP · 03-20-2005, 05:02 AM

Thanks for the replies guys.

I would like to find a way and control these channels on the computer itself, I'll use solutions such as audiocontrol three.1 only as a last resort as 1. it's less sleeky than doing it on the computer, 2. it needs some space which I don't really have on the dash.

I wonder if alsa is capable of having this "all stereo" functionality as the cmss has.

Thanks again.

Any more ideas anyone?

TheChiman · 03-20-2005, 11:13 AM

Hi everyone, I'm a new poster. I've been doing some research into USB soundcards since I'm planning on a Mac Mini install and there's only the 1/8" audio jack. M-Audio make the Sonica Theather and Turtle Beach makes the Audio Advantage Micro. Both output S/PDIF. The Sonica is a coax and the AAMicro is optical I believe. The Sonica also has the 1/8" jacks and is 7.1. I'm not sure exactly about the Micro. Check them out for yourself.

RedGTiVR6 · 03-20-2005, 12:53 PM

one thing you will want to keep in mind is the voltage output of these cards. Some cards only out out a volt or two. In general this isn't enough to give your signal a decent level for an amplifier. Some people swear that 2 volts sounds great, I myself, wouldn't be able to stand it.

It depends on your listening tastes and how your ear percieves music. if you are perfectly happy with lower quality sound then go for it. if you are like me, and a number of other people on here, you won't be happy with that so you will need to run something to boost your line voltage to a respectable level, especially if you are going to be running any aftermarket stereo stuff.

GibsonLP · 03-21-2005, 03:35 AM

How do I know how much voltage does the SB audigy NX or the SB live! 24 external output?

In any case - I don't think that amplifying the voltage of a 1/8" plug is a good idea - that would amplify the external interference that this low-quality connecter already has.

Best thing (If I could do it) would be to send everything out via spdif to a more professional unit that would grab the SPDIF and output 4.1 outputs (RCA, XLR, whatever

So, to sum it up, the final questions:

1. Is there a way to output a 4.1 signal from the spdif of the audigy2 NX/SB live! 24?
2. If so - is there a sound processing unit (something like the audiocontrol three.1) capable of receiving this 4.1 signal and output 4.1 separated analog outputs? (preferably via RCA)

Thanks!

RedGTiVR6 · 03-21-2005, 07:06 AM

it should be listed in the specs somewhere - usually in the detailed specifications

SPDIF would be a better option, yes. But we are still talking about the same thing...no matter if it's SPDIF, 1/8", or RCA. If you only have 1 volt of output, you really will need to boost it.

GibsonLP · 03-22-2005, 12:16 AM

I couldn't find it anywhere on their site...

In any case - I said "a more professional unit" that will output the analog outputs for me, in audiocontrol's case - they claim to provide high voltage outputs.
Thanks for the input though.

No one here knows the answer to the 2 questions I asked? that's odd...

Dave_Perth · 03-27-2005, 12:32 AM

most of the mainstream car audio brands make a processor that have optical input and then have 5.1 channel RCA output. i believe ALPINE make an audio processor which has 5Volt output on all channels. usiing a processor like that will let you use a simple soundcards with just an optical output. i think this is the best way because it means the processor which being alpine is of high quality is being feed a direct optical feed which means no possiblity of noise or interference and the digital signal is exactly what is coming off the CD the soudcard wouldnt have to do any of the sound proccessing so no chance of it doing a bad job

so it would be sorta like

S/C optical out -----> Alpine processor ----> car amp

JUST SAW THIS THING!!!!!!!

http://www.alpine.com.au/downloads/product/MRA-D550.pdf

its a processor and 5 channel amp in one WITH a 4 volt subwoofer output

GibsonLP · 03-27-2005, 12:38 AM

Hi there and thanks for the reply.

Checkout my other thread (regarding the DVH-920/940). I will probably go there

RedGTiVR6 · 03-27-2005, 09:39 AM

so you are going to go with a head unit instead of a carPC - or as well as the carPC?

GibsonLP · 03-27-2005, 11:17 AM

I am going to use the DVH-920/940 as a pre while I will connect my carpc to it using the toslink I have on the creative mp3+ USB card I just bought.
In this way the entire sound processing will be performed in the digital domain and the sound conversion to analog will be done by the high-quality Clarion unit.
This will also give me the control I want on the 4.1 speakers+sub cross cutting.
And - the Clarion offers 4v RCA outputs which should be enough.

Oh - and if you'd check the DVH-920/940 is a half-din unit, it won't be on my dash or something like that - instead - I'll install it very close to my amps and simply take a 5M optical cable from the SB output, so my analog cables are going to be short to reduce interferences even more...

I'll use the pretty small DVC-920 unit to control it.