Digital Xover

jkeny · « **on:** 6 Feb 2005, 09:50 am »

Is there a Xover program that outputs 4 channels (2 X tweeters, 2 X
woofers for two way speakers) digitally from soundcard (- spdif?)?

I was thinking along the lines of a program to do digital Xover (for a
two way speaker) in PC - output digital signal for the 4 channels
(along the lines of 5.1 channels from DVD audio) into a receiver like
panasonic SA-XR* and connect left tweeter to say left surrond speaker
output, right tweeter to right surrond, L woofer to Left front, R
woofer to R front.

Is this feasible in any scenario?

John

EchiDna · « **Reply #1 on:** 6 Feb 2005, 01:04 pm »

yup there is a few... the easiest and best (well it's free!) is asioxo -> now updated to ACXO... you can find it here:
http://pcazeles.perso.cegetel.net/acxo.htm

or then again maybe not... hmm on second reading you want it to be fully digital .. hmm.. oh well, it's a start

there is other programs like Brute running in linux that are supposedly better in terms of sound produced, but it certainly helps to be fluent in linux to go down that path...

GL!

jkeny · « **Reply #2 on:** 6 Feb 2005, 04:56 pm »

Thanks for the reply, EchiDna

I know about BruteFir & ASioxo but I don't believe that these will output multichannel audio on spdif or digitally (4 channels for 2 twweters & 2 woofers). I believe these out put multichannel over analog outs of soundcard.

Is there any software which will do this which maybe can be plugged into BruteFir ?

John

dwk · « **Reply #3 on:** 6 Feb 2005, 05:36 pm »

What you are asking about really has nothing at all to do with the software used, but everything to do with the soundcard.

SPDIF is inherently a 2-channel medium for PCM data. There is simply no way to get more than 2 channels of uncompressed PCM data through an spdif link, regardless of what program is doing it.

The '5.1' features on DVD etc are accomplished via lossy compression into either AC3 or DTS. The NVidia Soundstorm chips are supposed to be capable of 'realtime' encoding of 5 channels into an AC3 stream, but this is a bad idea - compressed 5.1 is noticably inferior to the original in the best of cases, and the realtime encoder is even worse than that.

The only worthwhile way to go 'all digital' would be to get a soundcard with multiple spdif output, and then use one of the approaches already out there. Unfortunately, these aren't cheap. The Lynx AES-16 offers either 4 or 8 stereo outputs (although you'd need an AES->spdif xformer for each) and runs ~700 or so I think. The Emu 1820 has 2 spdif outputs plus a bunch of analog outs, and runs $400 I think.
The Emu has no linux support, but 4Front has beta drivers available for the AES-16.

jkeny · « **Reply #4 on:** 7 Feb 2005, 01:03 am »

Thank you DWK - so I would need a soundcard with at least 2 spdif outs - would BruteFir nbe able to route the highs to one spdif out and lows to another?

John

dwk · « **Reply #5 on:** 12 Feb 2005, 08:58 pm »

I missed the activity on this thread - sorry for the delay.

John,
Brutefir can do almost anything you want, but you have to generate the filters for it. This is the biggest factor holding up wider use of BruteFir. Another big problem is that the Lynx AES-16 is the only card I know of that has multiple digital outputs that is supported at all under Linux, and that is via the commercial OSS drivers.

If you're adventurous and have a lot of $$$$, you can look at Mac OSX. Although I haven't heard any first-hand reports, BruteFir "should" work OK on OSX through Jack, so any card with CoreAudio driver would work. This gives you a wider selection of cards, but it'll be expensive.