Hi Sergei Steshenko! On 2007.11.21 at 23:24:35 +0200, Sergei Steshenko wrote next: > > > Regarding soundcard and syncrhonization - M-Audio Revolution 7.1, and > > quite possibly M-Audio Revolution allow you to use external clock > > source. > > > > I meant "M-Audio Revolution 7.1, and quite possibly M-Audio Revolution 5.1 > allow you to use external clock source. In theory, yes. In practice, I wasn't able to make my M-Audio Audiophile USB get clock from external source. Well it kinda works, but at some point distortions appear, and one must force clock resync or something like that by turning card off and on. I wanted to create setup similar to this, and one of the things I learned that in order to reduce jitter, you'd want to have power as clean as possible. On-board soundchips produce lowest quality signal, pci/pcie boards have much better filtering and produce better signal, but if you want something better, you have to use card which isn't powered by PSU of your PC, and doesn't suffer from problems of its signal. So if you want best digital audio, you probably should look among external cards (usb/firewire) which aren't bus powered, and use external AC adapter. Interface doesn't matter as long as card doesn't get power from it, so choose most compatible card. I picked Audiophile USB, which supports up to 24bit/96khz (though most likely you'll use it in 24bit/48khz mode). It also supports almost any sound rate without resampling, i.e. you can drive your DAC at 44100 in bit-exact mode and get highest quality possible signal, and resampling would happen only in DAC or won't happen at all (internal upsampling mode is recommended for most modern DACs though). As about quality, all I can say is that digital output from this card sounds much better than digital output from Audigy 2 ZS (both in regular or through p16v path, presumable working in bit-exact mode in the last case). As about external clock.. Audiophile usb _supports_ syncing from spdif in, but when I tried to connecting spdif out of my DAC to spdif in on card and enabled that spdif in order to synchronize, I got just noise (or very distored signal) from spdif out on card. I could get it working when spdif out on dac was set to "no signal" or signal from some of the unsed inputs, at some conditions I was even able to get it working with spdif out set to output signal from spdif in to which sound card was connected, but this configuration wasn't very stable and after a few hours of usage the distortions could start again. Switching the source of spdif out when it was used as clock source for the card also could produce some very strange results. Due to strangeness of this recursive scheme (imagine signal path: card output -> dac input -> dac output -> card input -> clocks from CARD's original output are used to drive "next" card output?) and me not understanding how and at what point re-clockings occur, but most important: completely failing to hear any advantages of this setup comparing to simplest path, I stopped experimenting with it. Now I just enjoy music and I'm quite satisfied with it ;) -- Vladimir ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
