From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kai Vehmanen Date: Fri, 03 Sep 1999 18:08:12 +0000 Subject: ecasound as a virtual effect box :) Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sound@vger.kernel.org I tested realtime effect processing with ALSA drivers and it turned out to work rather well. I've tested this quite a lot with OSS/Linux, but never with ALSA devices. Anyway, with a buffersize of 128 samples (~3ms) and raisen priority, there were no dropouts and as there's no file-i/o, I was able to use more complex effect setups than when doing normal file playback. I guess with Ingo's kernel patches, I could use even smaller buffersizes without losing stability. But 3-6ms~ is already quite good. It's a good sign, that I could play "live" with my drum machine without noticing any processing delay... It actually turned out to be so much fun that I spent hours playing with my guitar and trying different effect setups. :) Most ecasound's effects are pretty simple, but when you combine them, things start to get interesting. Especially with delays and reverbs, you can do stuff that is impossible with rack effects... I'd love to do some ecasound testing with the new AMD Athlon (I have a 166MMX now...). With that CPU-power you could do much. Well, here's an example...: ecasound -r -c -b:128 -a:1,2 -i alsa,0,0 -o alsa,1,0 \ -a:1 -eas:50 \ -a:2 -efl:800 -etr:400,0,60 -eas:200 This adds a 400ms reverb to the low frequencies. Sounds quite dub-ish when I put my drum machine through this. ;) Works quite well on my machine, but if I try to add more chains or cpu-intensive effects (delay, filters), I quickly run out of cpu-power. -- Kai Vehmanen ----------------------------- CS, University of Turku, Finland : email mailto:kaiv@wakkanet.fi : audio processing for linux http://www.wakkanet.fi/ecasound/ : my music (ambient-idm-rock-...mp3/ra) http://www.wakkanet.fi/sculpscape/