Tomi Ollila wrote: >Hi > >I've been wondering/working a bit trying to use microphone and headphones >at the same time in different Linux systems; I have exactly the same >problem in both systems, and the "partial" fix works similarly in both >systems. > >I've tried to find out documentation of the problem, with low success >ratio; I'd be suprised is no-one else has same problems... maybe >the search keywords I've been using has been poor choises... > > Very strange this, because I started a not unrelated thread (called "using jack-rack as a real time effects processor") on this list on the 31st of January, but for some reason it is not archives. >As a last resort I turn to this list ;/ > >The problem is when opening the audio device in full duplex mode the pcm >output is feed back to the input; this continues even I mute the microphone >input -- then I just can not feed more of my voice back to the "loop". > > [big snip] My problem was similar, I was trying to use my Sound Blaster pci 128 ( ens1371 ) with jack-rack ( http://pkl.net/~node/jack-rack.html ) as a real time effects processor, and the signal from the input was being echoed straight to the output, causing horrible feedback. The solution for me, was adjusting some settings in alsamixer. Unfortunately, I have since got a new computer, which I intend to install alsa on this weekend, and my old box isn't set up, but, this was the solution for me, IIRC: I set "Line" to capture by selecting it with the curser keys and then pressing spacebar. Then i pressed 'M' to mute it. I think i had the volume down on the 'Capture' slider and had that set to 'capture' as well (by pressing spacebar). I'm not sure if this relates to you, because it looks like what you are trying to achieve is slightly different. Actually, using jack in some way might expand your options. I hope this helps in some way, regards, Jordan.
