On Thu, 2014-04-03 at 21:36 -0500, CCOR58 wrote: > Have I subscribed to the wrong list? > > I originally thought this was a help type list, but it appears to be > more of a developer's forum. This list is for both kinds of discussions. > I was looking for a forum where I could get a better understanding of > the overall linux audio system; ie ALSA, Jack Audio, pulse audio and > hardware and how they all interact. > > The individual .net or .org sites for each of these separate entities > are detailed about their own projects but seem somewhat vague about how > they all tie together. > > I thought I understood them and had a box running Mint 16 ALSA JACK & > PULSE and when I set up the jack patch system and understood what was a > dedicated connection; feeding a 1004 Hz tone into the line in on the > hardware seemed to be fed everywhere and same with a mic which caused > feedback loop and loud squeal. > > From what I read once everything showed up in the jack connections > panel, jack had control and this strange feedback should not have occurred. What connections did you have in jack? If you had no connections at all, then this sounds like the alsa mixer settings were set up so that there was a direct loop in the hardware from line in to speakers. AFAIK, Jack doesn't control the alsa mixer settings at all, and certainly not those settings that can cause loops. You can hopefully fix this with alsamixer. alsamixer has three modes that can be cycled with the tab key: Playback, Capture and All. If you select the Playback mode (which is the default anyway) and you see volume/mute elements that refer to input (e.g. "Mic"), make sure those are muted, because if "Mic" playback is not muted, it means that the mic input is played to the speakers (or whatever output is enabled). -- Tanu
