Date: Mon, 5 May 2025 15:33:14 -0700 From: "G. Paul Ziemba" <pz-freebsd-multimedia@ziemba.us> To: freebsd-multimedia@freebsd.org Subject: Re: 13->14 microphone routing/mixing issues Message-ID: <aBk8qrpeN5DPOvC5@hairball.ziemba.us> In-Reply-To: <kns5qtduplbukx7o27mgictbhgxqwflb7hif4dvtpke5tpycmu@teebiio54m3l> References: <aBjsoOqlo_Vw982N@hairball.ziemba.us> <kns5qtduplbukx7o27mgictbhgxqwflb7hif4dvtpke5tpycmu@teebiio54m3l>
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On Mon, May 05, 2025 at 07:02:08PM +0200, Christos Margiolis wrote: > G. Paul Ziemba wrote: > > Hi, > > > > I upgraded from 13-stable to 14-stable last week, which seems to have > > changed some aspects of the audio system. > > > > My microphone is now being played out the speaker, resulting in > > feedback if the microphone gain is above zero. I read the mixer(8) > > man page but I don't understand what is wrong. > > > > Although setting the microphone gain to zero quells the feedback, > > doing so also means there is no microphone signal toward, e.g., > > teleconference software in the web browser. > > > > How can I make the microphone usable again without feeding into the > > speaker? > > > > Speakers and microphone are attached to the "rear analog" ports. > > > > % mixer -a > > pcm0:mixer: <Realtek ALC888 (Rear Analog 5.1/2.0)> on hdaa0 (play/rec) (default) > > vol = 0.86:0.86 pbk > > pcm = 1.00:1.00 pbk > > speaker = 0.74:0.74 rec > > line = 0.01:0.01 rec > > mic = 0.00:0.00 rec src > > mix = 0.74:0.74 rec > > rec = 0.35:0.35 pbk > > igain = 0.50:0.50 pbk > > ogain = 1.00:1.00 pbk > > pcm1:mixer: <Realtek ALC888 (Front Analog)> on hdaa0 (play/rec) > > vol = 0.84:0.84 pbk > > pcm = 1.00:1.00 pbk > > speaker = 0.00:0.00 rec > > rec = 0.35:0.35 pbk > > igain = 0.00:0.00 pbk > > ogain = 1.00:1.00 pbk > > monitor = 0.67:0.67 rec src > > pcm2:mixer: <Realtek ALC888 (Rear Digital)> on hdaa0 (play) > > vol = 1.00:1.00 pbk > > pcm = 1.00:1.00 pbk > > pcm3:mixer: <Intel Kaby Lake (HDMI/DP 8ch)> on hdaa1 (play) > > vol = 1.00:1.00 pbk > > pcm = 1.00:1.00 pbk > > > > Thanks for your insights. > > After a quick search I do not see any change to ALC888 between 13 and > 14. However I see your "igain" (input monitoring gain/level) is set to > 0.50. What happens if you set it to 0? > > $ mixer igain.volume=0 Thank you, that set me on the right track. I didn't know the meaning of "igain" (apparently it is on the snd_hda(4) manpage). It looks like setting igain.mute=yes would have the same effect. I'm still experimenting with "rec" and "mic" volume levels on the microphone signal toward MS Teams in the chromium browser. It seems to me that "mic.volume" has no effect but setting "rec.volume" to 0.99 yields an acceptable level. But I haven't made enough experiments to be certain. If you are aware of a good way to observe/measure the effects of varying the mixer controls in the "record" path, I'd be glad to know. thanks! -- G. Paul Ziemba FreeBSD unix: 3:16PM up 9 days, 2:45, 17 users, load averages: 0.17, 0.31, 0.25
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