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herrzinter

Member

Registered: 2019-12-15

Posts: 23

[SOLVED] Microphone Gain Adjustments in Pipewire / Gnome

I have a Blue Yeti Nano mic and I am currently using pipewire. Now, if I adjust the mic volume slider in gnome, do I just adjust how much the digital signal in gnome is amplified or does this actually affect the internal gain of the mic? I always thought the latter was only possible using the driver gui on windows. However, when I change the slider, the internal monitor of the mic itself changes volume, which suggests to me that this actually changes the internal gain.

Not sure if this is the right place btw, please correct me if I'm wrong.

Last edited by herrzinter (2023-04-18 15:37:36)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 23,841

Re: [SOLVED] Microphone Gain Adjustments in Pipewire / Gnome

Generally pipewire's volumes for a device adjust the actual volume of said device provided it exposes such information to the operating system (or simply the digital signal amplification if that isn't the case). So that you see this being reflected will mean that the mic does expose a HW mixer to control the internal gain. To verify that check

arecord -l #Find out the card index of the mic
amixer -c0 #Or rather the card index of the mic

if you have an exposed "Mic" control here or similar, you should see that moving when you adjust the slider in GNOME/Pipewire. For the general logistics of how this works you can read https://www.freedesktop.org/wiki/Softwa … MyVolumes/ (pipewire copied this logic and it works the same way in principle)

herrzinter

Member

Registered: 2019-12-15

Posts: 23

Re: [SOLVED] Microphone Gain Adjustments in Pipewire / Gnome

Thx! It indeed does, see output of amixer

Simple mixer control 'PCM',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 62
  Mono: Playback 62 [100%] [6.00dB] [on]
Simple mixer control 'Mic',0
  Capabilities: cvolume cvolume-joined cswitch cswitch-joined
  Capture channels: Mono
  Limits: Capture 0 - 33
  Mono: Capture 16 [48%] [16.00dB] [on]

Side note: If I selecte "Pro Audio" in pavucontrol as profile for the mic, the opposite behavior can be observed, namely, the slider does not affect the devices internal gain, which can probably act as a nice verification.

herrzinter

Member

Registered: 2019-12-15

Posts: 23

Re: [SOLVED] Microphone Gain Adjustments in Pipewire / Gnome

... however, I just checked with another microphone, which has a hardware knob to control its gain, and amixer seems to give a very similar output which is controlled by the gnome slider, but which does not correspond to the internal gain, as this is controlled by the knob. So I'm not sure, if you can really very it like this?

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 23,841

Re: [SOLVED] Microphone Gain Adjustments in Pipewire / Gnome

Yes, all of this depends on how the internal firmware of whatever you are using interprets whatever else. It could be that your secondary mic actually has a hidden gain that it only controls internally, while still providing a control to the OS. In general USB devices are black boxes and how things are implemented internally is completely up to the firmware/board vendor. The only thing it should do is expose the common bits and pieces so that an operating system considers it a valid USB audio device.

Pro Mode enforces software volume as to not adjust anything "automatically"/surprisingly because pro mode use is expected to need to be able to control everything precisely.

Last edited by V1del (2023-04-18 13:44:30)

herrzinter

Member

Registered: 2019-12-15

Posts: 23

Re: [SOLVED] Microphone Gain Adjustments in Pipewire / Gnome

Makes sense, thank you!