How to fix: Microphone recording levels are too quiet (or get lowered automatically)

If others on a call (Skype, SIP, ...) can not hear you loud enough, your volume levels are probably too low. Also, Skype may be changing your mixer levels.

Set a proper recording volume

1. Open your mixer software (run pavucontrol).
2. Switch to input devices.
3. If you have more than one recording device, find the correct one.
4. Make a test call to a colleague that can tell you if it's too loud or too quiet.
5. Drag the volume slider for your input device to an adequate level -- for me, 75% (-7.46dB) work fine. 100% is usually way too loud.

Prevent Skype from changing your mixer settings

Switching your microphone on and off using the hardware switch on your headset's cable will cause a clicking sound, which is too loud for Skype's taste (while it actually is not that bad) -- Skype tries to compensate for that by reducing your recording volume, which causes your voice to be recorded too silent.

1. Open Skype's settings dialog (Ctrl + O).
2. Go to "Audio devices".
3. Make sure "Allow Skype to automatically adjust my mixer levels" is not checked.