Getting soundcard levels with alsasound on Linux dialed in for any Amateur Radio soundcard based comms can be tricky (at least in my experience).
If you’ve plugged in an additional USB soundcard device like a Rigblaster or a SignaLink, it’s important to know that the ‘master’ volume level in alsamixer applies to all soudcards. Make sure you have the master volume up, in addition to the soundcard that you have going to your transceiver.
Here’s what the default soundcard alsamixer display looks like for me – notice the master volume not muted (MM = muted), and level around 3/4:
Press F6 to switch/select the USB Rigblaster device levels.
Here’s alsamixer for Rigblaster USB soundcards, playback/output (F3) at 3/4:
Capture/input (F4) at 3/4: