I had the same problem. Muting the microphone (&other input sound devices) did stop my PC hissing.
The problem is that KMix options are quite confusing for me: what does Microphone and Microphone amplifier have in common with sound output?
I had the same problem.
Muting the microphone (&other input sound devices) did stop my PC hissing.
The problem is that KMix options are quite confusing for me:
what does Microphone and Microphone amplifier have in common with sound output?