[LAU] debugging hiss

[Rustom Mody]

Of late I am getting some amount of hiss from my speakers.
I believe its a software problem because it is absent at startup and
audibly starts sometime during the boot process.

My system is fairly vanilla h/w -- ordinary Intel desktop with builtin
soundcard, ordinary speakers.

The only non-vanilla things maybe some things I installed when playing
around with a TASCAM

Any suggestions where/how to look?