I did find alsaconf in the KDE menu -
It's a shell script and it will be most likely not in the K
menu.
Open a terminal window, type su...
Debian/Apps/System/Admin/Alsaconf
but it wants me to log in as root (not as sudo su) and I
don't recall the password I set...arrg!
...and enter the root passphrase, then type /sbin/alsaconf.
OTOH, Paul Davis threw in that it's not an ALSA problem but a
JACK one. Try setting the parameters on the command line or
in qjackctl as he recommended instead of running alsaconf.
BTW: Never forget the root password! But before you reinstall:
there are ways to reset the root passphrase...
Best regards
ce