Alesis MultiMix12USB Supplementary Manual page 3

4. Click the Audio tab.
5. Under Sound Playback, select anything OTHER than "USB Audio
CODEC." The "USB Audio CODEC" is your Multimix Mixer and you don't
want to have your regular Windows sounds (i.e., the Windows BING! and
other sounds from messaging, email, and other programs) being routed to
the Multimix. By selecting anything other than "USB Audio CODEC,"
you're having Windows route all non pro-audio sounds elsewhere and
freeing up your Multimix for recording purposes only. Doing this will
increase stability and potentially improve sound quality.