Hey, John:

An easy way to audition two (or more) instruments together is to left-click the Solo (S) button for the first instrument you wish to hear. The Mute (M) buttons for all the other instruments will turn red and those tracks will be muted. Now, to audition a second instrument with the first, simply left-click on the Mute (M) button for that instrument to un-mute it and to hear that track play simultaneously with the first. You can add other instruments in this way, if you so desire.

I hope that's helpful.

Be well, be happy.

Sincerely (No, I really, really, REALLY mean it this time!), Bro. Dave