i bought fionna apple's new cd fri.it was the same way.i took it back before i opened it because it stated that the 2-ch side did not conform to cd specifications.i got the regular 'ole 2-ch disc instead.i was worried it wouldn't play in the CAL.that transport is the greatest,though a bit finicky.

and i was basically talking about stereo subs as gonk stated,but you lose flexibility(can't control the bass from the couch)