All but the Casio Privia 160 have driums built in and pretty good speakers. The full backing functions are really simple to use if he wants more than just drums. Tell him to upgrade to a 360 or I have my Privia 350 for sale if he's interested. As for a harmonizer in a NH I can't see why you would need one.
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Bill in SC --- Roland BK9 (2) Roland BK7M, Roland PK5 Pedals, Roland FP90, Roland CM30 (2), JBL Eon Ones (2) JBL 610 Monitor, Behringer Sub, EV mics, Apple iPad (2) Behringer DJ mixer