Change? NO. Not at all. I STILL feel the PSR2000's onboard mixer is 'all that's needed' for most gig situations. Even so, there are a few larger situations where adding an external mixer will provide increased signal to 'maximize the most' out of the speakers resulting in even MORE clarity, punch, and volume. Other avantages to using an external mixer (ok yes, I still on rare occasions use my little Mackie 1202 workhorse) is that it provides additional XLR mic inputs (and EQ/balance control) for backup musicians & guest singers, outboard efx processors & external vocal harmonizers (Digitech) , a CD player, etc. The 2000 has an impressive sounding buitl in mixer & vocal efx processor & harmonizer section, but it still can't compare to vocals run thru a dedicated external vocal EFX- harmony processor with XLR mic inputs and the convenient 'on the fly' adjusting and fine tuning an external mixer provides. I hope this clarifies my position. - Scott Yee