Lukitoh: I know of no 'midi controled' vocal harmony processors that sell new for $100. I own the Digitech Vocalist Workstation EX which sells for $479 at Zzounds.com: http://zzounds.com/love.music?p=p.DGTVOCWORK&z=1494358300867

Digitech also produces a rack module version ($329): http://zzounds.com/love.music?p=p.DGTVOCVR&z=1494358300867

You may be able to find these units 'used' on EBay for less money.

IMHO, the above vocalizers sound better than the built in one that's built in on the PSR2000, but the one in the PSR2000 sounds fine for most of my live gig situations. In fact I rarely take the stand alone Digitech Vocalizer out on gigs anymore. Dollar for dollar, I think that it's worth upgrading to the PSR2000 to gain the acceptable quality sounding built in vocalizer. Another worthwhile reason to upgrade is that the PSR2000 supports 1 megabyte of user memory storage vs only 512 kilobytes on the PSR1000. Hope my comments help you in deciding which way to go.

- Scott