Someone try this setting on their PSR's and see if it works for them... Not sure how it will sound on the 2000/1000..... Here's the setting for the mellow grand sound I edited...

Voice R1: Grand Piano
-volume:100
-octave:0
-pan:0
-reverb:16
-chorus:0
-dsp: (DSP has fixed setting due to effect used)

Voice R2: Bright Piano KSP(XG)
-volume:72
-octave:0
-pan:0
-reverb:72
-chorus:0
-dsp (DSP has fixed setting due to effect used)

DSP Effect: 3BandEQ

The DSP effect is what plays the role here in the sound. This may sound different to everyone else. Keep in mind I used external monitors, however it still sounds good on the internal speakers... It may have a better (muffled) mellow effect on the PSR-640/740 due to the speakers having a little more bottom to them... I suggest using an external set of speakers.... Place them on their back sides setting lower and flatter than the internal speakers...... It worked well with the 550 because the body is pretty high and my Roland monitors fit nicely setting behind the keyboard...