Yes. Most MIDI piano samples are the stretch tuning.

Easy enough to detect Stretch Tuning:

Using one finger from each hand, strike the C below middle C at the same time as the C above middle C and listen to the sustained notes.

Only important thing here is to strike both notes at about the same loudness.

If you hear the little tiny "buzzing" sound of the beats, which are the exact same thing that you would hear when tuning one guitar string to another and the string you are tuning is close, but not quite dead on the other string's frequency, you get a modulation effect. The energy will not be constant.

This can also be seen on fast VU meters as well, like LED meters or the meters on computer screens. Set for Peak and not Average, of course. Look for a pulsing at the top of the meter's indication and that is the Beat.

Without the beat present, a piano or rhodes tuned dead on to Perfect Octaves, the note will simply sustain at a flat level, no tiny little joyous ear candy in the buzz, just sounds like a Xylophonem Glock or set of Vibes does when playing the same two notes simultaneously. Careful with Vibes patches, though, if you don't have one that is "motor off" then the pulsating sound of the motor spinning the reso tube dampers can mask all of this.

The Grand Piano typically has a different amount of stretch applied than the smaller pianos. Upright has its own Stretch tuning table as does the lowly short Schpinette. Due to string lengths.


--Mac