Don't know why I never noticed this before, or what circumstances may have created it, but play~ is being noisy. I am running Max5.0.7 on a 2.16 GHz Powerbook, OS 10.4.11. I also tried this with Max/MSP 4.6.3 with the same result.

play~ has high-frequency artifacts (just like modulating a sample with noise) that groove~ doesn't.

I need a harp sound for an upcoming piece, don't have any money, and own Finale 2008 with the Garritan Orchestra. I made a "score" in Finale of ascending half steps and exported as .aif (16-bit Integer (Big Endian), Stereo, 44.100 kHz, 62.1MB). Loaded this into a buffer~ in Max so I can access individual samples by playing back sections of this 6-minute file.

In the higher registers with play~ playback I get nasty noise, but it sounds fine played with groove~.

The short story:
play~ has high-frequency artifacts (just like modulating a sample with noise) that groove~ doesn't.

The long story:
I need a harp sound for an upcoming piece, don't have any money, and own Finale 2008 with the Garritan Orchestra. I made a "score" in Finale of ascending half steps and exported as .aif (16-bit Integer (Big Endian), Stereo, 44.100 kHz, 62.1MB). Loaded this into a buffer~ in Max so I can access individual samples by playing back sections of this 6-minute file.
In the higher registers with play~ playback I get nasty noise, but it sounds fine played with groove~.

play-noisy

play~ requires a sample point in ms, the precision of which starts to go down when the number becomes too big (search for floating point precision). The object is just not a good candidate for long sound files.

I never would have guessed the answer was so complicated.

aha! another little pesky "why?" solved by this 'ere forum. thanks.

If you really want to/need to use play~ on long sound files, check out JKC's excellent Hi Res objects, available here:

https://cycling74.com/twiki/bin/view/Share/JoshuaKitClayton

All the hi-res objects pass two 32bit floating point numbers or signals around, and interpret them as a 64bit number.

play~ noisy