I am a good friend and a prior customer of Charlie Hubert of "Hubert
Tuning and Repair" in New Britain, Connecticut.  He was the one who
re-veneered and restrung my piano when I lived in CT.  He attended the
Hartford Chapter of the Piano Technicians Guild Meeting last month
where Douglas Henderson was making an "ear witness" presentation.
Here's Charlie's comments:

> My father and I did attend Mr. Henderson's technical in Hartford
> concerning the "ear witness" test.  It was very interesting and he
> made many convincing demonstrations.  Doug is quite a guy and has
> really devoted his life to the player piano.  My father and I have
> installed a number of Piano Disc units and have found many of the CDs
> "wanting".  We never really knew why some songs played beautifully
> and others missed notes, with poor rhythm, etc.

Karl Ellison
Ashland, Massachusetts