Hi Again, PDG,

Depends on what book you read...
Finaly dug this one out of a box...

Fundamentals of Musical Acoustics
Arthur H. Benade
2nd, Revised Edition
Dover 1976, 1990.

A Very Respected Scientist.

Index contains several references to "Vibrato" that each definitely refer to PITCH variations. No found reference to changes in Volume only.

EB is not necessarily the best Reference.
Anybody got a Groves handy?

But I need to use 2 different terms in order to differentiate between the 2 distinct effects for my "Opus"!!!

OK, I give up! I know when I'm beat!

Now unless I get more useful references, for the purposes of my "Opus", I'm Humpty Dumpty!

DEFINE: "Vibrato: Variation in Volume"
DEFINE: "Tremolo: Variation in Pitch"

Robin :-)