<HTML>In a message dated 10/1/01 8:14:27 AM Central Daylight Time, tito@PhilBondi.com (Phil Bondi) writes: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">> <|it's the G#3-C4 third..that tends to be fast if I have a 'mistake' > somewhere | > > Not to  nit pick but there should be an agreed on format for naming > intervals. ..yes..I actually thought about that one for a moment before I wrote it..I am use to naming the black keys in flats, not sharps. But since working with and learning piano technology, it is more common to call the black keys in sharps..nit pick all you want with the others</BLOCKQUOTE>. We all know that the black and white keys are *enharmonic*.  That is, they represent both a sharp and a flat.  However, Ab-C is a 3rd and G#-C is the uncommonly thought of *diminished* 4th.  The way to avoid confusion when writing about intervals is to simply list them both. For example, the note G#3 may have been tuned from C#4 to create a 4th.  It now also creates a 3rd from C4.  One may want to test contiguous 3rds at this point.  Here is how I would suggest writing the instructions in such an instance: Tune G#3 from C#4, a widened tempered 4th.  Now test the contiguous 3rds Ab3(G#3)-C4 and C4-E4. Bill Bremmer RPT Madison, Wisconsin</HTML>