<HTML>In a message dated 6/2/02 10:59:33 AM Central Daylight Time, mfarrel2@tampabay.rr.com (Farrell) writes: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">I thought there were about 4 cents per cycle per second in the middle of the keyboard. So would you not need a difference of 4 cents between two strings to get 1 beat per second? That would make the PTG exam tolerance of about 1/4 beat per second, or 1 beat per four seconds. Or am I missing something? </BLOCKQUOTE> Sorry it took me so long to answer, I've been very busy lately.  The unisons are all read on Octave 5 according to the Exam manual.  This means that the notes from C3-B3 are read on their 4th partial and the notes from C4-B4 are read on their 2nd partial.  I use the same partial selection when I set up a programmed tuning in my SAT. Let me put this another way.  We do not read every string of every unison.  We first play the unisons from C3 to B4 at a tempo of about one per second.  We make a mental note of any unison which apparently stands out as having some kind of beat in it.  Then, starting over, we play through the unisons and upon each one that any member of the committee suspects may be out of tolerance, we measure.  Any difference between any  2 strings of 1 cent or more will have points deducted. Many pianos do have false beats, so when one is present, it is likely that the unison will be measured.  The same rule still applies.  What I have found from experience is that any unison with an obvious beat of 1 per second or more will have points deducted.  Those with a very slight or slow beat often are found to be within tolerance. While I still tune with making a unison as beatless as possible as the goal, there does seem to be some opinion out there about a unison with a very slow (less than 1 beat per second) having an appealing quality.  To me, however, deliberately creating a beat within the unison would tend to confuse the fine work that would have been done in perfecting temperament and octave stretch. Bill Bremmer RPT Madison, Wisconsin <A HREF="http://www.billbremmer.com/">Click here: -=w w w . b i l l b r e m m e r . c o m =-</A> </HTML>