ETD question re: unisons

[D.Martens]

Richard wrote:
>>This begs the question, "how do the 3 ETD's
>>(RCT, SAT, and TL (TuneLab) read a unison then a single string of >>that
>>ison?   ---ric

Like I said before, they don't always give the same readings.....
I actually used different ETD's simultaneous  on multiple U1 ,U3, C3 models
, with exactly the same tuningchart being active in both ETD's at the same
time, at the same pitch. Especially in the higher octaves, different
readings occur sometimes. The fundamental is the only partial being used in
those octaves.

Duncan





-----Original Message-----
From: Richard Moody <remoody@midstatesd.net>
To: pianotech@ptg.org <pianotech@ptg.org>
Date: Monday, February 19, 2001 5:41 AM
Subject: Re: ETD question re: unisons


>
>
>----- Original Message -----
>From: Michael Jorgensen <Michael.Jorgensen@cmich.edu>
>To: <pianotech@ptg.org>
>Sent: Thursday, February 15, 2001 4:05 AM
>Subject: Re: ETD question re: unisons
>
>
>>  Many individual strings can full blush for several
>> seconds (be very close), only to suddenly register flat-- a whole cent
flat
>for
>> a brief instant and suddenly return to full blush.  Could the soundboard
be
>> forcing/imposing a frequency against the will of the string and simply
winning
>> the battle for a second or less?
>> -Mike Jorgensen
>>
>Of course the sound board is vibrating along with the string(s)  And the
bridge
>in between also.  But let us not forget that ETD's like all measuring
machines
>have limits.   At one point in our investigation we have to ask the
question,
>what are the limits, are we at the limit?.
>    Another consideration that has not been addressed is that ETD's do not
>actually measure the vibration rate of strings themselves.  They give us a
read
>out of what the microphone is picking up from sound vibrations excited by a
>soundboard excited by piano strings.  AND some are converting to digital.
It
>would be interesting to see if magnetic or ceramic pickups gave the same or
>different readings.
>    This  gets to the determiniation of the accuracy of the instrument.  If
two
>instruments (of different design) always give the same reading it is
reasonable
>to assume the readings are "true".  This begs the question, "how do the 3
ETD's
>(RCT, SAT, and TL (TuneLab) read a unison then a single string of that
>ison?   ---ric
>
>