RCT

[Roger Jolly]

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Hi Richard,
                 The cat is now amidst the pigeons.
Since you have RCT here is a little experiment for you.
Set a temperament aurally to your complete satisfaction, then measure each
note
with RCT, note the results.
Next detune and retune with RCT alone for full blush on every string.
Next go into PAZ mode and sample every string for harmonic content, being very
careful to use the same force of blow with each note. Tabulate the results.
you
will note that any small tuning errors will coincide with variations in the
partial ladders.
Now reset the temperaments with ppp blows and then with fff blows. Repeat the
tabulation process. 
You will find less mud, more light, then scratch your head. Heck my fingers
are
full of splinters. (grin)
Roger 




At 11:03 PM 19/09/99 +0200, you wrote:
>
>
>Roger Jolly wrote:
>
>> Hi Frank,
>>                A little light or perhaps, or mud on the subject. Re
>> inharmonicity, my current passion and night mares.
>>  Lets assume a reasonable curve has been calculated of equal quality, by
>> any of the three major ET's.
>>  Point 2 we are dealing with a well scaled piano but the voicing is a
>> little uneven.
>>  For simplicities sake we will look at octave 5 upwards.
>>  In this register upwards we are tuning to the second partial aurally, as
>> with the ET.
>>  If you have a very bright note the 2nd is almost non existent and the
>> inharmonicity also increases.Aurally your brain reverts to the fundamental.
>> so in the next octave you compound the error, and so on up the
scale..........
>
>Ok guys.... (Roger...grin.. thanks for the continuing supply of mud.. )
>
>What I am not clear over is this buisness of calculated scales vs realtime
>measurements. I wrote in a post a bit back that I had done this little
experiment
>with Tune Lab. I tuned  A-3 and A-4 as a 4:2 octave and verified this with
Tune
>Lab. Then I figured my own temperement by dividing the real time frequency of
A-4
>by that of A-3, took the 12th root of that and arrived at frequencies for all
the
>inbetween notes. Since I was useing the frequencies (A-3 and A-4) of the 5th
>partial of each, and then the 4th partial of each I had two sets of equally
>spaced frequencies for the 5th and 4th partial of each note inbetween the 2
A's.
>I tuned each of the inbetween notes to the 5th partial frequencies and
checked
>them against the 4th partial frequencies (didnt have to change anything
really
on
>the check round). This gave me a really nice temperament with very evenly
spaced
>thirds.
>
>Ok... after doing that I tuned the rest of the piano using Tune Lab as I use
my
>ear. That is to say I directly referenced the partial of the note I was going
to
>use as a reference note by zeroing in on the frequency of its partial and
locking
>the setting on that, then tuned the notes corresponding partial to that
setting.
>For example take A2... I set Tune Lab to read the 3rd partial of A3, adjusted
the
>offset til the display stayed still, and locked onto this setting. Then I
tuned
>A2's 6th partial to this setting. I used standard appropriate octave types
for
>each register of the piano, but tuned the entire piano in this fashion. The
>result was an extremely evenly tuned piano. Thirds, tenths and seventeenths
>progressed very evenly indeed.
>
>What I liked about the experiment, was that I used the computer and Tune Lab
to
>make sure that what I try to do with my ear was like dead on. This took all
the
>calculation (with the exception of the temperatment itself) out of the
picture.
>What I did not like about it was that it was a bit time consuming. (took over
2
>hours to do). I figure tho that as I am new to ETD's I could improve on the
time
>after a bit, and that I could get good at adjusting for and neccessary
changes
>with regards to stretch and partial problems underways.
>
>Now I have used RCT a bit more, and what I like about it is that I get better
>speed, but I find that I am not always happy with the amount of stretch (tho
it
>is always very even), and I feel kinda like I am out on a limb trusting that
this
>"calculated tuning" is going to be good enough. Again, I figure that given
time I
>will be able to merge the RCT with what my ear wants (in general from a
tuning)
>and get a good result.
>
>My "question" is then, (given your statements about inharmonicity,
strength of
>partials, and how these change under conditions such as those voiceing can
>present) Which ones of these two methods is really the most dependable, or
shall
>I say will result in the most "correct" tuning ? (I assume here that both RCT
and
>Tune Lab are equals when it comes to measuring accuracy) If you have an
opinion
>on this, I would also like to hear (as in depth as you can get inspired
enough
to
>write.. grin) your reasoning.
>
>Thanks..
>
>Richard Brekne
>I.C.P.T.G.  N.P.T.F.
>Bergen, Norway
> 
Roger Jolly
BaldwinYamaha Piano Centre
Saskatoon and Regina
Saskatchewan, Canada.
306-665-0213
Fax 652-0505 
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