interesting inharmonicity information

Richard Brekne Richard.Brekne@grieg.uib.no
Tue, 17 Sep 2002 14:13:43 +0200


Kent Swafford wrote:

> Irregularity of the lower partials, particularly in the low treble and
> bass is a known phenomenon, and is not limited to verticals. I suspect
> that it would be fair to say that all pianos exhibit this irregularity,
> even if the irregularity gets small in finer pianos.

Seems to me more and more that its pretty significant in almost any
instrument, tho the general tendency you state above is clear enough. I'm
noticing this more and more as I experiement with using the 3:1 relationship
as an tuning priority. I also observe that it seems easier to get really
smooth beat rate curves this way, which I have had a hard time with in the
bass useing other approaches.

> This phenomenon is why there is such an argument between SAT and RCT
> users about using the 3rd or 4th partial to tune in this area. If you
> use the 4th partial, there is less chance of irregularity; but if you
> use the 3rd partial all unexpected levels of inharmonicity are
> automatically compromised between the 4:2 and 2:1 relationships when
> tuning the octave.

This is interesting Kent, and it seems to fit very well with this approach I
have been fooling with of late. I use the 3rd partial to tune as far down as
I can get Tunelab to read it. In addition I am comparing the 3:1 12th and
this seems to also help to automatically comprimise the octave
relationships.

Seems to me that the irregularity is there because its a part of that
particular piano, so trying to tune it out is going to result in a smooth
curve of some partial, but perhaps not so smooth a progression of beating
rates for relavant intervals... which in the end is what we are after... or
what ?


> (Of course, the Verituner contributes its own unique
> method for tuning the tenor.)

care to extrapolate a bit :) ?

>
>
> Kent Swafford
>



--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html



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