[Harp-L] tuning and reed shapes

[Jonathan Ross <jross38@xxxxxxxxxxx>]

Michael writes:

"The main problem with chords on a standard chromatic is that the
instrument has not been voiced after being tuned."


No.  The problem is that it's in 12 tone equal temperament and thus  
there is significant beating in both major and minor chords.  I'm not  
sure what you consider "voicing" in this example but this problem  
exists in equal measure in all Equally tuned instruments.  It's more  
noticeable in instruments which can sustain chords for long periods  
(including the harmonica and accordion) and perhaps paradoxically a  
bit more noticeable in instruments where the fundamental is more  
pronounced (try playing a three note 12TET major chord using just  
sine-waves: the beating is very distinct).

Anyone who tells you that they can do something other than adjust the  
tuning to minimize or make the harshness of the 12TET chord go away  
is simply wrong.  Actually, the best way to make something which  
deliberately beats (as in 12TET, unified organs or simply unstable  
tuning) less noticeable is to make it significantly worse.  Assault  
the ear with movement.  Thus Theatre organs tend to have extreme  
tremolos (ie, vibrato), the Hammond (several beating elements  
involved) was paired with the Leslie speaker and accordions and  
others use celeste and tremolo effects (sounds deliberately beating).

Michael again:

"By cleaner I mean a
tone response that is sharp and clear in the desired note and lacking
as much as possible unwanted secondary enharmonic tones."

I would strongly advise against using such weighted language as  
"unwanted".  It implies that there is some endgame of timbre against  
which all else is measured.  Besides, what you really mean to say is  
a note with a more pronounced fundamental and weaker upper  
harmonics.  There is nothing wrong with that, but it's not "better"  
than the opposite.

For the record regarding reed-shape, there has been some discussion  
of this in the archives including some excellent posts by Rick Epping  
showing some amazing shaped reeds he's experimented with.  I have at  
least one harmonica with trapezoidal reeds (similar to many accordion  
reeds) and while it projects more than many, I can't claim that is  
solely do to the difference in reed shape.  For the most part, it  
sounds like a harmonica.  And for the most part, harmonicas sound  
like the other members of the free-reed family, which all tend to be  
very similar unless you get to very drastic differences like the  
extreme twisting (aka, "voicing") of 19th century American reed  
organs (and very much unlike anything I've seen on the few accordions  
and concertinae I've encountered) which is still basically  
recognizable as a free-reed, or the frequency specific matched  
resonators of something like the Vocalion, which can be much more  
effective at altering the timbre.





JR Ross