[sdiy] Do I really need any more projects? organ mechanics

[Bill Felton]

On Jan 2, 2005, at 12:57 PM, Andreas Gaunitz wrote:

>> Sounds like fun brewing on the electro-mechanical front.
>> A MIDI-controlled PVC pipe organ ought to be interesting.
>> Keep us posted...
>>
>> Oren
>>
>> -----Original Message-----
>> From: James Patchell <patchell at cox.net>
>>
>> http://www.oldcrows.net/~patchell/OddMusic/OddMusicalInstruments.html
>>
>> Some electro mechanical instruments I am thinking about....
>>
>>          -Jim
>
>
> One thing I've been thinking about is the size of the different pipes 
> on an organ. Why are the low note pipes thicker than the high notes'. 
> What decides the thickness?
>
>

Insofar as I recall, the width of the pipe stands in a specific 
proportion to the width of the mouth of the pipe.  The general scaling 
ratio for pipes is expressed in terms of 'halving on the nth', with 
pretty much no pipe scales halving on the octave -- usually more pipes 
before the half-width point.  I'd have to look up details, but that's 
the basics.  Width to mouth width to mouth cutup (height of opening) to 
air pressure to constriction at the pipe hole to nicks in the windway 
or 'beards' in front of the mouth seem to be the (roughly in descending 
order) determinants of the characteristic sound -- after pipe shape and 
covered/uncovered, that is.
Hope this helps.

cheers,
Bill