Pipe Organ Pitch Variation

[David Porritt]

List:

In the October 1998 PTG Journal, page 21 is an article on this very subject by Jim
Ellis.

dave

Conrad Hoffsommer wrote:

> At 23:59 11/30/98 EST, you wrote:
> >
> >It is common knowledge that the pitch of a pipe organ varies with room
> >temperature, but just how much?
> >
> >Occasionally I will be asked to tune a church piano with the pipe organ when
> >the sanctuary is much cooler than it will be on performance day. I check the
> >organ and it is off pitch. The question is, is there some formula that will
> >tell me where the organ pitch will be at normal room temperature. In other
> >words, if the room will be 10 degrees warmer when the piano and organ will be
> >played together, how much will the pitch change?
> >
> >Dave Bunch
>
>  From:
>
> "The Art of Organ-Building"
> George Ashdown Audsley - 1906, Dover reprint 1965
>
> Vol II, p. 637:
> Chart-
>
> "Vibration-numbers according to diapason normal at different temperatures"
>
> 59F - 435.0
> 60  - 435.4
> 61  - 435.9
> 62  - 436.3
> 63  - 436.7
> 64  - 437.2
> 65  - 437.6
> 66  - 438.0
> 67  - 438.5
> 68  - 439.0
>
> A fancy numeric formula didn't jump out at me, but may be deduced from the
> text when my eyes open fully, but from that short list it looks almost like
> 4/9Hz per degree F.
>
> Conrad
>
> Conrad Hoffsommer       mailto:hoffsoco@luther.edu
> Luther College          (319)-387-1204
> Decorah, Iowa 52101-1045
>
> The best things in life aren't things.



--
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David M. Porritt, RPT
Meadows School of the Arts
Southern Methodist University
Dallas, Texas
mailto:dporritt@swbell.net
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