Vacuum as a pitch standard - not

[John Fortiner]

You experienced a 25c rise because of all those copper coins you vacuumed
off the floor. 
;-)

John Fortiner
Billings, MT 

-----Original Message-----
From: Conrad Hoffsommer [mailto:hoffsoco@luther.edu] 
Sent: Wednesday, March 01, 2006 7:32 PM
To: tune4u@earthlink.net; Pianotech List
Subject: Re: beginner seeking advice

At 18:08 3/1/2006, you wrote:
>My reference to the telephone was partly a joke
>-- althought it is an emergency source -- but, please, for the love of 
>all that's holy, don't tune the piano to your vacuum cleaner ...
>
>Unless you want a tuning that really sucks .... snicker, giggle, snort.
>
>Alan Barnard
>Salem, Missouri


The main problem with using vacuums for pitch sources is that the bags get
full. (if they have them, and they are being used properly)

As the dust fills the bag/clogs the filter, the fan pulling the air through
cannot move as much air. Since the fan is not drawing as much air, it is not
doing as much work and the motor (with less load) will run faster.

Motor runs faster, pitch goes up.

I've observed a 25¢ pitch rise in one hour on one vacuum. This does not even
take into consideration any voltage transient which may have taken place. (I
didn't have my multimeter out that day...)

;-}



Conrad Hoffsommer
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