Re: Tuned metal bodies

[Tan Cheng Ann <BA2319140@xxxxxxxxxxxxxxxx>]

From: William Lippe <lippe@xxxxxxxxxxxxxxxx>

>> apart from the question of playing the harp in other positions, which
>> Tim raised...doesn't the metal body have only one 
>> natural/resonance frequency?
>	It may have its fundamental at one frequency, but all wavelengths 
>corresponding to the equation 
>	lambda=1/i or  Lambda being the wavelength, and i being all 
>integers. 1 is the original wavelength of the frequency the body is tuned 
>to.  This means that all of those frequencies (fundamentals) will vibrate  
>the entire harp (sympathetically) also. Unfortunately, I don't have to do 
>the calculation to tell that the frequencies pointed to in Winslows post or
>the Harp Handbook will not all be fundamentals of the tuned body, and hence I 
>can't believe these harps won't have odd volume shifts.  Bonking the comb 
>and hearing a pling instead of a thunk just tells me "We did what we said 
>we would do, now we just have to see what we did does."

yup..i understand about those harmonic waves you mentioned.
i was just wondering about the effect of the hand/palm dampenning any 
waves that may have been resonated off the metal cover. a bell won't 
sound if the hand is hugging tightly around it, right? perhaps just a 
plonk sound?

perhaps the cover works by air acoustics?
you know..like how some of those hi-fi speakers have hollow tubes
connected to the front or back panels, to resonate the natural
frequency (and also the harmonics) of the groove? makes the bass sound
tighter and punchy. perhaps, the shaped metal cover does the same
effect? i am just speculating anyway and i know little about acoustics.
i am equally stunned and awestruck by Winslow amazing knowledge!



-cheng ann



Tan Cheng Ann
Email: BA2319140@xxxxxxxxxxxxxxxx                        "I love Wen Huey!"
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