String noises revisited

[Allen Wright]

yes, Hamburg B, and same agraffe.

Allen
On Jul 17, 2008, at 2:20 AM, David Ilvedson wrote:

> Hi Allen,
>
> Is this a Hamburg B?   Were you able to get the exact agraffe to  
> match the original?
>
> David Ilvedson, RPT
> Pacifica, CA 94044
> Original message
> From: "Allen Wright"
> To: "Ed Sutton"  , "Pianotech List"
> Received: 7/16/2008 12:49:54 PM
> Subject: Re: String noises revisited
>
> I replaced two agraffes on the most noticeable offenders today, and  
> both notes were greatly improved; perhaps 60 - 70% less high  
> whistle. The first one I replaced was on F#3, the note the customer  
> was most annoyed by. That note was then so much quieter that the F  
> next to it jumped out as being the worst, so I thought I'd better  
> try it on that one as well. Obviously this could go on forever, and  
> be quite time-consuming - so I've stopped it at that.
>
>
> I do seem to notice some slight abrasions (in one of the holes  
> especially) of the agraffes. The best guess I can make is that this  
> noise, which is so common in that section of B's and D's, may be  
> some kind of inherent scaling "characteristic" (tactful, no?) which  
> is exacerbated by any imperfection in the corresponding agraffe.  
> It's just not logical that this can only be related to agraffe  
> problems; it wouldn't just be in that section.
>
> Like so many things dealing with piano tone, I haven't found a  
> black-and-white solution. But at least it's greatly improved - so  
> that all the notes in that section have the same amount of this  
> noise - and the customer knows I've gone the whole nine yards.
>
> Allen Wright
>
>
>
> On Jul 13, 2008, at 3:32 AM, Ed Sutton wrote:
>
>> Allen,
>> Not a lot of hope, short of redesigning the piano.
>> The longitudinal partial is being excited by the combined energies  
>> of the 7th and 8th partials.
>> If you can get the hammer to strike at exactly 1/7th or 1/8th of  
>> the string length, it may reduce the energy enough to stop the  
>> sound. This may be the reason for the old design rule to strike at  
>> 1/7th of the string length.
>> On smaller pianos the longitudinal mode may be at the 17th or 19th  
>> partials of plain wire strings.
>> Ed Sutton
>> ----- Original Message -----
>> From: Allen Wright
>> To: Ed Sutton ; Pianotech List
>> Sent: Saturday, July 12, 2008 6:23 PM
>> Subject: Re: String noises revisited
>>
>> Ed,
>>
>> This sounds like an exact description of what I'm dealing with.  
>> Octave three - 15th partial - disappears with pitch change; all yes.
>>
>> I want to read Jim's book now....does he suggest any fix for this,  
>> or is it a scaling problem (or simply unavoidable) or what?
>>
>> Allen
>>
>>
>> On Jul 12, 2008, at 2:38 AM, Ed Sutton wrote:
>>
>>> Allen-
>>>
>>> If I understand Jim Ellis' book, in a 7 foot grand piano,  
>>> longitudinal mode noises will tend to occur in octave 3, and they  
>>> will tend almost always to be at or near the frequency of the  
>>> 15th partial. There will probably be a slight delay after the  
>>> attack and before the sound develops. If you make slight changes  
>>> in the pitch of the string, the longitudinal mode sound will not  
>>> change pitch, but will disappear when the pitch has changed such  
>>> that the modes that excite the longitudinal mode are outside of  
>>> its resonance band.
>>>
>>
>>
>>
>>
>>
>>
>>
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>

Allen Wright
London, UK

http://www.broadjam.com/akwright




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