[CAUT] RE : Quick fix Duplex was duplex

[Fred Sturm]

On Oct 31, 2006, at 12:51 AM, ed440 at mindspring.com wrote:
> Needle the capo side of the hammer, almost into the strike point.
> Ed Sutton

And check string level and mating. I think Ed's suggestion is an  
excellent one, based on experience. I think the reason it works is  
because the level and mating weren't quite perfect.
	I also move the string back and forth, if this doesn't work, based  
on the notion of tiny metal shavings on the capo causing the noise. I  
move the string back and forth using a prying method: screwdriver  
blade inserted between capo and string from the duplex side, grabbing  
the string with the corner of the screwdriver blade, twist the blade  
so that the other corner of the blade is bearing against the capo,  
and ease the string over. You are prying downward, relieving pressure  
on the capo from the string, so that you don't "plane up" more metal  
shavings.
	Check if it is at the bridge pin, by bearing a screwdriver blade on  
the pin while playing the note, and also on the offending string  
itself ahead of the pin. What to do "on-site" while tuning if this is  
the problem? If the pin is loose enough, try rotating it a bit, so  
the possible shaving on the pin is away from the string. Dose the  
base of the pin with thin CA.
	And, of course, the already mentioned lower tension and pull it up  
on the other tuning pin, to move the string itself through the  
bearing points. And then address both strings at the bearing points  
to re-create positive bends, for tuning stability, tone, and to level  
the strings again.
	In the interest of avoiding such noises and what I have found to be  
the causes of them, I like to space my strings pretty carefully  
before bringing them all the way to pitch. Do it with the strings  
taut, but so that you can move them pretty much with a strong  
fingernail. Any final spacing touchup is done as above. On pianos  
where I have re-strung the capo sections, with new bridge pins,  
dressing the capo, and the above string spacing method, and with good  
string leveling and hammer mating (with travel and square  
understood), I am not plagued at all by objectionable front duplex  
noise.
	Now I confess I haven't tried this on a Young Chang PG-213 (more or  
less Steinway B copy), which has the nastiest front duplex noise  
problem I have ever heard. I've seen a few of these, all with the  
entire front duplex completely muted. Decided to see what it sounded  
like with mute out one day. Wow! But, then again, I haven't done any  
of the meticulous prep work on it, so maybe it can be made not so bad.
	
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu

>
>> OK guys,
>>
>> This is mostly something that should be looked at and taken care  
>> of with
>> restringing. Now, what do you do when the buzzing is getting in  
>> the way
>> of a clean good sound and you're just there for the tuning. Have  
>> any of
>> you found reasonable fix for this buzzing?
>>
>> My first tentative is to move the string side to side on the capo and
>> sometimes on the front duplex as well. If no change happens (which is
>> rare) or the change is not enough, I now try the "pitch lock" on 2 of
>> the 3 strings (I try to find which one is the worst to start  
>> with). Now,
>> if this doesn't work AND the piano is NOT in a concert hall, I  
>> will on
>> occasion mute the whole thing. For concert hall pianos, I will  
>> mute the
>> whole front duplex (temperament felt)if it disturbs my tuning and  
>> then I
>> will remove my mute.
>>
>> Any other ideas ???
>>
>> Marcel Carey, RPT
>> Sherbrooke, QC
>>
>

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