[CAUT] Duplex angle

[RicB]

Hi Alan

Me thinks we are getting closer to each others thinking on this.  Lets 
assume we are pretty much in agreement relative to your first paragraph. 
I'll only raise a pinky with regard to the use of the term <<duplex 
noise>> since you seem to distinguish between sizzling (buzzing at the 
capo) and what you refer to as duplex noise.  I'll raise this pinky 
because of what you follow up with in your second paragraph.

When you decide to use the word noise in this context, it strikes me as 
because the front duplex is not working as designed. When it works 
"properly" you say yourself you actually kind of like resulting sound.  
I'd agree myself tho I'll be the first to let that drop into the realm 
of subjective.  But what is it that makes it not work properly....  that 
which prompts you to use the word noise in that instance ?  Do you think 
it has to do with counter bearing angle ? Why would you think that ? Are 
there experiments or data to connect these two thus ?  Not that I know 
of in any case.  Length then ?  Ok... we have quite a bit of information 
floating out there both of the hearsay sort and the more concrete  that 
connects specific lengths to what perhaps we both will agree is 
<<noise>> connected to the front duplex itself and not the sting/capo 
contact area.  But that relationship doesn't have anything to do with 
<<shorter is better>> per se.  It has to do with specific relationships 
between the speaking length and the front length.  Thats no doubt a big 
part of why pitch locks which were invented for an entirely different 
reason seem to have a positive effect on a improperly functioning front 
duplex. Glue too for that matter, as has been stated by several here in 
the previous discussion.

My point is again we have a separation of issues here, and I think we 
are in agreement on that if I understand your post correctly.  I'll put 
that distinction this way.

<<Capo noise>> is icaused directly by combinations of too long a front 
length, too mild a counter bearing angle, and the condition of the capo 
profile.

<<Duplex noise>> comes into play about when the front length shares a 
certain harmonic relationship with the speaking length.

Seems clear to me that going about creating a good duplex is very 
doable.  One needs to arrive at a solution for front length, angle, and 
capo condition that yields minimal capo related noise issues while 
maintaining a harmonic relationship between speaking length and front 
length that does not throw the front length into these whistling / 
noise-ish modes of operation.

McMorrow has a good deal to say on both issues and is definitely worth 
reading.  He's in Seattle... not far from you.

As for how a field tech is to deal with unwanted <<Duplex noise>> (Now 
that we have our P's and Q's nicely separated)...,  I agree 100 %. Tho I 
haven't had the opportunity to try pitch-locks.  Also in concert 
situations we agree.  And thats an important point you make IMHO.  
Sitting on top of an instrument dissecting its sound as a piano tech 
inevitably does is not necessarily the best thing to do in each 
instance.  I would also like to point out that I tend to hedge from 
using voicing in either case unless its my last resort.  Its not really 
a hammer voicing issue IMB... at least not primarily so.  I'd like to 
minimize the problem without taking away from the power of the 
instrument if I can.

A nice exchange of posts Alan. Thanks muchly.

Cheers
RicB


    Ric,

    Thanks for your clarification.

    I make a distinction between what I call string sizzle (buzzing at
    the capo)
    and duplex noise. String sizzle I deal with by reshaping and voicing the
    hammer, mating the hammer to string contact, reshaping the capo to
    get rid
    of a groove. In that order. I deal with duplex noise by hammer voicing,
    using pitch locks in the segment, or glue on the offending
    string(s), and as
    a last resort muting out the segment with a tiny fragment of bushing
    cloth
    woven in that unison right up against the counter bearing bar.

    To me the front duplex adds to the overall sound scape as does the
    back length. I have no objection to this when it works properly, in
    fact I
    like it. But when a higher-than-normal harmonic in the duplex is
    excited and
    stands out and annoys me, I try to deal with it. Same with string
    sizzle.
    But they are different phenomena.

    For me venue plays a role here. On a concert instrument in a larger
    hall, I
    never mute out a duplex segment even if it bugs hell out of me while
    I'm at
    the piano because I don't want to risk dampening projection. Unless
    it bugs
    the pianist too.

    Maybe we are ships passing in the fog here.

    Alan

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