Grand piano design - parallel vs angled strike line?

[Ron Nossaman]

>> I know a lot of this kind of thing has already been done,
>>but I don't know how exhaustive the experimentation was, or how one would
>>find the information.
>
>I'll bet that speculation far exceeds testing for most of us 
>(corporations included).

Yes, unfortunately, and there's the rub. It's tough to get an education and
not starve in the process.


>>  I can't imagine a designer giving even a passing
>>thought to whether it's easier to reach tuning pins or not.
>
>I have with our designs, but I have no idea how widespread such 
>considerations are.

Well bless you sir! That has to be a rarity. Now if we could talk a local
dealer into carrying the product, I'd love to service them.



>I don't believe manufacturers should be using an existing box when 
>drawing up a new design. We've little hope of coming up with a 
>wholistic new design if we're stuck with 'last decade's' rim design. 
>While budgetry constraints can dictate such a course of action, we 
>should endeavor to move our industry beyond the mediocrity of 
>repeating the past.

I don't believe they should be either, but my suspicions are otherwise,
given the reverence held for past mediocrity.



>This whole matter of string terminations is desperately in need of a 
>rethink. I can't abide these rattling trebles that we've been stuck 
>with over the past century. Often, the string length in the front 
>duplex is too long (what's worse, some makers try to make them 'in 
>tune' with a harmonic), and excessive lengths from the pin to the 
>counter bearing make a bad situation worse.

Here here! I had yet another two octave squealer in a very expensive new
piano just Friday. It's about to quit being fun. 



>I presume that you mean 'belly rail' (is this the correct US 
>terminology?) when you mention 'rim'. But I still wonder if the 
>flexibility around note F#70 might be improved if we minimise the 
>necessary compromise which the dampers force upon us? What do you 
>think about the approach I have used with my 170? (he writes as he 
>leaves himself exposed to unbridled cannon fire).

Yes, I'm sorry, I meant the belly rail. Functionally, it is part of the rim
to the soundboard and I tend to conceptually lump it in with the rest of
the rim. It's the result of being simple minded, and just part of the
problem of translating what's going on inside my head into a semi-coherent
communication. I like what you did with the 170 belly rail. Smooth
transitions tend to blend stresses over a broader area, and I'm all for
that. It's very pretty. I'm curious about the damper wires going through
the belly rail though. I've wondered about doing that, but haven't yet
tried it. Is the belly rail undercut far enough to clear the wires part way
down it's face, to keep from having to maintain wire clearance through the
full length of a 100mm hole and make the hole easier to bush? If so, do you
lose enough stiffness there to kill some of the sustain the dampers were
necessary to contain in the first place? If not, how do you line everything
up and get the hole bushed? Just drilling a small diameter hole that deep
through maple, it's nearly impossible to control where it comes out at the
bottom. At least it has been for me. This came up a few times in years past
building player stacks and such, and I finally had to make spoon bits of
the appropriate diameter and length to control drift. This isn't a
criticism, you understand, just some of the thoughts I went through when I
considered doing this.   

Also, if I may, the soundboard problem (as opposed to the duplex problem)
in the killer octave is mostly too much flexibility already. That's also
why this is where zero or negative bearing and crown are noticed first and
most often. Stiffer ribs, machine crowned, make a tremendous difference
over the panel supported flat ribbed compression crowned system in which
the killer octave is at it's worst. Getting the bridge as far away from the
belly rail and as near the center of the soundboard as possible, so it CAN
move, then stiffening the crowned ribs to both support string bearing and
control the movement (raising impedance and resonant frequency to slow
energy transfer and increase sustain), gets you most of the way there.  



>Once again the tech' gets the blame for a problem which stems 
>entirely from a poorly conceived scale (I have had this happen).

Likewise, and with a customer that has trouble with the concept of humidity
swings in the first place, it's hard to break even. 


>Apologies for my concluding digressionary rave. I shouldn't stay up 
>writing so late. It causes my diplomacy filter to malfunction.

No problem here. 

Regards,

Ron N