[CAUT] killer half-octave

[Ron Nossaman]

Ron Overs wrote:
> Hello Don and all,
> 
> I have a clue as to ". . . why this happened". After considering the 
> structure of these belly rails, I would be very concerned about 
> connecting such a tension device. In my workshop, the solution to this 
> soundboard-perimeter-support-stiffness problem has been to ditch the 
> 'bell' and fit an extra back beam in the treble.

Absolutely, Ron. In addition to the brace, I also put one or 
two 5/8" steel bars through the front of the belly rail, and 
back into the rim for further bracing and mass loading. 
They're epoxied into both the belly rail, and the rim. It 
makes a substantial difference. In any case, the bell goes.


> Another practice which I find baffling is why some manufacturers choose 
> to use weak-and-lossy pine for the connecting strip between the belly 
> rail and the soundboard perimeter support strip across the belly rail. 
> Quite a few manufacturers do this. It would seem to be a wonderful way 
> to cripple the structural integrity of the soundboard's perimeter support.

And certainly seems to live up to that expectation in practice 
all too often. Equally baffling to me is the premise that 
"They must have had a good (acoustical, presumably) reason for 
doing it this way". Seems to me an acoustical reason that was 
indeed "good" would result in more dependably uniform high 
performance when implemented. But then I never did think "right".


> The treble is where we 
> need stiffness and structural integrity, not at the bass/treble cross 
> where the plate horn collects. The 'tone-collector' myth is somewhat 
> ironic, since the practice of running most of the back beams to the 
> cross between the bass and treble makes this area stronger at the 
> expense of the treble sections, which are the ones which really need it. 

But the treble is in the corner, and circles of sound can't 
have corners. The trapezoid of sound is a somewhat less 
intuitive concept, and would need a real explanation to sell 
it. The tone collector, like the centripetal tension 
resonator, has a season ticket to the game.


> If design people would pay more attention to structural requirements 
> instead of pandering to piano-making myth and folklore, we might get to 
> take contemporary piano design somewhere worthwhile while we're above 
> ground. 

Detectable upriver progress has actually been made, against 
all odds, but the boat still has a hell of a big anchor on the 
bottom.


>Please note that these comments are general in application, and 
> not intended to be directed at a single manufacturer.
> 
> Ron O.

Right, just the bulk of the industry that has traditionally 
copied from that hypothetical unspecified manufacturer.

Ron N