Backlengths

[Ron Nossaman]

>>Is there any rule of thumbs about maximum back
>>lenghts ? Effects caused by pushing that evnt. border ?
>
>>Richard Brekne
>
>This is an interesting question.  Most of what I have
>seen on the subject seems to indicate the more the merrier.
>And probably anyone actually building a piano isn't going
>to explore the upper limits because they aren't going to
>put a 2 foot backscale in a 6 foot piano for various
>reasons such as it doesn't look like anything you've ever
>seen before. I assume that you get more flexibility or
>freedom of bridge movement as you make the backscale
>longer. But it's probably not a straight line relationship.
>It's probably a curve that starts off steep at first and
>then starts to roll over and eventually levels off (becomes
>asymptotic if you like).  It would be interesting to know
>where this curve levels off.  Also I'm assuming that the
>backscale cannot get too long.  You just stop getting any
>benefit after some point.  But I don't know this.  Maybe
>there are some negative consequences of making it too
>long (other than it just taking up a lot of space). I
>await the results of your research project.
>
>Phil F

>From a soundboard restriction standpoint, anything longer then the speaking
length is useless, obviously. The longer the back scale is, the more likely
it will be to make noise, especially in the more flexible areas of the
soundboard like the mid to low tenor. Hence the string braid. Of course,
I've seen many a factory installed tuned rear duplex bar in (factory)
braided off sections of the tenor. Very confusing. If it's there, it should
be tuned, right? Isn't that the mantra?

Ron N