Bass strings changing scale

[John Delacour]

At 10:48 AM +1100 12/3/01, Overs Pianos wrote:

>A few of us have been using 'Z' as a guide for some time. While it 
>is sort of black art as you say, its considerably better than 
>building something then seeing which way the wind blows. 
>Furthermore, once you've had experience with it you may find it 
>useful as a guidance tool for future projects, or if it turns out to 
>be a waste of time as you suspect...

In the absence of any solid information from any quarter as to the 
_application_ of the principle, I am ill-equipped to judge. 
Interested in the concept, I sought clarification by asking making 
specific requests ...

At 1:31 AM +0000 12/2/01, John Delacour wrote:
>By the look of it you will get Zg rising steadily as you proceed 
>down through the bichords from say 7 to 11 for argument's sake, and 
>then what?  Will you go for 11+ on the top single and continue the 
>curve? If so, then it seems you require an even bigger jump than you 
>said a while ago


At 5:30 PM +0000 11/22/01, John Delacour wrote:
>This would all be a lot easier to grasp if one of you would make a 
>sample scale available, not that the principles are hard to grasp 
>but that an actual string scale would make it clear how you apply 
>them in a certain case.  If these are not trade secrets, I for one 
>would love to have a spreadsheet doc of one of your scales.


... and got no responses.  You both make claims for the method and 
then refuse to give any worked example or clear explanation.  I asked 
the questions because I want to know more.  Theodore Steinway licked 
his finger, held it to the wind and capped the bridge at the treble 
with box, decades before the word impedance existed and probably a 
century before it migrated to acoustics.  You now suggest that there 
is a formula that would have made that design choice more 
predictable.  Well, I'm interested and I want to know how that 
formula or at least the guiding principle is applied.  I began by 
expressing interest and my scepticism grew as any practical 
explanation failed to appear.

In designing strings for existing bridges I take account of a number 
of factors such as tension, wire stress, copper/steel ratio, 
undercover/top cover ratio etc. etc. and I make no mystery of it. 
Naturally a few thousand sets of bass strings down the line, 
experience has taught me which principles are to be applied to which 
types of scale and I can tell you the range is pretty wide.

I would be only too happy to have that experience and intuition 
expressible in usable formulae, since it would allow more complete 
automation of the design process, save me perhaps three minutes on 
the calculation of each set, and extend my understanding of the 
principles I work with, just as I am keen to understand the effects 
of longitudinal vibration or the reasons whipping works.

If I had based my practice on Wolfenden's guidelines when I started 
making strings and continued there, I would have made far worse 
strings.  His work generally was most useful in his day, but when he 
came to bass strings he was out of his depth and had not the breadth 
of experience.  As a result he theorizes on the basis of received 
knowledge from men in the field and gets things wrong.  The same goes 
to some extent for a well-known German of our day and for anyone I've 
seen write on bass strings.

I've no reason to doubt the sound quality of your pianos.  I have 
come across and own Schiedmayers to die for, but I cross myself 
before I string them and would not dream of imitating their scales. 
Just give me some solid info as to how you apply the Z formula and 
publish a bass scale that uses it.

JD