Duplex

[Overs Pianos]

Dale, Dan, Del and Ric (Moody),

Dan wrote:

>May I remind you that this is not my idea; it is, was and always will
>be CF T Steinway's, who has the original patent, 126848.

Del wrote:

>What can I say? Lots and lots has been learned about the piano and 
>its design since old CFT sat in front of a drafting table. Smart as 
>he was, he wasn't perfect. Nor was the piano he created (in spite of 
>the claim of certain of his descendents). It was--or should have 
>been--just one stepping stone on the path, albeit a significant one. 
>If our industry is to survive,  however, we must learn from both his 
>experience and our own and then go on from there.

Exactly Del well said, and progress in piano design and construction 
has been basically hi-jacked by Steinway's dominance of the market, 
and their incredible arrogance, over the twentieth century. Today, 
even if their products are not cutting edge, many seem incapable of 
allowing themselves to notice. Enough of that !

Well certainly Dan, Steinway had the original patent for duplex 
scaling. But did it achieve what has been claimed ad nauseam ever 
since. Almost certainly not. A front duplex which has been carefully 
set to a harmonic length of the speaking length is a sure way to 
build a lousy sounding note. The duplex length must be detuned to lie 
in between two adjacent harmonic lengths. Further, the duplex length 
must not be too long or it will be noisy anyhow, even if it is a 
detuned length. Therefore, a suitable detuned length must be chosen 
for each section of speaking lengths. We build a spreadsheet for the 
purchase, upon which a column is provided for each detuned length 
option to be calculated. The general formula I use for these options 
are;

  Detuned length option = (((lower harmonic length)/(next higher 
harmonic length))^(0.5))*(lower harmonic length)

I trust that I've got all the brackets correct, since its written off 
the top of my head without consulting one of my spreadsheets. I have 
no idea if Harold Conklin or others have used this formula for their 
calculations, because I worked this out on my own just before 
building no. 003 to bring it Reno (no. 003 is front duplex detuned 
and rear duplex tuned). But since all roads lead to Rome, its very 
likely that others before me have used it also.

The formula will allow you calculate the length of a duplex which is 
in-between two adjacent tuned duplex lengths (which we wish to avoid 
like the plague).

There you go all, out with your spreadsheets. I know it's right 
because I've actually gone to the trouble of building a piano with 
this system and it works. String noise might suit those who are hard 
of hearing but I don't care for it at all. Steinway might have the 
patent for tuned duplex lengths but who wants it? It only  results in 
noise. I'm more interested in clean tone. Anyone else wish to join me?

Ron O
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Website:  http://www.overspianos.com.au
Email:        mailto:ron@overspianos.com.au
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