S&S D Duplex

[Richard Brekne]

A couple comments in between Phil

Phillip Ford wrote:

>
> > > Agreed.  But how to go about locating the
> > aliquots high in the scale?  Since
> > > you can't do it by listening you have to do
> > it by measuring or comparisons to
> > > locations lower in the scale.  This is not
> > 'tuning' the aliquots.
> >
> > First of all, why not ? We "Tune" pianos all
> > the time without listening to them...
> > ETD's.
>
> My point was that to tune these you would have to move them until the duplex
> frequency matched some reference - either your ear or your ETD.  Just locating
> by measuring would probably not do it.
>
> >Secondly, if the desired longitudinal
> > results when the backlength is tuned
> > such that transverse frequencies are harmonic
> > to the speaking length, then you can
> > use the transverse frequencies to get to where
> > you want to go.
>
> That's true if there is such a correspondence.

Well, thats  one of the things I suppose needs clearing up. Because as you point
out, there seems to be some apparent  disparagy between the patents claims
relative to L-waves and the use of Transverse relationships to tune the
backlength. This was just the only such explanation I could think of. Seemed to
fit well with what Sarah had to say, and could easily fit the kind of empiri based
methodology available to Mr S. way back then.

>
> > Actually, as I read the whole thing... this is
> > exactly the "matter" the entire
> > duplex system is about. Namely bleeding off
> > some of the energy imparted to the
> > strings speaking length in such a way that
> > sustain is increased while tone is not
> > detrimented by this nasty whislting sound.
>
> If the duplex actually accomplished this then it would seem a positive thing.
> I think it's still an open question as to whether sustain is increased.  As to
> this whistling sound that you and CFT hear, I'm not sure I've heard it, or if
> I did didn't recognize it as such.  Perhaps you could tell me a little more
> about that.

Well, its easiest to hear in conjunction with the front duplex. Sometimes its so
darned annoying it just makes the piano useless IMO. Getting used to that hearing
that component of piano sound (when present) tho, you can start picking it out in
back lengths as well. You know its there (in the back length) if it dissapears
when the segment is muted. At odds with the present explaination is that in my
experience you need to mute large sections of the back length to really get rid of
the effect... tho that may just be a result of my own inexperience in fooling
around with the backscale.

>
> > Ed McMorrow has some interesting things
> > to say on this in his book as well.
> >
>
> I've heard his book mentioned before.  I don't think I have it.  What's the
> name of the book?
>

"The Educated Piano" I believe. Ed is in Seattle, his address is available on the
PTG homeside, and his book is still available from him directly (at least last I
checked). Its well worth a read regardless of the controversy surrounding his
advocacy of extremely light weight hammers.

>
> > Another enlightening experiment is to simply
> > mute off all duplex lengths, front
> > and back on a Steinway. Boy what a change and I
> > cant say its for the better
>
> I've never tried to argue that the duplexes have no effect on the sound.  I
> know that they do.  And  having them tuned vs untuned will affect the sound as
> well, although perhaps less noticeably than having them there vs not having
> them there.  I think the discussion is about whether having them tuned gives a
> 'superior' tone and better sustain.
>

We keep getting into this about sustain, and it would seem an easy enough thing to
measure. I suspect we need also to specify better just what it is that is
sustaining... the individual tone completely isolated from the rest of the string
plane ?? or as a part of the whole. One thing "seems" clear to me. Muting off the
back length in most pianos not only "deadens" the sound a bit.. but it gives me
the distinct "impression" that the sound in general is more short lived. I really
liked Sarahs comment about "working with the energies" involved instead of against
them. Seemed to make perfect sense to me anyways.

>
>
> Phil F

Cheers

RicB

--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html