[CAUT] Baldwin SD-10

[David Love]

Long, low angled duplexes are more likely to lose energy (leak and make
noise) than short, low angled duplexes.  That's pretty demonstrable.  Noisy
duplexes (where there is leakage) have demonstrably less power and sustain
than non leaking duplexes.  That's also very demonstrable and seems like
pretty simple stuff.  There seems to be an optimum combination of length and
angle that reduces leakage and doesn't cause excess drag or wear on the capo
bar.  Fandrich has quantified this in some previous writings, I believe.
Added mass in the capo bar always seems to help with loss of energy.
Minimizing loss of energy appears to help with both power and sustain.  I
think it would be a march of folly to try and create a counterbearing
situation that optimizes the amount of leakage in the hope of having some
reflected back to the speaking length.  I suppose that's personal opinion
though I like to think of it as common sense.    

As far as the Grotrian goes, my only comment is that it's hard to isolate
variables.  When a complete rebuild is done, it's not always possible to
tell whether the change in tone is due to a change in some particular item
or whether it comes from some combined effect from several changes.  My
experience (anecdotal evidence of course) from having changed many Steinway
counterbearing areas and left most other things alone (except for new
strings, bridge renotching, and capo shaping) is that there is no noticeable
change in the character of the tone, however there is a noticeable change in
the clarity, power, sustain and propensity for leakage.  That might be heard
as a change in tonal character but I don't consider it one.  Rather, it
seems more like a mechanical optimization of what's already there; tonal
changes, in this case, being limited to changes in soundboard response.
Whether or not my "perceptions" constitute absolute proof in pure scientific
terms, I'd have to say they don't and could be construed as a simple matter
of opinion.  

David Love
davidlovepianos at comcast.net 
www.davidlovepianos.com

-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of RicB
Sent: Monday, October 23, 2006 10:27 AM
To: caut at ptg.org
Subject: [CAUT] Baldwin SD-10

I was not aware that anyone had shown that all, most, or any given 
amount of energy that bleeds through to the front duplex is "lost"  one 
way or the other. Tho I would love to see some study on the matter.  
That vibrating energy can get reflected back through the front 
termination is beyond question IMHO.  Easy enough to show by simply 
plucking on the front length and listening for the singing length to 
come into vibration. Sustain is said to increase, at the expense of a 
bit of volume... the usual trade-off

There are IMHO two issues with the front duplex.  String noise created 
by the condition of the termination and counter bearing parameters, and 
the nature of the tone the front duplex length creates.

Leakage occurs anyways.  Regardless of termination configuration. It 
would suprise me to see it shown that one or another termination 
configuration would loose significantly more energy in the form of heat 
loss.

As for your closing comment.  You should see the Grotrian Steinweg that 
was rebuilt by Bechstein I've written about.  I assure you ... the 
choice of front duplex has a profound affect on the kind of sound 
produced by the instrument

Cheers
RicB

    Not sure I would agree with this.  Loss of energy to the front
    duplex in the
    form of heat is simply lost.  It will not be stored in order to be
    reflected
    back to the speaking length.  The idea of the tuned front duplex was
    that it
    would vibrate sympathetically adding something to the overall tone.  In
    reality, the sympathetic tuning actually encourages leakage and loss of
    energy.  Detuning the duplex or shortening it or increasing the
    counterbearing angle or increasing the mass in the capo bar (as in a
    Boesendorfer) or some combination of all of these discourages "leakage"
    reducing the potential loss of energy in that section.  

    Differences between pianos in the sound in that section are more likely
    because of differences in hammer/soundboard interactions than duplex
    design.
    This is evidenced when one makes an alteration of an existing
    counterbearing
    area, say in a Steinway.  There is no significant change in the
    overall tone
    but the tendency for leakage can be greatly reduced.  

    David Love
    davidlovepianos at comcast.net
    www.davidlovepianos.com