Understanding Duplex Tuning and placement.

[Michael Jorgensen]

Hi Phil,
      Your C7 numbers matched mine except mine were flatter, or closer to one
half step sharp of the consonant interval of the speaking length rather than a
whole step sharp.  This is C7 F 11 # 5171411 which is a marvelous instrument.
One thought is that when they are one half step sharp, because of side bearing
they are more opposite the speaking length of the next note on the bridge.
Perhaps the Yamaha experts can give us some answers.
      This piano was just voiced by the head tech from the Yamaha Concert Grand
factory.  His name is pronounced "Hori" but I can't spell it or find his card
right now.  We were visited by the Yamaha Team this year, who worked on our
newish Yamahas and made them sound fabulous.  This C7 really shines.

-Mike Jorgensen
Central Michigan University

-Mike Jorgensen

Phil Bondi wrote:

> Today I tuned a Yamaha C7 for the 3rd time this year. The piano is a
> wonderful instrument, and a good candidate for my experiment. The experiment
> being..I wanted to find out what notes were being sounded a certain part of
> the duplex section..and why. I kept my sample section small - I only sampled
> the notes from B4 to F#6, which on this piano covers from strut to strut of
> the upper tenor/lower treble section. I did the experiment after I was done
> tuning. Here's what I found:
>
> The 'sound' or the 'notes' being 'excited' in the duplex section don't make
> any sense to me. I really want to understand this to better understand why a
> piano sounds the way it does, or doesn't, depending on your perspective.
>
> Hopefully, the following chart will make it through so anyone reading this
> will understand it..the first note will be the actual note on the piano, and
> the second note will be the 'sound' coming from the duplex when plucked. The
> + or - in the parenthesis following represents where the duplex sound is in
> comparison to the actual tuned note..+ = sharp ..- = flat. If there is no +
> or -,  then, to my ear, it was in tune, or really really close where I
> didn't think there was a measurable difference.
>
> Here goes:
>
> B4 - C#7(-)
> C5 - D7(-)
> C#5 - D#7(-)
> D5 - E7(-)
> D#5 - F7(-)
> E5 - F#7(-)
> F5 - C#7(+)
> F#5 - D7(+)
> G5 - D#7(+)
> G#5 - E7(+)
> A5 - F7(+)
> A#5 - F#7(+)
> B5 - G7(+)
> C6 - C#7
> C#6 - D7
> D6 - D#7
> D#6 - E7
> E6 - F7(+)
> F6 - F#7(+)
> F#6 - G7(+)
>
> You'll notice at F5 and C6, there was a big change in the duplex note from
> the previous note..this is where the hitch pin configuration changes, also.
>
> The recent thread on Duplex tuning only had me mildy interested because,
> frankly, I was real busy with other things..but I remembered it and it got
> enough of my attention to try an experiment when time allowed.
>
> For those that don't know, the C7 has a similar "Steinway-style" duplex
> configuration, as opposed to Baldwin's older individual aliquots.
>
> I would think that the sound coming from the duplex would better represent
> something from the partial series for that particular note..that's what I
> "think"..that doesn't necessarily mean I am correct or I'm even close..I
> know very little about Piano Manufacturing or how a piano gets scaled,
> and/or why..I am interested in finding out why these particular notes'
> duplex sound what they sound..and are they correct..and if they're not
> correct, how does one correct them after a piano is tuned and not mess up
> the tuning, and shouldn't you tune the duplexes AFTER you've tuned the piano
> and won't that mess up the tuning?!?
>
> With this type of configuration for a duplex, how can you effectively change
> one duplex without changing all of them, to a certain extent?
>
> Having recently re-built a Baldwin R with the individual aliquots, I can
> understand how and why that system might work a whole lot better now than I
> did when I re-built that R. So..how can you effectively change the duplex
> sound for one of the 'Steinway-style' duplexes and not change all of them?
>
> Am I out in Left Field?..did I have too much time on my hands this
> morning?..is there any validity in what I am asking?
>
> Phil