Conservative Octaves

[Bill Ballard]

Don't worry Stephen, this is a nice neaighborly group, and we don't
"ticket" our fellow members. Except Ron Torella fines you if you do a
dumb post and insist oncopying the entire post it refers to.
Nice post, though, Stephen. I might have something to say on it later.

(Sorry, Ron, but some people still don't know what your talking about.)

Bill Ballard, RPT
NH Chapt.

"If we see you SMOKING we will assume that you are on fire and will take
appropriate measures".......Sign in a Music Dept. Hallway

On Thu, 24 Oct 1996, Stephen F Schell wrote:

> Hello List!
>
> I have been reading the mail for the past month or so, and have enjoyed
> it a great deal. I thought I'd weigh in on the octave stretching
> discussion.
>
> My general strategy is to widen octaves as much as possible throughout
> the piano; the limit being the point where the single octave becomes too
> noisy, usually at the 2:1 level. This, for me, is between 1/4 and 1/2 bps
> (except the high treble and low bass), depending on the piano and how it
> is voiced. The idea is to battle the tendency for the scale's
> inharmonicity to seriously mistune the partial coincidences, which can
> do much to strengthen the tone  if they are in close enough agreement.
>
>
> Reinforcement of the piano's sound from coincident partials is a powerful
> phenomenon. One can demonstrate this by "ghosting", i.e. playing a note
> briefly while silently depressing another note containing partials
> coincident to the note being played. The partial(s) excited this way
> will sing out, often loudly. It's no wonder people often refer to the
> sustain pedal as the "loud" or "swell" pedal.
>
> Look at it from the perspective of a note on the piano, say C6. It's
> first partial coincides in frequency, more or less, with the second
> partial of C5, the third partial of F4, the fourth partial of C4, and so
> on. The higher the inharmonicity of the scale, and the more
> conservatively one expands octaves, the more these coincidences will
> disagree, becoming progressively sharper to C6 down the scale. Even with
> an aggressive stretching tactic, the inharmonicity wins eventually; the
> 16th partial of C2 may coincide with the first partial of C6 on paper,
> but is often 40 cents or more sharp on a real piano. This is okay,
> though; such a high partial may not be able to generate much sound
> anyway. What is important is to maximize the agreement of those partials
> which can contribute significantly. For my money, those are the octave
> (2:1), twelfth (3:1), double octave (4:1), and triple octave (8:1). At
> least those are the ones I have learned to pay attention to.
>
> So how does one achieve a tuning where these coincidences can sing in
> harmony? By expanding the octaves the maximum acceptable amount
> throughout the piano. I generally like to set double octaves (at 4:1
> level) about 1/2 bps wide throughout, except for the upper treble. I aim
> for a pure twelfths all the way up, which usually results in a double
> octave which becomes pure by about C7, then progressively but gently
> narrow in the top octave. Triple octaves often remain pure to C7 or
> higher, then likewise turn narrow. This seems to provide the top few
> notes with maximum reinforcement; the octave is wide maybe 4bps, the
> twelfth is pure, the double octave is narrow maybe 3bps.
>
> I find that the pure twelfths approach seems to squeeze the most from a
> piano's treble. Compared to the pure double octave tuning I did for
> years, the sixth octave is expanded more, which really helps those
> pianos tending to weakness in this area.
> Sometimes, though, a compromise is necessary on a few notes around F6,
> where a pure twelfth overstretches the double octave. In the top octave,
> 2:1s beat wide only a few bps, instead of the gritty buzz that can
> develop in them with pure double octaves.
>
> Carl Lieberman taught me a great tuning test years ago. He likes to use
> both hands to play four neighboring positions of the same note ( i.e.
> A3, A4, A5, A6) simultaneously, let them sing for a moment, listening
> for whatever develops in the mix of sound. There are a great many
> partial coincidences shared among those four notes. What is desired is
> an overall solid sound, with a minimum of grumbling disagreement. This
> test is useful anywhere on the piano. Curiously, an aggressive
> stretching tactic will generally yield the smoothest and most powerful
> sound with this test.
>
> Does anyone around here hand out tickets for being verbose? Hope not.
>
> Steve Schell
> stfrsc@juno.com
>
>
>
>