ETD Unisons was something else

[Kent Swafford]

on 3/20/01 5:23 PM, jolly roger at baldyam@sk.sympatico.ca wrote:

> On a piano with quite a number of false strings, I will
> often pluck each unison and get all 3 strings stable, just using the RCT.
> While the unison may sound slightly off, 2 weeks later it will tend to
> sound better than the unison that you had to search for a "sweet spot" by ear.

Hi Roger,

While I'm not suggesting that it would be the same for you, if I were doing
the tuning as you describe above, my hammer technique would be better when I
was tuning each string to the ETD; my hammer technique probably gets a
little fuzzy during the final aural tweaking, and would tend to explain why
the aural tweaking doesn't last like the ETD-tuned unisons. I agree, BTW,
that tuning all 3 strings as stable as possible will result in good, not
perfect, unisons with little possibility of a "gross" error.

Back to Richard Brekne's original topic - Robert Scott and Dean Reyburn, ETD
developers, have provided some guidance on tuning unisons with an ETD.

Dean points out that, to an ETD, there is no difference in the effect on an
ETD display between mis-tuned strings within a unison and false-beating
(wildness) in a single string. They are pretty much the same thing, that is,
more than one frequency sounding at once.

Then Robert Scott adds:

> on 6/21/00 10:08 AM, Robert Scott at rscott@wwnet.net wrote:
>> Speaking for TuneLab, I can tell you that the phase display will be
>> somewhat erratic if there are really three different frequencies blended
>> together.  Once the three pitches have been mixed together they appear
>> to TuneLab to be the same as one tone that is wavering in both pitch
>> and amplitude.  You cannot draw any conclusions about the average pitch.

To me, these comments from Dean and Robert suggest another reason why
ETD-tuning of unisons may be unreliable -- if more than one frequency is
present at the partial level at which the ETD is listening, be it from a
wild string or from two different mis-tuned strings, the effect on the ETD
display is somewhat unpredictable and the display is somewhat unreliable. In
other words, although unisons made up of very clean-sounding strings may
sound find when the three strings are carefully tuned separately to an ETD,
false-beating and mis-tuned unisons clearly can "fool" an ETD.


Kent Swafford