Unison coupling

Ron Nossaman RNossaman@KSCABLE.com
Mon, 24 Jan 2000 07:38:33 -0600


>Hi Ron, 
>Sorry, I don't know what you mean by "pitch drop from
> the attack phase to the dwell."  

* Sorry Ric, I don't have any other way to explain it other than how I
already have. Perhaps someone else will take a crack at it.


> Does the "pitch drop from the
>attack phase to the dwell" need a "tool"  to be measured?  

* Apparently so. You hear the attack phase as noise. So do I, for the most
part. ETDs show a higher pitch in the first half second or so, during that
period where the tuner is mostly waiting for the "noise" to dissipate so he
can get on with it. I often tune unisons by listening in that attack phase
and hitting the key rapidly. It may sound like noise just listening to it,
but when you try tuning in the first half second of the attack, you'll find
that it's pretty well organized noise.


>If so,
>how does that measuring tool stand up to other measuring tools? 

* Which other measuring tools? Personally, I haven't made direct
comparisons between all such available tools. Even if I had, and having
chosen what I considered the best of the lot, I still couldn't prove it was
"right". Let's ask around among the list folk and find out if users, or at
least owners, of all the available ETDs register a pitch rise in the
attack. Correct me if I'm wrong, but I don't think all the machines out
there work by exactly the same method, so similar results among the
machines ought to constitute acceptable evidence, at least for me. If
that's not good enough, you can probably pick up a reasonably decent
oscilloscope for less money than a high end ETD costs and find out for
yourself. I, for one, would certainly be interested in hearing about what
you come up with.


>	A wild hunch suggests that "attack phase" is mostly noise, from
>transitory shock waves resulting from the moment of impact of the
>hammer, lasting milliseconds until the frequency of oscillation of
>the piano wire is established. ---ric

* Entirely possible, but the pitch rise I measured in one string in octave
5 took about a half second or so to drop to the dwell frequency, not a few
milliseconds.


Ron N


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