[CAUT] FW: Scientific study - Stainless wire (Help!)

[Nancy Salmon]

I am in full agreement with David Porritt. I have thoroughly enjoyed,
thought deeply about, saved for further study, and deleted many of these
convoluted discussions (especially this one and the "what really makes a
piano go out of tune?") Thank you all for your time.
Nancy Salmon
Frostburg State University

On 9/4/07, Porritt, David <dporritt at mail.smu.edu> wrote:
>
>  Jim:
>
>
>
> Please don't take this entirely off-list.  There are some of us who have
> nothing to contribute in that we have no experience with this wire, but our
> interest is high and curiosity even higher.  The last I knew the PTG server
> is capable of quite a bit more traffic before it gets "clogged".  While some
> seem to have an irritation gene that gets activated by certain threads, most
> of us have pretty nimble delete-key-fingers capable of deftly deleting posts
> that don't interest us.
>
>
>
> dave
>
>
>
> _______________________
>
> David M. Porritt, RPT
>
> dporritt at smu.edu
>
>
>
> *From:* caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] *On Behalf Of *Jim
> Busby
> *Sent:* Tuesday, September 04, 2007 11:35 AM
> *To:* College and University Technicians
> *Subject:* [CAUT] FW: Scientific study - Stainless wire (Help!)
>
>
>
> List,
>
>
>
> No offense is meant to anyone by naming several below as "thinkers". What
> I meant to say is that those listed have actively written lengthy posts of
> their thoughts on this study. I will move this thread off CAUT to private
> posts mostly to them rather than clog the list. Sounds really bad, the way I
> worded that. Sorry. (Put foot firmly in mouth…)
>
>
>
> Regards,
>
> Jim
>
>
>  ------------------------------
>
> *From:* Jim Busby
> *Sent:* Tuesday, September 04, 2007 10:26 AM
> *To:* 'College and University Technicians'
> *Subject:* RE: [CAUT] Scientific study - Stainless wire (Help!)
>
>
>
> Thanks, yet again Fred,
>
>
>
> Very detailed observations! About thumpers, it seems to me that the real
> issue in this study would be;
>
>    1. Ability to reproduce the exact stroke w/o variation
>    2. Elimination of "the human element"
>
>
>
> In this regard the Disklavier would be ideal because according to Yamaha
> it can reproduce what the human plays to a 100 point scale. IOW if you hit
> the velocity at 69 (out of 100 possible), the "machine" will reproduce it at
> volume 69 time and time again, as long as the machine has been calibrated
> and not changed during the test time. Of course this precludes human error
> upon reproduction on that piano.
>
>
>
> All the mechanical devices seem moot as to the validity of the testing as
> long as it meets the criteria above. Correct?? At least as far as the
> testing of wire, sound, and acoustic considerations are concerned. But hey,
> you're the braniac here! I'm the farmer who uses bailing wire and duct tape…
>
>
>
>
> Whatever method these guys use will, of course, be posted so it can be
> critiqued. I will pass this along to them. It is still open as to what they
> want to test. Hopefully we will have that narrowed down this week and the
> testing process can proceed. I'll definitely keep you posted. You, Jim
> Ellis, Ric B and Juan seem to be the most active "thinkers" in our pool of
> technicians (ON THIS TOPIC!!) and I'm posting privately to you more than
> CAUT. Jim is especially active in this study. Ric may bring a different side
> to the table with his European influence, and he seems to like to crunch
> numbers,  and Juan, of course, has already done a battery of tests.
>
>
>
> Regards,
>
> Jim
>
>
>  ------------------------------
>
> *From:* caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] *On Behalf Of *Fred
> Sturm
> *Sent:* Tuesday, September 04, 2007 8:16 AM
> *To:* College and University Technicians
> *Subject:* Re: [CAUT] Scientific study - Stainless wire (Help!)
>
>
>
> On Aug 28, 2007, at 8:29 PM, Jim Busby wrote:
>
>
>
> We did devise a thumper, but I'm wondering is a Disklavier would be the
> way to go. Consistency was definitely an issue with our meager spectrum
> studies. I'm really hoping that these "science professors" will take the
> ball and run with it. That is what they do.
>
>
>
> Hi Jim,
>
>             Let me give just a few quick thoughts about "thumpers" and
> other devises for activating a key, to give your physicists an idea of some
> of the problems involved. The tuning test thumper drops a weight from above
> the key. There is a free fall of 6 inches or so before the weight hits the
> keytop. It has now achieved a certain velocity, and is still accelerating
> with gravity (a simple calculation can give the specifics). So far so good.
>
>             Now comes the moment of impact. The key is in a state of
> inertia, as is the whole key/action assembly. During impact, there is a
> period where the colliding bodies "bounce against each other." The weight
> slows suddenly, or possibly stops falling altogether or bounces upward (we'd
> need some high speed videography to know for sure what happens). The keytop
> absorbs this enormous force, which has impacted it suddenly.
>
>             This scenario is far different in many ways from the way a
> pianist plays a key. If he/she plays the key with a great deal of force,
> slamming down from above the key (more or less like the falling weight), the
> difference is that the mass of the body behind the finger will push all the
> way through the keystroke with only a minimal "rebound" effect. And, as we
> have seen in various high speed films, the front of the key will hit bottom
> before the hammer begins to move (flex and compression allows this). But
> this is an unusual piano technique.
>
>             Far more common is simple pressing of the key, starting with
> the finger contacting the keytop, and accelerating the key. This technique
> can be used to create a full range of the available volume of the piano (not
> counting percussive sounds from the key crashing into the keyframe/keybed,
> in that slamming action described above). And I think that any study
> involving tonal output of a piano ought to be based as nearly as possible on
> normal key activation. The problem with using a real live pianist is that
> you can't be sure of exact repeatability, and being exact is tremendously
> important in this area. Joggle a mike, play a little louder or softer, and
> the spectrum and even measured pitch will change.
>
>             Askenfeld (did I get that right? the guy in Sweden who put
> together the 5 Lectures in PIano Acoustics) said in his lecture that he used
> a pendulum to activate a key. This makes some sense, as its velocity at
> impact can be controlled by how far it is allowed to swing (position before
> letting it go), and bounce is minimized because of the oblique angle with
> which it strikes the key. But it is still a rather artificial setup: a body
> in motion suddenly impacts the key, and the arc of movement means that the
> downward movement of the pendulum weight is probably decelerating (a
> pendulum weight moves downward most when it is at the same level as the
> pivot point, and it moves downward less and less as it approaches the
> bottom. Even though the weight is accelerating to that point, the geometry
> is such that its downward motion is becoming less and less). So I'm not
> convinced a pendulum is a good substitute for a finger.
>
>             I guess the disklavier/pianodisc/pianomation systems with
> their controlled solenoids do a reasonable job. I haven't really fooled with
> them enough to have an opinion. It's going to be a sudden electromagnetic
> charge of a controlled amplitude  creating a an electromagnetic attraction
> of a corresponding force. Does this replicate what a finger does? I think a
> finger has more possibilities, in terms of how much acceleration it imparts
> to the key in any given portion of the key travel. (I have puzzled a good
> deal about how it is possible to make one finger's note stand out when
> playing a chord. Somehow that hammer had to be given more velocity. But it
> all happens so fast, and is so hidden in psychology, that it is hard to get
> a handle on it).
>
>             Anyway, I will again say that I think a mechanical devise,
> with a system of accelerating levers activated by a weight, and with the
> mass and placement (leverage advantage) of the weight being variable, would
> be a great contribution to study of any number of things to do with pianos.
>
> Regards,
>
> Fred Sturm
>
> University of New Mexico
>
> fssturm at unm.edu
>
>
>
>
>
>
>
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