This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Hi all Ric Moodly brings up a point about buzzing which as far as I've understood has always been the major concern with attempts to find an alternative to the conventional bridge pin configuration. I've never really heard much convincing argument against agraffes beyond this concern through the years. As far as the mass of the agraffe is concerned. I would suggest that the string sees as much (if not more) the total mass it has to move rather then the mass of any individual componet in the bridge/soundboard assembly. That said, agraffes conceivably could be used conciously with regard to local impediance concerns. A point about the vertical vibration claim that seems to be rather foggy in the discussions is just what this claim is really about. A couple things might be worth to remember. The impact of the hammer causes a traveling wave to initially be set up on the string which eventually dissapates into a standing wave. During that initial period however the pulse traveling up and down the length of the string is reflected by the endpoints, and the direction of reflective force is with out a doubt influenced by the orientation of the termination. The hammer sets a vertical pulse (wave) in motion that smacks into the bridge termination in an upward direction. The bridge termination repels much of this pulse back down the string, and exerts a directional force of its own. The pulse itself has its own inertia and wants to continue on the same initial plane. As I understand it, the Stuart claim is two fold. First, that the vertical termination point at the bridge is conducive towards lengthening the time period this vertical component is evident. Second that this exact lengthening is reponsible for an overall lengthening in the sustain of the instrument. Math proofs aside for the moment, intuitively there is support for this idea. The physical motion of the bridge / soundboard is dominated by an up/down vibration. A deflection of any string pulse in any other direction then an upwards/downwards orientation will not only waste energy of the string wanting to continue its up/down vibration movement, but it will also exert that same directional force on the bridge/soundboard... essentially attempting to vibrate the soundboard <<sideways>> as it were. There has simply got to be some loss there. If all componets to the greatest degree posible exert forces on the vibrating system in the same direction (i.e. upwards/downwards) then less (string) energy will go into dealing with any resistance to this same motion. Less lost string energy would mean more for the system to process into airborn soundwaves. Of course there are a lot of contributing factors to why this vertical traveling pulse dissapates and eventually leaves the string vibrating in a somewhat ellipitical standing wave. End conditions, string consistancy, interference of the two initial traveling waves on each other... etc. Point being that loss is built into the system no matter which way you look. But vertical termination purports to reduce one of these loss components to a degree significant enough to increase the overall output of the strings input energy ... or said elstwise... increase sustain. Since the math evidently backs it up and there is to date nothing concrete that remotely refutes the claim, I think it should be looked at with great interest instead of skeptism. Working on the <<buzz>> problem of vertical terminations should be more on our minds then anything else. Just a few thoughts from over here :) Cheers RicB Ric Moody writes /Your pictures show an interesting concept of how to keep a piano string from buzzing on top of the bridge (without to much down bearing) . Is this an agraffe on the bridge? How is it actually mounted? Threaded, or driven orglued? How does this sound? It must be acceptable as in better than digital. These days most digitals are beginning to sound better than most grands under 5'2" at least through loud speakers (including sound reinforcement). The other concern (theoretical) is that a string resting on a bridge by itself transmits its vibrations directly. A string going through a big brass agraffe must also move the mass of that agraffe which might be many times more than the string itself so I wonder what the acoustic or sonic effect might be? I would love to hear it because it seems such an object might be made to solve the problem of down bearing controlled to .001 inch for each string. Ric Moody/ ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/d1/68/b7/a5/attachment.htm ---------------------- multipart/alternative attachment--
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