---------------------- multipart/alternative attachment Hello bewildered backcheckers, My WAG on backcheck height adjust increases volume. We know the only thing that affects volume (in an otherwise prepared=20 piano) is velocity of the hammer. So how can adjusting backcheck height=20= to 2mm below hammer tail affect hammer velocity? It seems from what has been=20 written so far is that invariably the height of the backcheck is being=20= lowered. We know that the position of the backcheck is near as far at=20 the end of the teeter totter as we get (excepting the damper 'stack')=20 AND that the backchecks relationship to the key is 'tangential?' (it=20 swings in an arc leveraged by the point at which the backcheck stick=20 intersects the key). The effect of bringing the backcheck closer to the=20= key places the backcheck closer to the balance rail AND diminishes the=20= tangential relationship of the check. Possibly this allows the hammer to be accelerated faster for any given=20= input (but probably more so at soft play)? Renewing backchecks would=20 have the same effect because of proper height adjustment (rather than=20 because they are new). An easy way to check this effect might be to see=20= what happens if the backcheck is removed altogether. )No, I didn't=20 check any of this out because risk taking is so much more entertaining=20= :-))) Best, Rich Olmsted On Thursday, May 29, 2003, at 03:34 AM, Richard Brekne wrote: > =A0 > > BobDavis88@aol.com wrote: > > =A0 > Hafta say I ain't buying this. The excursion of the string is so=20 > slight that I can't believe that an object 1/2" away could cause air=20= > to offer much impedance. I'm willing to bet if I held my thumb 1/2"=20 > from the string right above the strike point, no one could tell me=20 > when it was there and when it wasn't, blindfolded. > > Cant say I blame you. Does sound a bit fantastic.... to put it mildly.=20= > But next time you run into a grand that has obviously high checks you=20= > can try this out. > > Take any old note...maybe say A4 :), get a sense for its volume and=20 > compared with its neighbors. Run a few chromatics up and down. Then=20 > lower its back check to exactly 2 mm under the tail at drop and listen=20= > again. > > See what you think. I dunno, maybe you wont buy it then too. Maybe its=20= > like the proverbial green light at that last millisecond of sunset at=20= > sea..... But I do know what I heard. > > Sorry I don't have something more positive to offer as an explanation=20= > for optimal checking=3Dlouder tone. I'll be watching this space=20 > anxiously. > > Bob D > > =A0RicB > > -- > Richard Brekne > RPT, N.P.T.F. > UiB, Bergen, Norway > mailto:rbrekne@broadpark.no > http://home.broadpark.no/~rbrekne/ricmain.html > http://www.hf.uib.no/grieg/personer/cv_RB.html > =A0 > ---------------------- multipart/alternative attachment A non-text attachment was scrubbed... Name: not available Type: text/enriched Size: 2907 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/4f/3c/27/15/attachment.bin ---------------------- multipart/alternative attachment--
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