Hi, Consider also that strings of a unison are already coupled by the bridge pins agraffe etc. ----- Original Message ----- From: "Ed Sutton" <ed440 at mindspring.com> To: <caut at ptg.org>; "Kent Swafford" <kswafford at gmail.com> Sent: Wednesday, June 10, 2009 7:47 PM Subject: Re: [CAUT] String Coupling / SB and Bridge stiffness...and maybePure Sound > Kent Swafford, are you there? > > Consider this line of thought: > > Assuming that all unisons involve some degree of coupling, then it is not > possible to tune a "mathematically perfect" unison by usual aural methods > because, as the tuned note approaches unison, when it passes the "coupling > threshold" it will couple with the other string(s) without having to be > the exact matching frequency. (Listening high up the partials would help.) > > Since, with Tunic Pure Sound, you are tuning each string of the unison > "solitary," to match the ETD display, is it possible that the three > strings, when tuned this way, are closer to a "mathematically perfect" > unison that an aurally tuned unison can be? > > Can this account for the unusually clear sound of certain very widely > spaced chords on the Hailun piano you tuned with Tunic? > > Ed Sutton > > > ----- Original Message ----- > From: "Andrew Anderson" <andrew at andersonmusic.com> > To: "College and University Technicians" <caut at ptg.org> > Sent: Wednesday, June 10, 2009 9:27 PM > Subject: Re: [CAUT] String Coupling / SB and Bridge stiffness > > >>I have seen a demonstration of coupling strings with a staple-like device >>in order to tame excessive false beating. It was interesting how far >>out-of-tune with each other they could be before you would hear a beat. >>The coupling done in this fashion weakens the higher partials and so in >>the plain wires is usually utilized only on two strings of a unison. In >>the bass weakening the the higher partials would be a blessing on some >>the of cheap Asian "pianos" I've tuned. >> >> I do like the Sauter treble, I have an Omega here at the store and it >> also has titanium pins etc. Strong, well balanced trebles, do seem to >> be the hallmark of all the Sauters that have passed through this store. >> >> Andrew Anderson >> >> On Jun 10, 2009, at 4:57 PM, Ed Sutton wrote: >> >>> If you can hear the string, it's fair to assume the soundboard is >>> moving at frequencies similar to some of those in the string, therefore >>> it's reasonable to assume that the bridge is also moving. Thus it is >>> also likely that when frequencies are very close, coupling will occur. >>> The amplitude of the wave in the string will play a role as well. >>> Perhaps when it becomes too small to move the bridge, the strings >>> de-couple, at least at that particular partial. >>> >>> This may not involve all the partials of the unison at all times. For >>> example, in the higher octaves the first partial may become inaudible >>> almost immediately. The Sauter concert grand with titanium armor in the >>> top octaves is remarkable for the clarity and sustain of the first >>> partials in octaves 6 and 7. >>> >>> Ed S. >>> >>> >>> ----- Original Message ----- From: "Richard Brekne" >>> <ricb at pianostemmer.no >>> > >>> To: <caut at ptg.org> >>> Sent: Wednesday, June 10, 2009 6:01 PM >>> Subject: Re: [CAUT] String Coupling / SB and Bridge stiffness >>> >>> >>>> Hi... no bites on this so I thought I might try phrasing it a >>>> different way and see if I could get any feedback. >>>> If the string terminations were infinitely stiff, then there would be >>>> no mechanism for string coupling .... yes ? You could in theory have a >>>> piano unison, excite the strings in the usual way with the hammer.... >>>> but the infinite stiff terminations would not allow for any coupling, >>>> there by the strings would each vibrate completely independent of one >>>> another. Ok.... so add a set of non infinitely stiff bridge pins and >>>> leave everything else about the terminations infinitely stiff. You >>>> still have the same situation, tho the bridge pins become some form or >>>> another of an extension of the string. Perhaps this scenario would >>>> open for false beats on individual strings at best, but there is still >>>> no mechanism for the three strings to couple given the infinite >>>> resistance to vibration by the bridge itself. So no pitch drop due to >>>> coupling is possible as no coupling is possible to begin with. Yes >>>> ??... So at some point the bridge becomes non-stiff enough to allow >>>> for this coupling. And the more non-stiff the bridges becomes... the >>>> greater the ability for the strings to couple, hence the greater their >>>> influence on each other... and hence the more evident (greater degree >>>> ?) of pitch drop.... Or what ? >>>> >>>> Cheers >>>> RicB >>>> >>>> Got to thinking abit about string coupling and the mechanisms that >>>> are at work that account for the pitch drop and got to wondering if >>>> it is viable to think of the degree of pitch drop when 2 and 3 >>>> strings are coupled in on a unison as an indicator of SB/bridge >>>> stiffness at any given note. >>>> >>>> Or... is this another one of my rabbit holes ? >>>> >>>> Cheers >>>> RicB >>>> >>> >> >
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