HI Robert, That window exists because current edt's tune only one partial, generally speaking the partials on any 2 wires do not line up perfectly. My own belief is that our ears hear the *noisiest* coincident partial when doing unisons, and then we juggle it by ear until we have a cancellation effect. One could experiment by tuning various partials--but an edt is supposed to save time not take more time. I also believe that the pitch *change* (not necessarily a drop from my puny research) is partly due to the imperfections in the wire, becuase while f6 may *drop* in pitch f#6 may be *sharp* of pitch after unisons are tuned. At 08:26 PM 2/14/01 -0700, you wrote: >Hi Roger >I'm really on a roll tonight , this is my 3rd reply.Correct me if I'm wrong >,but are you saying that you tune each string a number of times with the >RCT,then take a reading of the three together and have a pitch drop of .3 >cents.I have been using a Sat for a number of year sand I find that I cannot >always use the lights to tune a unison.I do not have a RCT to do a real >comparison but I find that when the lights stop there still is a "window '' >to tune within.With my SAT a difference of .3 cents would be noticable to >the ear.I would wonder if all that has happened is that one of the strings >is not in unison. >Regards >Murray >----- Original Message ----- >From: "jolly roger" <baldyam@sk.sympatico.ca> >To: <pianotech@ptg.org> >Sent: Wednesday, February 14, 2001 9:27 AM >Subject: Re: ETD question re: unisons > > >> Hi Howard, >> Yes it is easy to confirm. The test that I have done >with >> a RCT show about a 0.3 cent drop in octave 5/6. The test was performed by >> tuning each string individually several times, to over come the >> interaction. then the net 3 string unison was measured. >> The effect is known as string coupling. >> My own theory is that. as all strings start to increase the amount of >> energy into the bridge, the board is moving through a greater excussion, >> and hence dropping the frequency a tad. >> Now I've been out to lunch before, and I could be off base on this one. >> Regards Roger >> >> >> At 10:47 AM 2/14/01 -0500, you wrote: >> >Hi everyone, >> > >> >Since I know nothing about ETD's my question might be naive. Nevertheless >> >here goes: I believe that Virgil's assertion that a 3 string unison is >> >flatter than each of the single strings heard singly, is a bit >questionable >> >or should I say not fully accepted. Wouldn't it be easy and conclusive to >> >check this thesis by using an ETD to measure this? Thanks! >> > >> > >> >Howard S. Rosen, RPT >> >7262 Angel Falls Ct. >> >Boynton Beach, Fl 33437 >> > >> >hsrosen@gate.net >> > >> >> > > > Regards, Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T. Tuner for the Saskatchewan Centre of the Arts mailto:drose@dlcwest.com http://donrose.xoasis.com/ 3004 Grant Rd. REGINA, SK S4S 5G7 306-352-3620 or 1-888-29t-uner
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