Joe, For me, this is awesome... thanks for posting it. I'll have to go through it a few more times while I "try this at home". Paul Bruesch Stillwater, MN On Sun, Jan 30, 2011 at 3:19 AM, Joe DeFazio <defaziomusic at verizon.net>wrote: > * > From: *Ron Nossaman <rnossaman at cox.net> > *Date: *January 29, 2011 10:54:52 PM EST > > On 1/29/2011 9:05 PM, John Formsma wrote: > > Someone on the list might have mentioned it. > > > Not that I've seen. I don't recall anyone - ever, in any situation, > mentioning testing unisons with intervals. This strikes me as weird, as > obvious is it is after the fact. Maybe if I'd had some actual instruction at > the start, it might have come up. I just sort of discovered the octave thing > by myself. > .... > Ron N > > > Hi Ron and John, > > I use 3rds and 6ths (and other intervals) frequently in tuning and testing > unisons, though not exactly in the way John does, if I follow John > correctly. > > I believe in a concept called "unison size," if I many coin a term (or > perhaps someone has already coined it). As is standard knowledge, the > various tests we all use rely on coincident partials, and unisons can be > tuned and/or checked using similar tests. Here's how I do it: > > Let's say you want to tune or check a unison on note C#3, and let's assume > for simplicity's sake that it happens to be a bichord. You could use A2 > below it forming a major third as your test note. > > Start by muting off all but one string of A2, and all but one string of > C#3. > > When you play A2 and C#3 together, the beating you hear is a coincident > partial at C#5 (a 5:4 coincidence), and it is the 4th partial of C#3 that is > participating in the beating. > > Listen to the beat rate, and then switch your mute to hear the other note > of the C#3 unison. If you tune the second C#3 string so that the beat rate > is exactly the same, or, if when you check the already-tuned other string > the beat rate is exactly the same, then you have an exact 4:4 unison. > > If you used A#3 as your test note instead, the coincident partial is F5 > (or, E#5, for us music theory nerds), and your coincidence is 5:4, with the > 5th partial of C#3 participating in the beating. So, if you match the beat > rates between the two strings of C#3 in this case, then you have tuned a 5:5 > unison. > > If you use E3 as your test note, you have a 6:5 coincidence, with the 6th > partial of C#3 participating, so you have a 6:6 unison, and so on.... > > --- > > If I read his post correctly, John is not referring to using mutes. > > If you don't use mutes and the unison is not good, then you will hear two > (or three) competing beat rates at the coincident partial, and that > blurriness in the sound (or lack of a clear beat rate at the coincidence, or > really a shifting maze of phase reinforcement and cancellation) is your clue > that the unison is not good. Thats why you don't like it. > > If you don't use mutes and the unison is good, then the beats at the > coincidence will reinforce each other (be in phase), and will be nice and > strong, which is your clue that the unison is good. Mmmmm good. > > So, really, the same principle of using coincident partials at a certain > unison size by using a test note is at work with or without mutes. "Without > mutes" is faster, of course, and "with mutes" gives you more feedback in > correcting the wayward string (i.e. - it tells you if it is too high or too > low, and by about how much as you compare the separate beat rates). > > --- > > I think that the "unison size" concept is most helpful in achieving > consistent tuning in pianos with lots of mismatched bichords. > > By ear and using tests as outlined above, find the unison size that sounds > the best to you (4:4? 5:5? 6:6? or even higher...), and then tune all of > your mismatched bichords to that same unison size. The bass can be more > consistent that way, even in those pianos with badly matched bichords. They > may all sound "wrong," but they will sound "the same wrong." Sometimes > consistency is the best you can do. > > As you choose the best sounding (least bad sounding?) unison size for the > mismatched bichords on a particular piano, I suggest that you listen to the > note by itself in evaluating the unison size, but then you should also > listen to the note in the context of P8s, M10s and P12s above, and perhaps > as the root of a major chord. Sometimes, the best sounding "solo" > and "harmonic" choices for unison sizes can be different, and you will have > to choose which to use. But, once you choose, I will once again suggest > that you use unison size tests to tune the other problem bichords > consistently. > > --- > > The "unison size" concept with mutes is also helpful many times with plain > wire strings that are giving you trouble in pulling in a unison. It can > even be used to tune high treble notes at more divergent coincidences, such > as 5:1 or 6:1 (with the "1" being the high treble note; you are tuning a > 1:1 unison, which is often the best choice in the high treble). At the very > least, it gives you feedback about whether a certain coincidence matches or > not. > > --- > > I would welcome other folk's ideas about unison size, such as: > > What unison size do you find works the best with mismatched bichords? > > What is more important, finding the unison size that sounds best solo or > the unison size that works best in harmonic context? > > And the like.... > > Joe DeFazio > Pittsburgh > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20110130/ba521d4b/attachment.htm>
This PTG archive page provided courtesy of Moy Piano Service, LLC