Unison Width

[Roger Jolly]

Nice post Ed.


At 06:05 AM 23/11/00 -0500, you wrote:
>Terry writes: 
>>I too, have tuned 
>quite a few "cheaper" or older uprights/grands, where it does indeed seem 
>that the margin for tuning a unison beatless, is RAZOR thin. <<
>
> Greetings,  
>     It seems that the most noticeable unisons are the ones that stick out.  
>If you have an octave or so of near-perfection going, with limpid, glowing, 
>resonant unisons,  and then come across a trichord that has a real riot 
>happening in one or more of its strings, it is going to stand out.  If, on 
>the other hand, every single one of those trichords is cursed with the false 
>beats,  a good tuning requires that they all howl the same.  
>     On request for a "honky tonk" sound, I once used a SAT to move one 
>string on all trichords above G4 up by 2 cents,(using the SAT for this keeps 
>a level of consistancy here so that intervals don't get too cloudy).  The 
>piano didn't really sound out of tune when played, (it sounded like there
was 
>signal processing going on).  Everybody soon got used to it.  I did get one 
>complaint about a dead note, and when I arrived, I found that the raised 
>string  had slipped, BACK INTO TUNE!  The clear unison stood out.   
>      A consistant out of tuneness stops being perceived as "out of tune".   
>I would also submit that this applies to harmony as well as unison, as 
>evidenced by so much acceptance of ET, which has everything "out of tune".  
>(Anyone ever talk about temperament around here? (:)}))
>      There are no absolutes, and the purest of pure unisons may not be the 
>most desired state,(see Weinreich). With this in mind, perhaps  the cheaper, 
>more tonally deficient pianos  require a wider margin to their unison width, 
>as in, don't make ANY of them pure, but rather, compromise them all so that 
>they sound the same.   
>     Width also doesn't completely describe what three strings are doing.  
>Width might be accurate for two strings, but the addition of the third means 
>that another level of complexity is in the signal.  Whereas two strings 
>describe a distance,(width), three describe a space.   The phase
manipulation 
>available to the tuner becomes  more extensive here, as moving one string
can 
>create several different relationships.  These differences create the sound 
>of the unison, and there is room to shape them on a good, clean piano.  
>Studio unisons, for me, occur most consistantly when I tune the outer
strings 
>to the SAT and let my ear settle the middle pitch down amongst the 
>"envelope".  This produces a pretty consistant sound through the
microphones, 
>and consistancy is what sells.  (Oops, I digress,  I think we started on 
>old/cheap pianos!)   
>   Ah well,  unisons can be a very deep subject, on levels both techical and 
>personal.  Unison between not only three vibrating wires but also among
those 
>of us fascinated by such arcane angels dancing.  Happy Thanksgiving to all. 
>Regards, 
>Ed Foote RPT 
>Nashville, Tn. 
>
> 
> 
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505