[pianotech] A demo of oscillation interactions

[Ron Nossaman]

On 9/27/2012 11:39 AM, Cy Shuster wrote:
> For those of us dealing in the interactions of vibration over time, this
> is pretty fascinating! 32 metronomes start randomly, and then
> synchronize. Watch the right-hand row around the 2:00 mark for an
> antinode to develop, and notice how quickly it shifts phase. The
> platform the metronomes stand on appears to be suspended by string, and
> the amount it moves left and right changes a lot over time.

This very thing happens tuning unisons too - probably everything else as 
well, but it's more obvious with unisons. The yeooowwwwwwww heard as two 
strings come close together in tune is the two of them drawing together 
  and synchronizing courtesy of the moving common termination at the 
bridge. Interestingly, farther apart in tuning and you'll get a beat, 
but at a certain point, you'll get the yeow on attack that never repeats 
as a slow beat. This is why I've said for so long that pretty much 
everything important to tuning happens in the first half second of the 
attack. That's aural tuning, because that's what I do. I've listened to 
people tune unisons, listening three or four seconds into it waiting for 
the next beat, then moving on when it doesn't come, leaving the yeow in 
the attack and a less clean unison than they intended. If the metronomes 
were set at significantly different periods (through a broader range), 
they would cycle in a periodic pattern.

Neat stuff.
Ron N