Fw: Electronic Sustain Timer

[Ned Swift]

Hi Sarah

Since you are considering Tune Lab, perhaps you might also consider using 
Power Tracks Pro Audio by PGMusic.  I use it in my recording studio for 
recording and editing music.  It has adjustable functions such as gates and 
limiters.  Gates cut off the low volume while limiters restrict the high 
volumes.  It will also allow you to measure the time of the sustain and you 
can look at the waveform.

The approach is quite simple. Record the piano on you laptop or PC. Process 
the recorded waveform according to your desired volume levels and then read 
the counter for the actual duration of the waveform.  You can even go in and 
look at the recorded waveform from start to finish or at any point that you 
choose.  Since the waveform is recorded, you can even create a library of 
sustains on various pianos.  The cost of the program is about $30.  For what 
it's worth.

Ned Swift
Lowell, MI






This isn't nearly as complicated as it sounds.
> >
> > No, it's much more complicated.  I know because I have done it in 
>TuneLab.
> >
> > If you look closely at the amplitude variations that occur as a note
> > decays, you will see that even if only one string is sounding, there is
> > still a beat-like variation due to the precession of the string from up
>0and
> > down motion to its ultimate elliptical orbit.  Any falseness in the 
>string
> > makes matters even worse.
>
>Your point is well taken, but my method actually takes that into account.
>(Perhaps I didn't make a big enough point of it in the original post.  I 
>did
>talk about it though.)  As both the upper and lower thresholds are
>crossed, the beating will cause the timer to switch in and out (or
>start/stop
>/start/stop or "stutter," if you will).  The final time reading will
>be a reflection of the total time spent between the threshold bounds.  If
>the beating is the same at the low amplitude (amplified 40 dB) as
>it is at higher amplitude, the jittering across the thresholds should have
>the same profile, and hence the demarcation of the "start" and "stop" times
>will "stutter" the same.  I don't know if I'm describing this clearly.  Am 
>I
>making sense?
>
>The circuit I propose is *really* easy and lends itself well to repeat
>measurements on many notes without time intensive calculations.  The method
>you propose probably also works well.  However, an electronic method of
>rectifying and averaging somewhat avoids the problem of the entry and exit
>of harmonic components as their vibrational components "rotate" randomly
>with respect to the fundamental.  Put another way, the peak profiles can
>have weird beating patterns of their own, even when the RMS value of the
>waveforms may be the same.  Of course only true RMS averaging would give us
>"the" answer, but simple averaging comes close.  Peak detection is the
>worst.
>I suspect this is a small point, though, and your method should work fine.
>Whatever works...
>
>I'll check out Tune Lab.  Thanks!
>
>Peace,
>Sarah
>
>
>
>_______________________________________________
>pianotech list info: https://www.moypiano.com/resources/#archives


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