I concur, I've tried using these latest ETD, some very sophisticated, but what your describing is one of reasons I don't use them. Another annoying feature is the millisecond delay in response. Surprisingly, I found the strobe tuners don't have that delay (it's analog) and the "jumping around" as you describe isn't present. The two frequencies are clearly shown and the jumping around is averaged out through the analog input (via flashing strobe) against the spinning wheel.
Original Message:
Sent: 01-14-2024 13:03
From: Peter Grey
Subject: False Beats: Two Origins: Acoustic vs Mechanical
One of my objections about ETD's over the years has been in fact this issue of how the thing "handles" false beats. Granted, I have not tried every ETD available, however the ones I have used (Accutuner, Tunelab, Pianometer, and possibly another that I can't think of) all jump around with varying degrees of incomprehensible indications that tell me they are in fact registering these false beats and trying to make sense out of them. My response to that has been: "Why am I wasting my time staring at this thing that is not smart enough to get past what my ears already tell me abd I have learned to mitigate in an analog/aural manner?" Thus I shut the thing off and go about doing what I know how to do.
It is possible that this device can help me overcome this digital limitation.
Peter Grey Piano Doctor
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Peter Grey
Stratham NH
(603) 686-2395
pianodoctor57@gmail.com
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Original Message:
Sent: 01-14-2024 12:03
From: Bill Ballard
Subject: False Beats: Two Origins: Acoustic vs Mechanical
Steve went: The point was NOT about the ETD, but the sensing of the false beat. Did you miss that point?
Not at all, your point was made well before this video: your sensor is the best set of ears and ETD could have. By the time a mic has picked up the sound pressure vibration from the air molecules, we're only getting a 2d or 3d-hand version of what's actually happening at the string.
It just happened that at the point in this multi-topic discussion where the matter of false beats came up, I thought I'd suggest something which occurred to me years ago: ETDs simply do not include false beats in the sampling for the FFT. I would love a thumbs up or down on that idea.
The thing I was unsure of from the video was your description of how ETDs actually do include false beats (again an AM-modulation artifact in a process where FFT is sorting out frequencies). You make it sound as though when a false beat exists, 1.) the ETD assumes that it's there because two very close frequencies exist to produce the beat rate, and 2.) it resolves this perceived clash of frequencies by replacing them with a frequency somewhere in between them.
I don't doubt that with your background, you could surmise how an mic-fed ETD might be interpreting a false beat, while for the rest of us this is just a black box. But your assumption of the ETD programmers' approach to false beats (as show in the video) does not credit them with much sophistication. I'd really be surprised to find that all of their approaches to false beats are as slap-dash as you portray.
Again, I stand by my belief that ETDs don't pay attention to false beats occurring octaves below the note they are seeking to define.
Also, anyone is free to chime in about how to determine whether a false beat's source is acoustic or mechanical. It's common knowledge. And as for mechanically-generated false beats, if there were 2-3 treatments which could work for all cases, false beats wouldn't show up in piano tech forums.
Also, there's a matter of how precise our tunings need to be, given that they're intended for human ears. Tap water in a glass looks clear until we put it under a microscope. But then we drink it and enjoy it.
All the best,
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William Ballard RPT
WBPS
Saxtons River VT
802-869-9107
"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The Continental Harmony,1774
Original Message:
Sent: 01-13-2024 22:31
From: Steven Norsworthy
Subject: False Beats: Two Origins: Acoustic vs Mechanical
The point of the video was to show that the source of the false beat is important to know. If it is mechanical and origin, you might be able to do something about it at the bridge pins, and this is a well-known technique of sophisticated tuners. If it is acoustic in origin, then there's nothing you need to do to the string at the bridge pins. That was the point of the video. You cannot find this in the literature, as far as I know, that there are two sources of false beats: acoustic vs mechanical. If we know the source of the false beat, we have a better shot of doing some thing about it. I am still 'yet' to receive a direct comment on the video. The point was NOT about the ETD, but the sensing of the false beat. Did you miss that point? I hoped the video made it clear. NO ETD was used in this analysis. But an ETD, any of them, will benefit from the sensor because it will not 'hear' the acoustic false beat. I hoped that was clear but maybe it wasn't. I do kindly thank you for watching it.
Best,
Steve
Original Message:
Sent: 1/13/2024 9:00:00 PM
From: Bill Ballard
Subject: RE: False Beats: Two Origins: Acoustic vs Mechanical
Peter Grey went:
(…snip) And anyway, we all know that we can overpower some of these "false" beats with careful unison tuning, and they "magically" disappear.
Actually, I believe that any ETD will have a definite advantage over our own ears. A false beats (in the beats/sec range that we can hear) are actually an AM-modulation of the the sound coming off that string. If we're tuning A6 aurally, and if there's a 5 b/s false beat, we hear both that and the 1772 Hz fundamental. If the ETD is doing the tuning, then at that point in the tuning pattern, it's only paying attention to something in the neighborhood of 1771 Hz (± 50 Hz). For it, the 5 b/s false beat is well off its radar.
And yes, false beats are annoying during aural unison tuning. If only one of the strings on that note is false bearing, we're in luck. We simply tune those two non-beating unisons to themselves, and, that done, tune the false beater working with only the beat rate which is moving. This is tricky because both the moving and stationary beats are in the same range and can be confused. But in the end, you'll know the unison is done because 1.) the only beat to be heard is the false one, and 2.) the complete amplitude of the false beat has been reduced reduced from 100% (when listening only to the false beating string) to 33% (when that string is added to its non-beating partners). So, while we don't pay attention to the false beater's reaction to our tuning of it, it's good to recognize that beat rate when it shows up as the only imperfection in our final unison.
Things aren't that much more complicated when there is only one non-beater in that trichord. You tune each beater, separately, to the non-beater, and in the addition of sound waves, the sum of these AM-modulated beats will still amount to only 1/3 of the volume. (…except where both beaters have the identical beat speeds, in which case they will reinforce each other and overpower the non-beater's volume.)
And when all three strings are beaters, that's when you thank the existence of ETDs.
But still, we should recognize that while EDTs can ignore beat rates, their best work will still be no different from our best aural work. If we're bothered by traces of false beats in the final tuning, they will be there no matter if tuned by ear or ETD. ETDs have no better chance of making a false beat disappear than a skilled aural tuner. ------------------------------
William Ballard RPT
WBPS
Saxtons River VT
802-869-9107
"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The Continental Harmony,1774
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