Cyber ears

[Richard Brekne]

Robert Scott wrote:

> Several suggestions have been made for an electronic tuning aid that
> displays beat information only, without any regard to an assumed
> tuning curve.  Speaking as one who has written ETD software, I would
> like to address this issue.
>
> All major ETDs display beat information between a single note and
> an internally generated reference signal.  Furthermore, all major
> ETDs display information on only one partial at a time.  Steve
> Fairchild has suggested tuning while considering two or more
> partials at a time and has even constructed some experiements
> using several SATs at once (set to different partials).  But
> the comparisons are always between a single note and an
> electronically synthesized reference.
>
> What is different about the present proposals is that the ETD
> not use any internal reference.  Instead the technician would
> strike two keys at once, just as in aural interval tuning,
> and let the ETD "listen" to the beats between the two
> different notes and display the results in some manner.
>
> IMHO, this ETD would be significantly harder to make than the
> current ETDs.  What you find fairly easy - picking out beats
> between two simultaneously sounding notes - actually relies
> on the incredibly complex pattern recognition capabilities on
> the ear-brain combination.  There are amplitude fluctuations
> across the frequency spectrum.  Yet to hear beats, you have
> to be able to pay attention to amplitude fluctuations at
> only one frequency, ignoring all the rest.
>
> There is a similar problem in radio communication with
> Morse code.  Like beats, Morse code is made up of
> amplitude variations.  Within the crowded amateur radio
> bands you may find a number of stations so close together
> in frequency that the radio is incapable of separating
> them.  But a highly skilled amateur radio operator can
> pick out and understand a single transmission admidst
> all the interference.  When computers came along, it was
> natural to try to make a computer read Morse code.  This
> effort has been met with limited success.  Computers can
> read Morse code, but only when it is fairly clear.
> Under the most difficult situations, the human listener
> still copies Morse code better than the computer.
>
> If an electronic device can detect beats, it would only
> be in situations where the beats were easy to hear
> anyway.  As beats get harder to hear, the electronic
> device will fail sooner than the human ear.
>
> -Robert Scott
>  Real-Time Specialties

All this is true as you state, But if the machine was to set to the job
of listning to the partials of each of the two notes, and then
calculateing the difference between all coincedentals, would this not be
an approach which would work. I am not suggesting that a computer should
"hear" the beats as the human ear does. Rather exploit the number
crunching capability of a computer.

We hear beating between two notes, and try to estimate the beat rate as
you say based on the amplitude or shall I say "hearability" of the
beating, and its real speed. Excellent tuners are amazing in this
regard. Trying to emulate this capability humans have directly in a
computer does sound like a tough one.

But the computer can sample to notes, and all relavant partials. Compare
the frequences of coincidents and calculate the difference, and finally
present the resulting data in terms of bbs.

Does this sound do-able ?

Richard Brekne