Dear List,
While we're on the subject of musical pitch tuning and tracking, since
this is a subject I've been interested in for a long time, I would like
to put in my 2 cents (maybe more).
Musical pitch tracking is an old subject. Seashore published some in
1932 and Obata and Kobayashi in 1937 and 1938. Tove et al. described
a system consisting of transistor electronics and a fast chart
recorder in 1966. The idea is to plot melodies graphically to see
what kinds of pitch and rhythmic changes occur over a substantial
duration. As Tove et al. said,
"The need for objective notation of time variations of frequency and
amplitude in theoretical studies of musical phenomena is obvious and
should have many applications in investigations of style, rythm (sic),
and variations and deviations of key, in the study of conventional,
modern, and folk music, as well as in basic studies of musical
perception and creation."
InterOcean Systems developed and marketed a real-time music analyzer
called the Melograph in the 1970s, based on research by Charles
Seeger at UCLA. It was contained in a compact rack-mounted package
with an internal chart recorder and sold for about $8000.
Unfortunately I couldn't afford to buy one.
Since the advent of the computer, a plethora of pitch detectors/ trackers
have been developed, and there's been too many to mention all of them.
In 1989 at our lab at Univ. of Illinois at Urbana-Champaign, Rob Maher
developed a nice one for music based on the short-time Fourier transform
and a method called the "two-way mismatch (TWM) method", as part of his
PhD thesis on musical sound source separation. This non-real-time program
is contained in the SNDAN suite of programs that is available for free
download and compilation on Unix systems (e.g., Linux or Mac OS X). A
Windows/DOS version is also available. (See
http://ems.music.uiuc.edu/beaucham/software/sndan/ ) This method also
generates a chart-recorder-like image of musical pitch vs. time.
Recently Ugar Guney developed a real-time version of the TWM method,
which again is a free download and is platform independent if you
have Java installed, called "freqazoid". This is definitely in beta form,
but, again, it's free.
I've also used the autocorrelation pitch detector in Praat and, after
converting the frequency output to log form and graphing, have gotten
similar results. This is also a free download.
What is needed is a system that is accurate to a few cents but can also
cover a wide range of pitch, at least 3 octaves, but 7 would be great.
It should be able to handle a wide variety of waveforms, drop outs, a
fair amount of noise and inharmonicity, and it should be able to handle
very fast changes in pitch, i.e., it should be able to accurately
transcribe virtuosic passages (64th notes, etc.), as well as glides,
vibrato, and portamento.
Besides displaying the data on a log(f0) vs. time chart, the system
should also be able to generate the data to a file for subsequent
post-processing research. Conversion to MIDI and musical notation are
nice features, but these are already available in programs once the
log(f) data is provided.
I see that G-tune, which has now merged with Peterson Electro-Musical
Products, has morphed into StroboSoft 2.0. This contains a vast number
of tuning features, but the feature that I'm most interested in is
its "pitch graph", which is only provided in the deluxe version ($100).
Unfortunately, they don't spec the accuracy, range, and speed of this
graphing tool.
I would also like to mention that our group is also interested in
polyphonic pitch detection, i.e., simultaneous pitch transcription of
more than one voice at a time. Some progress in this field has been
made during the last few years. Recently Anssi Klapuri and Tuomas
Virtanen have made a good summary of these efforts (see below).
Jim Beauchamp
Univ. of Illinois at Urbana-Champaign
References
Seashore, C. E., "The Vibrato", in Studies in the Pschology of Music,
Vol. 1, U. of Iowa (1932).
Obata, J. and R. Kobayashi, "A Direct Reading Pitch Recorder and its
Applications to Music and Speech", J.A.S.A. Vol 9 (1937).
Obata, J. and R. Kobayahsi, "An Apparatus for Direct Recording the
Pitch and Intensity of Sound", J.A.S.A. Vol 10 (1938).
Seeger, J., "Toward a universal music sound-writing for musicology",
Int. Folk Music Council, Vol. 9 (1957).
Tove., P. A., B. Norman, L. Isaksson, and J. Czekajewski, "Direct-
Recording Frequency and Amplitude Meter for Analyzing of Musical and
Other Sonic Waveforms", J. A. S. A. Vol. 39 (1966).
Boersma, P., "Accurate short-term analysis of the fundamental frequency
and the harmonics-to-noise ratio of a sampled sounds", Proc. Inst.
Phonetic Sciences, Vol 17, Amsterdam (1993).
Maher, R. C. and J. W. Beauchamp, "Fundamental frequency estimation of
musical signals using a Two-Way Mismatch procedures", J. A. S. A.,
Vol. 95 (1994).
Klapuri, A. and T. Virtanen, "Automatic Music Transcription", Handbook
of Signal Processing in Acoustics, Vol. 1, Springer (2008).