Author: mschmidt
Date: 2010-09-11 03:02
Ultimately, it is the distribution of overtones that determines the timbre. Traditionally, more amplitude in the fundamental frequency and less in the overtones was what "dark" meant. In the past, I had made some investigations of the relative strength of fundamental and overtones with some freeware Fourier transfer utilities (usually called Spectrum Analyzers) but a lot of these analyze "on the fly" and so it's hard to note subtle differences. Recently, after reading some posts in the Clarinet BBoard, I have investigated other tools that can analyze many seconds worth of recorded sound, resulting in an average sound spectrum which really does correlate with the traditional picture.
Playing my old Marigaux and newer Lorée in the lower-to-mid range, I (and others) would say that the Marigaux is darker. The Fourier transforms show that, for A440, both instruments have strong signals for 220, 440, 660, and 880. 660, the third harmonic of 220, is actually the strongest signal for both instruments! The differences between the two oboes are greatest above 1100 (the 5th harmonic of 220). 1320, the sixth harmonic of 220 (and the 3rd harmonic of 440) is much bigger for the Lorée, as is the 11th of 220 (2420 Hz). The Marigaux is a little bit bigger for the 8th and 9th harmonic of 220, but neither of these is as big as the 6th and 11th in the Lorée. So yes, the "brighter" instrument does have more upper harmonics--but only very particular ones!
And things change in other ranges. I like the Loree better in the upper range--it sounds more "covered" in the region of the second octave key than the Marigaux. Well, if you look at the spectra for A880, you find that the Lorée favors the fundamental over the upper harmonics for this note--it's "darker!" At A880 on the Lorée, the signal at 880 Hz is the winner, 440 is strong, and then there are just three tiny peaks for the 3rd, 4th and 5th harmonics of 440.
By contrast, the Marigaux's highest signal is for 440 by a lot, and the 3rd and 4th of 440 aren't too tiny. The fundamental loses out to the odd harmonics in the upper range of the Marigaux.
If I figure out how to get the spectrum pictures off the program (AudioXplorer for Mac OSX) I will try and get them posted somewhere where you can see them.
Mike
Still an Amateur, but not really middle-aged anymore
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The Oboe BBoard
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