Dear Marcio and rest of the list, The effect is more obvious when using the log of the spectrum and a larger frequency resolution, as shown in the attached jpg. It shows the spectrum of the oboe playing the note G6 (1500 Hz) with peaks not only at multiples of 1500, but also at every multiple of 500. It was computed over the first third of the sample under discussion (oboe.pp.g6 from U of Iowa MIS). Attached is another example of a bass flute playing Bb4 (500 Hz), taken from the same set of samples. This time the subharmonics are not multiples of 1/3rd the pitch but one half, although they are present only below 1 kHz. Arturo > I have no knowledge about oboe, but I think the hypothesis from Dr Al > is very plausible. > > Listening to the sound file, after filtering it in 1/3 octave bands, > sometimes it sounds as the 500 Hz and 1000 Hz notes are played while trying > to reach the desired note. > > This could be related to the instrument's mechanism or to the player's > hability. > > I attached a spectrogram from the entire file (the "500 Hz" tone is > not present only in the first note) . > > Regards > > > -- > Marcio Henrique de Avelar Gomes, Dr.Eng. > http://www.ecoacustica.com.br > > -- __________________________________________________ Arturo Camacho PhD Candidate Computer and Information Science and Engineering University of Florida E-mail: acamacho@xxxxxxxxxxxx Web page: www.cise.ufl.edu/~acamacho __________________________________________________
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