Re: voiced/unvoiced detection ("Alain de Cheveigne'" )

Subject: Re: voiced/unvoiced detection
From:    "Alain de Cheveigne'"  <alain(at)LINGUIST.JUSSIEU.FR>
Date:    Wed, 11 Nov 1998 10:14:16 +0100

Pierre Divenyi <pdivenyi(at)MARVA4.NCSC.MED.VA.GOV> wrote: >That is, if I were able to >whisper louder than the highway noise, I could be perfectly intelligible >speaking in a car with the windows down, despite the fact that the >autocorrelation of the speech I am producing would be absolutely flat. Not absolutely flat. If the excitation is white noise, the autocorrelation function (of the waveform) should look like the impulse response of the vocal tract. No period peaks to be sure, but not flat either! Another way to put it is to say that ACF and squared magnitude of the vocal tract transfer function are Fourier Transform pairs. Features in one translate to dual features in the other. For whispered speech, one should probably distinguish the issues of transmitting segmental information ("phoneme" identity, etc.), and intonation. To the extent that segmental information is carried by spectral shape, it is coded equally well if the excitation is noise-like. A speech recognizer trained on voiced speech should work on whispered speech. In principle. In practice there are issues such as the different spectral slopes of voiced and whispered excitation, and the fact that speakers might not articulate the same when they whisper as when they use voice. Intonation is another problem, as it is usually thought of as being coded by F0 which is absent in whispered speech. I think it has been suggested that F1 might be used in the place of F0 (how to reconcile this role with that of coding segmental information is another mystery). Other parameters are timing and intensity. Introspection tells me that whispered articulation is more marked than voiced articulation, something akin to a sort of "Lombard effect". It may be a mistake to equate "whispered speech" with "voiced speech minus the F0". Alain Email to AUDITORY should now be sent to AUDITORY(at) LISTSERV commands should be sent to listserv(at) Information is available on the WEB at

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