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PSaHMICASSP

PITCH MODIFICATIONS OF SPEECH BASED ON AN ADAPTIVE HARMONIC MODEL

George P. Kafentzis, Gilles Degottex, Olivier Rosec, and Yannis Stylianou

Abstract - In this paper, a simple method for pitch-scale modifications of speech based on a recently suggested model for AM-FM decomposition of speech signals, is presented. This model is referred to as the adaptive Harmonic Model (aHM). The aHM models speech as a sum of harmonically related sinusoids that can adapt to the local characteristics of the signal. It was shown that this model provides high quality reconstruction of speech and thus, it can also provide high quality pitch-scale modifications. For the latter, the amplitude envelope is estimated using the Discrete All-Pole (DAP) method, and the phase envelope estimation is performed by utilizing the concept of relative phase. Formal listening tests on a database of several languages show that the synthetic pitch-scaled waveforms are natural and free of some common artefacts encountered in other state-ofthe- art models, such as HNM and STRAIGHT.

Thank you for your time !

In this test, the goal is to evaluate the perceptual quality between recordings of speech and their pitch-scaled reconstruction by several algorithms and for several pitch-scale factors.

You will listen several artificially pitch-scaled speech waveforms. The time scale factor varies from 0.5 to 2. The criteria of quality include artifact-free waveforms, such as chorusing, buzziness, whispering, metallic/robotic voice, etc, and naturalness.

At first, you will play the original sound as many times as you want (labeled Original). Then, you will play the other sounds as many times as you want again, and select which one pitch-scaled speech signal has the highest quality. The original signal is given as a reference.

Recommendations

• If there is any technical problem with one sound, select Prob.
• Absolutely use headphones. Do not use earphones or speakers.
• Verify that the sound is loud enough to hear the details properly.
• Do the test in a quiet place.
• Take the time to listen !
• Please, do not stop the sound before it finishes!
• Please, do not play audio files simultaneously !
• Before answering the test, do not hesitate to ask me any question.

The following pitch scaling modifications have a factor of 0.5 to 2, respectively.

The test

Please, select the sound that is more naturally pitch-scaled according to the Original.

THANK YOU!