AM/FM Modeling of Harmonic Sounds

Demonstration: thaiflute

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This demo shows, how the technique is capable of partially capturing the strongly breathy character of a blown instrument sound. This type of sound is particularly challenging for our model, since there is apparently a lot of narrowband noise around partials which is not reflected by common variations of IA and IF. Nevertheless, it is possible to re-synthesize a quite similar sound.

For a comparison, we show also the sounds reconstructed from the spectral modeling synthesis technique (SMS) by X.Serra. Please note, that while the SMS model is harmonic (in a sense that tracking is guided by the detected F0), it generates incoherent frequency trajectories that must be encoded individually. We also show a comparison with the bandwidth-enhanced sinusoidal model (LORIS) by K.Fitz which generates bandwidth-enhanced partials modulated by random noise. For fair comparison, we performed a partial selection operation ("distill" command of the LORIS software) that constraints the partials to harmonic multiples of the fundamental frequency.

Original sound (WAV file, 44.1kHz, 16bit, 370kB)

Reconstructed sound (WAV file, 44.1kHz, 16bit, 370kB) obtained from synthesis based on F0 + Harmonic Envelope subsampled 1:1000
(A phase incoherent, baseline heterodyne analysis, acting as a mock-up of a perfect harmonic sinusoidal model, without residual noise)

Reconstructed sound (WAV file, 44.1kHz, 16bit, 370kB) obtained from synthesis based on instantaneous F0 + Harmonic Envelope subsampled 1:1000 + prototype signal. NOTE: no residual noise is modeled in this example.

Reconstructed sound (WAV file, 44.1kHz, 16bit, 370kB) obtained from synthesis based on F0 + Harmonic Envelope subsampled 1:1000 + a noise residual modeled by 10-th order WLPC.

Reconstructed sound (WAV file, 44.1kHz, 16bit, 370kB) obtained from synthesis based on instantaneous F0 + Harmonic Envelope subsampled 1:1000 + prototype signal. As above, the noise residual is modeled by 10-th order WLPC.

Reconstructed sound (WAV file, 44.1kHz, 16bit, 395kB) obtained from the SMS technique with frame rate 44Hz (hop = 1000 samples) and no residual noise. Please note the chaotic frequency variations of high-order partials which is caused by estimation problems at low SNR and tracking errors. The audible effect of these variations is reflected by the "warbling" sound.

Reconstructed sound (WAV file, 44.1kHz, 16bit, 370kB) obtained from the SMS technique (as above) + background noise modeled using 10-order WLPC. We used our own noise model in this example, since the traditional LPC-based model in the SMS software produced too much artifacts. Note that the artifacts are not masked by the noise.

Reconstructed sound (WAV file, 44.1kHz, 16bit, 370kB) obtained from the LORIS technique bandwidth association region width of 500Hz and partials constrained to harmonic. Unfortunately, the harmonic restriction leads to very audible artifacts. The amount of noise is sometimes over-estimated. If you know, how to obtain a better result for this sound, please tell us.

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