Section 5: Cross-Overs, Moog VCF, Voice Synthesis, F0 Estimation, Cepstra, Converting to Minimum Phase

• Reading:
  • Review all assigned reading to date, slowing down where needed for full understanding

  • Supplementary:
    Linkwitz–Riley filter (aka ``Butterworth-squared filter'')
    Linkwitz-Riley Crossovers: A Primer
    Active Crossover Networks for Noncoincident Drivers in JAES Volume 24, Issue 1, pp. 2-8, February 1976

  • Supplementary: Spectral Envelopes via Cepstrum or LPC [from Music 421 overheads]

• Lecture Videos:
  • Voice Vowel Synthesis in Faust [11:26]
  • Moog VCF [23:29]
  • Moog VCF Live-Coded in Faust
    • Moog VCF Live-Coded in Faust [30:49]
    • Moog VCF in Faust, Review [5:02]
    • Moog VCF in Faust, Frequency Responses [7:39]
    • Supplementary: Q-Correction and Gain-Correction Tables [3:38]

  All remaining videos are supplementary, either moved beyond the scope of the class, or redundantly covering material already presented.

  • Voder [0:43]
  • Phonem for iPad by Wolfgang Palm

  • Minimum-Phase Spectra Play-List
    • Complex and Real Cepstrum, Quefrency [7:54]
    • Mel Frequency Cepstral Coefficients (MFCC); Bark and Equivalent Rectangular Bandwidth (ERB) Psychoacoustic Frequency Scales based on Critical Bands of hearing [7:54]
    • Complex Cepstrum Derived; Converting Mixed-Phase Signals to Minimum Phase [5:39]
    • Series Expansion of Log of 1/(1-x) [7:57]
    • Series Expansion of Log Transfer Function in Factored Form [5:26]
    • Contribution of Zeros to the Complex Cepstrum [3:15]
    • Contribution of Poles and Zeros (Inside and Outside the Unit Circle) to the Complex Cepstrum; Nonparametric Cepstral Folding Method for Converting Mixed Phase to Minumum Phase using the FFT; Testing for Time Aliasing [9:14]
    • Nonparametric Cepstral Folding Method in Matlab: minphasespec(), fold(), invfreqz() [6:11]
    • Review of another Cepstral Folding Example [19:08]
    • Minimum Phase Conversion by Spectral Factorization or Cepstral Method [5:45]
    • Minimum Phase Conversion by the Cepstral Method, Continued [12:10]
    • Cepstral Method Code, then CollideFX Demo by Chet Gnegy [55:51]