DSP II: Final presentation Vocoder - making music talk

DSP II: Final presentationVocoder - making music talk Van Damme Wim Hemeryck Martijn

Overview • Summary LPC vocoder theory • LPC vocoder demonstration • Channel vocoder theory • Channel vocoder demonstration

Summary LPC vocoder theory Encoder Decoder

Segmentation • Use of a window function: hanning • Without window overlap: not very smooth sound, many glitches • With window overlap: slightly smoother, but sometimes messy pitch and intonation

V/U/S detector • Goal was the lpc-10e standard: weighted voicing detection using several indicators → too little information, well hidden Tremain paper • In the end: a fairly simple speaker independent (normalized!) voicing detector using MSF, ZCR and pitch information

Demonstration LPC • No window overlap • High pitch (female) • Low pitch (male) • Window overlap • High pitch (female) • Low pitch (male) • Own voice → more noise

LPC vocoder and music • Basic idea: replace pulse train for voiced frames with periodic elementary note shapes of a music instrument, at a frequency corresponding to the pitch. • No access to such libraries • Therefore: channel vocoder…

Channel Vocoder theory

Channel vocoder demonstration • Example • ‘Around the world’ • Real-Time

DSP II: Final presentation Vocoder - making music talk