High-rate envelope information in many channels provides resistance to reduction of speech intelligibility produced by multi-channel fast-acting compression.

The intelligibility of speech in a competing-speech background was measured for signals that were subjected to multi-channel compression and then tone vocoded. The lowpass filter used to extract the envelopes in the vocoder preserved only low-rate envelope cues (E filter) or also preserved pitch-related cues (P filter). Intelligibility worsened with increasing number of compression channels and compression speed, but this effect was markedly reduced when the P filter was used and the number of vocoder channels was 16 as compared to 8. Thus, providing high-rate envelope cues in many channels provides resistance to the deleterious effects of fast compression.