Vocoders

[Paul Perry]

THe definitive article:

"Vocoder Filter Design: Practical Considerations
Roger M Golden
The Journal of the Acoustical Society of America
vol 43, #4, 1968 p803-810

and might be useful:
Analysis of filter bank transfer functions
Milic, Kamsek, Jocic
IEE Proceedings, vol 134 Pt.G, #1, Feb 1987

these refs passed on from a friend who does this 
professionally (psychoacoustic processing for 
cochlea implants)

paul perry melbourne australia