Bell Labs 1930s tests found three channels sufficed to transmit a soundstage
Evidence
Speech coding methods thus use the principle behind the vocoder (short for voice encoder), which was developed in the 1930s (Dudley, 1940). In the original implementation, the input speech signal was passed through a filter bank, and the signal in each band was passed through an envelope follower. The control signals from the envelope followers was communicated to the decoder. The decoder applied these (amplitude) control signals to corresponding filters in the synthesizer. Since the control signals changed only slowly compared to the original speech waveform, the bandwidth required to transmit speech was reduced, and the parameters could be modelled statistically. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2225 (
#complicates, via linked claim)
Categorization
- XREF: connects to: Bell Labs recognized multichannel benefits as early as 1934; The 1930s vocoder pioneered reducing speech to slowly-varying parameters to cut bandwidth — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2225
Broader Connections
- The 1930s vocoder pioneered reducing speech to slowly-varying parameters to cut bandwidth
#complicates(0.75) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2225