Vocoder - 1000Hz Band

Do you know of the song "Let's Groove" by Earth, Wind & Fire? it has a heavily synthesized chorus that goes "The boogie sound, down up on down" over and over. Few people actually know what those lyrics say because the vocals are so distorted. And that is exactly what a Vocoder can do! Compress a voice signal to a varying degrees. The amplitude of several discrete frequency bands provided by a wide-band carrier signal are controlled by relative intensities of the corresponding frequencies present in the user's speech. Ideally, a vocoder would compress the signal while retaining intelligibility. Or... produce cool sound effects! This design only includes an implementation for the 1000Hz band (+- 150Hz) However, the other bands would just have different resistor and/capacitor values with identical layout. I've also included the files I used to simulate the circuit.