808 Maracas Synthesis
The 808 uses a short burst of high-passed white noise to create an highly artificial and unrealistic emulation a shaker/maraca. It sounds like a soft fuzzy “chik.”
A more realistic maraca would be built out of 2 sounds like the open and closed hat.
Main Components:
• White Noise
• VCA: Q65
• An Envelope: Q66 and Q67
• High-pass Filter: Q68
• Buffer: Level/Accent/amplification: IC19
1: White Noise
Use white noise as the sound source.
2: VCA & ENV
Pass the white noise through a VCA, then modulated it with a short envelope. Unlike other 808 sounds the Maracas has an AR envelope rather than a decay only envelope.
The overall sound is between 25 and 35ms. The Maraca is the second shortest sound on the 808 (the rimshot is the shortest). Compare the maraca and conga waveforms above. The conga has a decay only envelope with an immediate attack and a longer gradual decay. The maraca has a shorter waveform, but it has an attack/release shape with a rise time approximately 3/4 of its overall time.
3: High-Pass Filter
Remove the low frequencies with a high-pass filter.
You can switch the order of steps 2 and 3. The 808 circuit goes: Noise>VCA>Filter. But you can go: Noise>Filter>VCA.
4: Output Amplification
The filtered sound is sent to a buffer, which amplifies the sound, sets velocity, and accent level.
Further Reading
Pg. 6 has a brief description of the combined clap/maracas circuit (CP/MA).
Pg. 7 has a block diagram (top right, under the SD).
Pg. 9 has the circuit diagram (bottom right).
Pg. 14 has a chart displaying the decay time (M).