Intense Tech #18 — ADSR Makes Life Easier! (Defense Mechanism)

defense-mechanism on the pulse/noise ADSR that lsdj 8.1.0 introduced and the switch from hardware to software volume in 8.8.0: how the stages are written, how the speeds compare, instant decays, percussion transients and an accidental tremolo (intense-tech).

Key claims#

• Old envelope / E command: first digit the initial volume 0–F; second digit 1–7 decreases (1 fastest, 7 slowest), 9–F increases (9 slowest, F fastest), 0 and 8 sustain indefinitely.
• ADSR (8.1.0): each stage "essentially acts as one E command" — first digit the volume, second the length of time to hold it; whether the volume rises or falls over that time "is specified by the next stage", and at the third stage it fades to zero. Examples: 54/00/-- starts at 5 and decays at speed 4 to silence; 03/A2/71 starts at 0, rises at speed 3 to A, falls at speed 2 to 7, fades at speed 1; 74/07/43 starts at 7, decays at 4 to 0, rises slowly at 7 to 4, fades at 3.
• Hardware volume before 8.8.0: "when hardware envelope is changed, the pulse or noise channel's sound is reset, which results in an audible click" (and a momentary tone change on noise), so stages could not blend. Since 8.8.0 software controls the volume: smooth changes, the table volume column no longer clicks, and K no longer clicks at the end of a note. E still works as before.
• Software speeds: 1 "extremely short", F "a bit longer than the previous speed 7"; best correspondence software → hardware: 0 → 0, 6 → 1, 8 → 2, 9 → 3, A → 4, B → 5, C → 6–7 — "five lengths that are faster than the fastest hardware envelope, and three that are longer"; length 0 always sustains.
• Instant decay: stage 2 or 3 with length 1.
• Transients: hi-hats at volume 6 quickly lowered to 4 and then fading cut through better than hi-hats fading from 4; a snare that needed E commands in a table under hardware volume (8.5.0) is done in the ADSR alone (8.9.6); at slow tempos such transients "can last less than a tick", impossible from a table.
• Emulator caveat: BGB has no software envelope in Game Boy mode — set it to Game Boy Color.
• Tremolo: because R can change the volume on each retrig, ADSR plus R gives a tremolo.

Practical takeaways#

Design pulse and noise drums in the ADSR, not in tables: a loud first stage with length 1–2 for the transient, then the body, then the fade. Anything written for LSDj 8.8.0 or later can assume click-free volume.

Notable quotes#

"Beginning with version 8.8.0, software has taken over control of the volume!"

Pages touched#

adsr-envelope · instrument-design · volume-slides · retrigger · lsdj · intense-tech · defense-mechanism