ROCK ROTARY — signal-flow flowchart

Image rep algo 15 · slots 15,53 · unit 0 (I-RAM load 84) · family rotary · confidence high.

rock rotary / rotary speaker (shared with algo 53)

86 words, 33 class-A coefficient multiplies (6 named), 0 instructions still opaque, 19 of 86 not yet decoded. Landmarks detected: 1 biquad DF-I section(s), 5 C-format immediate load(s), 1 DRAM read/write word(s), 1 waveshaper LUT selector(s), 2 class-8 post-sum step(s).

flowchart TD
    N0["Stereo input (L / R)"]
    N1["External delay line (DRAM)<br/>1 read/write word(s) (880.1.60 = READ, 880.1.20 = WRITE)"]
    N0 --> N1
    N2["Biquad tone/EQ<br/>1 Direct-Form-I section(s)<br/>b1,b0,b2,&minus;a1,&minus;a2, make-up"]
    N1 --> N2
    N3["C-format immediate loads (C40/C41)<br/>destination register UNKNOWN &mdash; the old 'envelope detector' reading is WITHDRAWN &times;5"]
    N2 --> N3
    N4["VOLUME<br/>output level"]
    N3 --> N4
    N5["REV SEND<br/>to reverb bus"]
    N4 --> N5
    N6["Output (RETURN to kernel epilogue)"]
    N5 --> N6

    classDef io fill:#e8eef7,stroke:#33475b,stroke-width:1px,color:#111;
    classDef proven fill:#d7f0d7,stroke:#2e7d32,stroke-width:2px,color:#111;
    classDef measured fill:#dbe9fb,stroke:#1565c0,stroke-width:1.5px,color:#111;
    classDef inferred fill:#fdf0d5,stroke:#b8860b,stroke-width:1.5px,color:#111;
    classDef open fill:#eeeeee,stroke:#888,stroke-width:1px,color:#333,stroke-dasharray:5 5;
    classDef ctrl fill:#f3e8fb,stroke:#6a1b9a,stroke-width:1px,color:#111;
    class N0,N6 io;
    class N1 inferred;
    class N2 measured;
    class N3 open;
    class N4,N5 ctrl;

Classic-topology match

Most likely textbook topology: LFO-swept delay (Doppler) + tone biquad (horn coloration).

A rotating-speaker model: an LFO sweeps a delay (Doppler pitch) into a tone biquad.

Instruction hint: LFO cell + delay-DRAM + a DF-I biquad, combined.

UI parameters (MEASURED, notes/kn5000-dsp-paramlist.md): DRIVE, VOLUME ADJUST, TREBLE DEPTH, FAST, SLOW, WIND UP, WIND DOWN, BASS DEPTH, BASS FAST, BASS SLOW, WIND UP, WIND DOWN, VOLUME, SLOW/FAST, REV SEND.

Per-instruction detail: ../disasm/prog15_rock_rotary.dsm. Confidence legend and method: README.md. Narrative: the MAME development blog, KN5000 effects-DSP series (Parts 78-84). Reference: the project docs site, /effects-dsp/.