A separate audio input for each voice: the AX60's sampler connector #135

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opened 2026-10-05 23:46:14 +00:00 by bcox · 0 comments

bcox commented

2026-10-05 23:46:14 +00:00

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bcox asked on 2026-10-05 for a ticket for each engine gap in his moregaps.md feature table that no existing ticket covers. Engine claims are from reading the tree at f6aa8eba on main. Instrument claims are from that day's research, read as archive.org OCR of the AX60's owner's manual by a research agent and not re-checked; the sources are listed in that document. Nothing here is built, measured or listened to.

Summary

The Akai AX60's 13-pin input takes an Akai sampler's separate voice outputs, one into each synth voice, in place of that voice's VCO, so each sampled note passes through its own analog filter, VCA and the chorus. The sampler is put in MIDI mono mode, and the sample shares the patch's settings with the synth sound. That voice-to-voice alignment is an inference from the manual; the service manual's MIDI chart would settle it.

Here a channel has two input buses, external and sidechain, and every voice on the channel hears the same signal on each (dsp/mod_source.h:84-89). Six separate signals each into its own voice's filter have no route.

Two ways to it

Inside Tymbal, it is not a connector. A sampler built as a layer (#78) in the same voice feeds a VA layer's input tap per voice already, which is what the AX60 was wired to do with two boxes. That is the answer for a sampled note through a filter.
For outside signals, per-voice buses. N input buses on a channel, each assigned to the voice whose ordinal matches (which wants the voice-index ordinal of #132), fed from the physical input address space (fabric/port.h) as the two buses are. Six channels of a multichannel interface into six voices of one channel. This is the AX60 as a box, and also what a polyphonic external processor (one filter per string of a hexaphonic pickup) is.

Open

Whether 2 is worth having before a physical port table exists on the board with more than two inputs.
Voice assignment: the AX60 sends voice n on channel n; here an ordinal is assigned at note-on, so a note-on would have to arrive per bus (MIDI mono mode, one channel per bus) for the mapping to mean anything.

bcox asked on 2026-10-05 for a ticket for each engine gap in his `moregaps.md` feature table that no existing ticket covers. Engine claims are from reading the tree at `f6aa8eba` on `main`. Instrument claims are from that day's research, read as archive.org OCR of the AX60's owner's manual by a research agent and not re-checked; the sources are listed in that document. **Nothing here is built, measured or listened to.** ## Summary The Akai AX60's 13-pin input takes an Akai sampler's separate voice outputs, one into each synth voice, in place of that voice's VCO, so each sampled note passes through its own analog filter, VCA and the chorus. The sampler is put in MIDI mono mode, and the sample shares the patch's settings with the synth sound. That voice-to-voice alignment is an inference from the manual; the service manual's MIDI chart would settle it. Here a channel has two input buses, external and sidechain, and every voice on the channel hears the same signal on each (`dsp/mod_source.h:84-89`). Six separate signals each into its own voice's filter have no route. ## Two ways to it 1. **Inside Tymbal, it is not a connector.** A sampler built as a layer (#78) in the same voice feeds a VA layer's input tap per voice already, which is what the AX60 was wired to do with two boxes. That is the answer for a sampled note through a filter. 2. **For outside signals, per-voice buses.** N input buses on a channel, each assigned to the voice whose ordinal matches (which wants the voice-index ordinal of #132), fed from the physical input address space (`fabric/port.h`) as the two buses are. Six channels of a multichannel interface into six voices of one channel. This is the AX60 as a box, and also what a polyphonic external processor (one filter per string of a hexaphonic pickup) is. ## Open - Whether 2 is worth having before a physical port table exists on the board with more than two inputs. - Voice assignment: the AX60 sends voice n on channel n; here an ordinal is assigned at note-on, so a note-on would have to arrive per bus (MIDI mono mode, one channel per bus) for the mapping to mean anything.