Odyssey family: the Avatar, Axxe, Solus and Little Brother

bcox commented

2026-10-12 21:15:31 +00:00

Owner

Ben asked on 2026-10-12 which instruments of the families already here were missed, and for an issue a family. Everything below is from recollection, with no manual read; issue #20's list was wrong in several places for the same reason, so read the manuals first and correct this. Each is to be an extension of the existing instrument, as the Jupiters and the JX family are, never a "model" switch.

Avatar (1977): recalled as an Odyssey's voice with no keyboard, under a guitar pitch follower. Only the voice is of interest; sound from outside is #17.
Axxe (1975): recalled as roughly an Odyssey with one VCO and one ADSR.
Solus (1980): recalled as two VCOs with fewer routes than the Odyssey.
Little Brother: an expander of one VCO.

Third in Ben's order.

Ben asked on 2026-10-12 which instruments of the families already here were missed, and for an issue a family. **Everything below is from recollection, with no manual read**; issue #20's list was wrong in several places for the same reason, so read the manuals first and correct this. Each is to be an extension of the existing instrument, as the Jupiters and the JX family are, never a "model" switch. - **Avatar** (1977): recalled as an Odyssey's voice with no keyboard, under a guitar pitch follower. Only the voice is of interest; sound from outside is #17. - **Axxe** (1975): recalled as roughly an Odyssey with one VCO and one ADSR. - **Solus** (1980): recalled as two VCOs with fewer routes than the Odyssey. - **Little Brother**: an expander of one VCO. Third in Ben's order.

bcox commented

2026-10-12 22:00:39 +00:00

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Owner

Done on the family-extensions branch, commit 67d8652, not pushed. By Claude, with no one to ask; the choices are under "Open decisions" in CLAUDE.md.

What the manuals showed against the recollection here

Avatar: borne out. Its service manual (January 1978) says the synthesizer "is like the ARP Odyssey (in fact, the AVATAR and Odyssey use several of the same printed circuit boards)", and its specification is the Odyssey's figure for figure. It "is monophonic (single note)". No owner's manual was found.
Axxe: borne out, one VCO, one filter, one ADSR, with pink noise and a sample and hold of it. What the recollection left out: where the Odyssey has a slider and a switch, the Axxe has two sliders. Sawtooth and pulse each have a mixer slider; the pitch has four (LFO sine, LFO square, sample and hold, ADSR); the pulse width two (LFO, ADSR). Its depths are its own (the sine an octave either way, where the Odyssey's is half).
Solus: borne out, two VCOs, ring modulator, filter and ADSR, with no noise, no sample and hold, no AR and no high-pass. Each VCO has a slider from sawtooth to pulse; VCO 2's FM takes the ADSR or the LFO's square; the filter's envelope can be turned over; the trigger switch has SINGLE, MULT and AUTO. Its owner's manual was read as pictures, in part.
Little Brother: not "an expander of one VCO" in the Odyssey's sense. Only a parts list and drawings were found (Model 2950), and they show a VCO into a frequency divider and fixed wave shapers (16', 8', 4', 2'; brass, hollow, reed, fuzz), an attack-decay generator, an amplifier, an LFO with a vibrato delay, and no filter. Its sheet points to the Explorer's service manual. That is no setting of an Odyssey, so it was not built and is left for a decision: an instrument of its own, perhaps with the Explorer and Pro Soloist, or nothing.

What was built, each at nothing until asked for, so existing patches render as before:

mixer.vco1_pulse, mixer.vco2_pulse: a VCO's pulse in the mixer beside its sawtooth.
vco1.fm_square, vco2.fm_square, vco1.fm_adsr, vco1.pwm_adsr: a slider of its own for the LFO's square and the ADSR.
filter.sh: the sample and hold to the cutoff beside the LFO.
voice.one_pitch: both VCOs on the lowest key held (Solus, Avatar).
adsr.single: only a key struck with none held gives a trigger (Solus).
fm1, fm2 and pwm now go past the Odyssey's top, and the ADSR's times past its ranges, to hold the Axxe's and Solus's.

Nothing in engine/ changed. The Avatar's pitch follower and guitar input wait on #17. The bench did not move on the Pi (2.2%, 3.5%, 3.5%, 4.9% before; 2.1%, 3.5%, 3.5%, 4.9% after). Not played or heard.

Wants a word: the Little Brother; that the new sliders reach what the Odyssey's do and not the Axxe's or Solus's own figures; that three Odyssey sliders now run past their old tops; what SINGLE means, which the pages read do not say; and which way up the sawtooth is against the pulse, which can now be heard, since the two can be mixed.

Done on the `family-extensions` branch, commit 67d8652, not pushed. By Claude, with no one to ask; the choices are under "Open decisions" in CLAUDE.md. **What the manuals showed against the recollection here** - **Avatar**: borne out. Its service manual (January 1978) says the synthesizer "is like the ARP Odyssey (in fact, the AVATAR and Odyssey use several of the same printed circuit boards)", and its specification is the Odyssey's figure for figure. It "is monophonic (single note)". No owner's manual was found. - **Axxe**: borne out, one VCO, one filter, one ADSR, with pink noise and a sample and hold of it. What the recollection left out: where the Odyssey has a slider and a switch, the Axxe has two sliders. Sawtooth and pulse each have a mixer slider; the pitch has four (LFO sine, LFO square, sample and hold, ADSR); the pulse width two (LFO, ADSR). Its depths are its own (the sine an octave either way, where the Odyssey's is half). - **Solus**: borne out, two VCOs, ring modulator, filter and ADSR, with no noise, no sample and hold, no AR and no high-pass. Each VCO has a slider from sawtooth to pulse; VCO 2's FM takes the ADSR or the LFO's square; the filter's envelope can be turned over; the trigger switch has SINGLE, MULT and AUTO. Its owner's manual was read as pictures, in part. - **Little Brother**: not "an expander of one VCO" in the Odyssey's sense. Only a parts list and drawings were found (Model 2950), and they show a VCO into a frequency divider and fixed wave shapers (16', 8', 4', 2'; brass, hollow, reed, fuzz), an attack-decay generator, an amplifier, an LFO with a vibrato delay, and no filter. Its sheet points to the Explorer's service manual. That is no setting of an Odyssey, so **it was not built** and is left for a decision: an instrument of its own, perhaps with the Explorer and Pro Soloist, or nothing. **What was built**, each at nothing until asked for, so existing patches render as before: - `mixer.vco1_pulse`, `mixer.vco2_pulse`: a VCO's pulse in the mixer beside its sawtooth. - `vco1.fm_square`, `vco2.fm_square`, `vco1.fm_adsr`, `vco1.pwm_adsr`: a slider of its own for the LFO's square and the ADSR. - `filter.sh`: the sample and hold to the cutoff beside the LFO. - `voice.one_pitch`: both VCOs on the lowest key held (Solus, Avatar). - `adsr.single`: only a key struck with none held gives a trigger (Solus). - `fm1`, `fm2` and `pwm` now go past the Odyssey's top, and the ADSR's times past its ranges, to hold the Axxe's and Solus's. Nothing in `engine/` changed. The Avatar's pitch follower and guitar input wait on #17. The bench did not move on the Pi (2.2%, 3.5%, 3.5%, 4.9% before; 2.1%, 3.5%, 3.5%, 4.9% after). Not played or heard. **Wants a word**: the Little Brother; that the new sliders reach what the Odyssey's do and not the Axxe's or Solus's own figures; that three Odyssey sliders now run past their old tops; what SINGLE means, which the pages read do not say; and which way up the sawtooth is against the pulse, which can now be heard, since the two can be mixed.

bcox commented

2026-10-13 01:27:31 +00:00

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Closed by Ben's word on 2026-10-12. The work is on the branch family-extensions, not yet merged. The Little Brother is out, by Ben's word the same day.

Closed by Ben's word on 2026-10-12. The work is on the branch `family-extensions`, not yet merged. The Little Brother is out, by Ben's word the same day.

bcox closed this issue

2026-10-13 01:27:31 +00:00

bcox referenced this issue from a commit

2026-10-13 01:34:35 +00:00

Add the Avatar, the Axxe and the Solus to the Odyssey, and leave the Little Brother

bcox referenced this issue

2026-10-13 04:27:02 +00:00

New instruments: ARP's Odyssey, 2600 and Omni #22

bcox commented

2026-10-13 04:27:04 +00:00

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Owner

Ben played it on his laptop on the night of 2026-10-12, set as an Axxe, and found it looks good and sounds good. He confirmed the second sliders with no model switch, each reaching as the Odyssey's does; the three sliders that now go past the Odyssey's top; and adsr.single and voice.one_pitch as they are. The Avatar's guitar side still waits on #17. Everything said here is on main, pushed, on the night of 2026-10-12. What was heard was heard on Ben's laptop, not on the Pi.

Ben played it on his laptop on the night of 2026-10-12, set as an Axxe, and found it looks good and sounds good. He confirmed the second sliders with no model switch, each reaching as the Odyssey's does; the three sliders that now go past the Odyssey's top; and `adsr.single` and `voice.one_pitch` as they are. The Avatar's guitar side still waits on #17. Everything said here is on `main`, pushed, on the night of 2026-10-12. What was heard was heard on Ben's laptop, not on the Pi.

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Odyssey family: the Avatar, Axxe, Solus and Little Brother #34