Aicd by mganss: Acid Basslines From an N-Gram Model
Most pattern generators in Max for Live are dice rollers. You set a density, a scale, a note range, and the device rolls until something sticks. Aicd by mganss works differently: it generates acid patterns using a maximum likelihood n-gram model. Instead of choosing each step independently, it picks the next step based on what tends to follow the steps before it. The result is a pattern with internal logic — notes, slides and accents that relate to each other the way a 303 line does, rather than a random walk that happens to land in key.
It is a MIDI effect, so it sits in front of whatever instrument you point it at. The device has been on the catalogue since December 2018, with the most recent update in January 2023 (version 1.5.1), and it runs on Live 11.2 with Max 8.5.1.
What the device actually produces
Aicd is a generator, not a sequencer you program step by step. You trigger generation and it hands you a pattern. From there the feature set has grown in a very specific direction over five versions, and the changelog reads like a list of workflow complaints being answered one by one:
- Clip creation (v1.1) — generated patterns can become real MIDI clips in the Session view, not just a stream of notes that disappears.
- A separate, MIDI-mappable generate button (v1.2) — so generation is a gesture you can put on a pad or a footswitch.
- Output clip and play toggle (v1.3) — a target clip plus transport control from inside the device.
- MIDI thru (v1.3.1) — your own playing passes through alongside the generated material.
- Pattern rotation (v1.4) — shift the pattern against the bar without regenerating it.
- MIDI-mappable preset recall (v1.4.1) — jump between stored settings from a controller.
Taken together, those additions tell you who the device is for. Generate, capture to a clip, rotate for variation, recall presets by hand. It is built to be played, not just auditioned. A demo video and a GitHub repo exist if you want to see it moving before installing.
Scenario one: filling an empty bass track in ten minutes
Put Aicd in front of a mono synth with a resonant filter and some envelope-to-cutoff. Drop it on a track with nothing in it, set the transport running over a kick and hat loop, and hit generate repeatedly while the loop plays. You are not sculpting — you are auditioning. Because the n-gram model produces patterns with recognisable acid phrasing, the hit rate is high enough that this is a fast process rather than a slog through noise.
When something works, use the clip creation feature to commit it. Now you have a MIDI clip you can edit by hand: pull one note down an octave, stretch a slide, delete the step that lands on the snare. The generator gets you to a strong first draft; your editing turns the draft into the part. That division of labour is the honest way to use Aicd, and it is why the clip creation feature matters more than it sounds.
Scenario two: a live acid channel you can steer
Map the generate button to a pad and preset recall to a second pad or an encoder. Now you have two performance moves that need no screen: new pattern, and new character. Add pattern rotation on a knob and you have a third — the same notes landing in a different place against the bar, which is a classic way to get a build out of material the audience has already heard.
The play toggle and output clip mean you can keep generation feeding a clip slot rather than firing notes straight into the void, so a pattern you like survives the moment it happened in. MIDI thru is the part people miss: with it on, you can play over the generated line from a keyboard — hold a root note, punch in an octave jump, let the machine handle the sixteenths. That is a much more musical performance setup than simply re-rolling until the crowd gets bored.
Scenario three: material for something that is not acid
Acid patterns are dense, syncopated single-note lines. That shape is useful well beyond a 303 emulation. Route Aicd into a plucked or percussive instrument and you get a busy arpeggio-like figure. Route it into a drum rack and the pitch movement becomes instrument selection — the pattern's note choices turn into a percussion line with the same rhythmic logic. Generate to a clip, then transpose the clip into a tighter range so it stops sweeping across the whole rack.
If the output is too loose for the rest of the track, chain it with a timing device rather than fighting the generator. Real-time MIDI Quantize by nonagon quantizes incoming notes — both note-on and note-off — to a selected beat interval, which is a blunt but effective way to lock generated material to a grid. Going the other way, Group Humanizer pulls timing off the grid in a way that is correlated across tracks, so a generated bassline and your drums drift together instead of separately. We looked at how that works in more detail in the Group Humanizer deep dive.
Where it sits among MIDI effects
The MIDI effect category is crowded, but Aicd's nearest neighbours in popularity are doing fundamentally different jobs. Group Humanizer (41,433 downloads) is about timing feel across multiple tracks. Real-time MIDI Quantize (27,472) is a utility. Architect by pmonet sits in the generative camp but has not been updated since 2015 and still targets Live 9.1.2 — its author announced a rewrite as an audio effect that never landed in this listing, so treat it as a historical curiosity rather than a working option on a modern system.
The real comparison is MK16-185 Sequencer by Kapetan, a modification of Nico Starke's ML-185 stage-controlled sequencer. That is a sequencer in the traditional sense: you set the steps, the stages, the gates. It gives you total control and total responsibility. Aicd gives you a model that already knows what an acid pattern looks like. If you enjoy programming sequencers, MK16-185 is the more interesting instrument; if you want a part now, Aicd is the faster route. MK16-185 also stopped at Live 9.1.7 in 2015 and sits at 4/5, while Aicd was maintained through Live 11.
What the numbers say
33,745 downloads, a 5/5 rating and 35 comments across six-plus years is a strong profile for a device this specialised. Generic utilities attract downloads by default; a device that only makes acid patterns has to earn them. The 2023 update — fixing a step calculation bug, after a 2022 pass for Live 11 — tells you the author kept reading reports and shipping fixes rather than abandoning the device after the initial wave of attention.
One practical caveat: the license field for Aicd is listed as None, so there are no stated terms here. If you intend to release music made with its output and want to be certain about rights, check the GitHub repo linked from the device page before you commit. Most generators in this space carry a Creative Commons variant — the alternatives above all do — and the absence of a stated license is a gap, not a permission.
Who should skip it
Skip Aicd if you are running older Live or Max; it targets Live 11.2 and Max 8.5.1, and older hosts are not what version 1.5.1 was built against. Skip it if you want to author every step yourself — a generator whose main control is "generate" will frustrate you, and MK16-185 Sequencer or a plain MIDI clip will serve you better. Skip it if you have no use for the acid idiom: this is not a general-purpose melody generator, and the model's whole value is that it is specific.
Everyone else should install it and spend a session doing nothing but hitting generate over a kick drum. Keep the three patterns you like, commit them to clips, and delete the device if you never touch it again. At worst you walk away with three basslines. If you want more starting points like this, the best-of lists and guides are organised around exactly that kind of fast test.