How tabula-emu simulates the console

tabula-emu is a console without audio: it holds every parameter of an X32/M32, speaks its OSC protocol, and computes what a console computes on its own (meters, status, links between strips). No sound goes in or out; levels come from a synthetic signal that follows what you do on the mix, so meters and the RTA react like on a console with a band playing.

This page says what is simulated, how, and what is not.

Parameters and protocol

• Every parameter of a scene (about 3240 nodes, 12800 parameters), plus the preferences and status pages (/-prefs, /-stat, /-show, /-libs, /-usb, /-urec, /-action…). Values are stored as the console stores them: floats quantized to its steps, text written exactly as in its scene files.
• Get and set of every parameter, node text with /node and /, node sets with several values, /xremote: a change is pushed to the other clients. Changes the console makes itself (linked partners, status values) are pushed to every client, the one that caused them included.
• Status the console computes: /-stat/solo, /-insert (where each effect is inserted), /-ha/NN/index (headamp feeding each channel, from its source and the input routing), /-stat/rtasource (from /-action/setrtasrc).
• Library: scenes, snippets and presets (/save, /load, /copy, /delete, /rename, /add, /showdump). A recall applies the stored values as they are; scene safes and snippet filters are not applied yet.

Audio flow (meters)

Each meter frame is computed from the current parameters:

1. Inputs. Every channel with an input source gets a signal breathing between about −42 and −14 dBFS, different for each channel. Aux inputs carry no signal. Headamp gain and trim do not change it.
2. Channel strip. The gate attenuates by its range while the signal is under the threshold; the compressor applies its threshold and ratio (no knee, attack or release). Then mute and fader.
3. Sends. Each bus send applies its on switch and level, taken after the fader when its tap is POST, before it otherwise.
4. Buses. Sends add up in power; then bus dynamics, mute and fader. A bus assigned to the main L/R feeds it.
5. FX returns. FX slots 1-4 fed from a bus (/fx/N/source) return half of that bus’s level into FX returns 1-8; their strips then work like channels (fader, mute, sends, L/R).
6. Mains. Channels and buses assigned to L/R add up there, and to the mono bus through their mono level; then dynamics, mute and fader.
7. Matrices. Fed by their sends from L/R, mono and the buses; then dynamics, mute and fader.
8. DCAs show the loudest of their channels. Outputs show the level of the source patched to them.

Not simulated: pan and balance (left and right always carry the same level), delay, polarity, the EQ (it only shapes the RTA, below), insert effects, mute groups and DCA faders/mutes acting on the sound, solo and the monitor bus, talkback, oscillator, automix, USB/card playback.

The meter blobs have the sizes the editors expect (M32-Edit drops a blob of the wrong size): /meters/0 70 values, 1: 96, 2: 49, 3: 22, 4: 82, 5: 27, 6: 4, 7: 16, 8: 6, 9: 32, 10: 32, 11: 5, 12: 4, 13: 48, 14: 80, 15: 50 (100 packed RTA bands), 16: 48.

RTA

/meters/15 analyses one source, chosen by the editor with /-action/setrtasrc (the emulator keeps it in /-stat/rtasource):

Source	Meaning
0-31	channels 1-32
32-39	aux inputs 1-8
40-47	FX returns 1L-4R
48-63	buses 1-16
64-69	matrices 1-6
70, 71	main L/R, mono
72, 73	monitor, talkback
74-89	dual graphic EQ A/B of FX slots 1-8
90-97	stereo graphic EQ of FX slots 1-8
+ 98	the same, after the EQ

M32-Edit selects the channel shown on its EQ page, or the graphic EQ open on its FX page. A graphic EQ hears the strip it is inserted on.

The spectrum is synthetic: a broad hump around the source’s level, moving a little. The channel low cut shapes it, and after the EQ (source + 98) so do the EQ bands or the graphic EQ faders: move a band and the RTA follows. A source with no signal shows nothing, as on a console: with every fader and send down (a fresh scene), the buses, matrices and their graphic EQs are silent.

M32-Edit draws the RTA only above −(range + gain) dB, from the /-prefs/rta values: 30 dB range and the RTA gain, or 60 dB range and gain30 when range is ON.

Effects

The emulator stores effect parameters but does not process sound. /fx/N/par/01…64 follow the effect loaded in the slot: all 61 effects are modelled with the ranges, steps, formats and defaults of M32-Edit, and loading another effect resets the slot to its defaults. The FX send and return meters (/meters/9) follow the FX returns; the effects’ own meters (/meters/10 and 14) stay idle.

Linked strips

Odd and even strips can be linked in pairs: channels (/config/chlink/1-2 … 31-32), aux inputs (auxlink), FX returns (fxlink), buses (buslink) and matrices (mtxlink). The console keeps a linked pair in step; editors rely on it when connected (M32-Edit only links strips itself in its offline mode). The emulator does the same:

• A change a client makes on one strip of a linked pair is applied to the other strip, and pushed to every client.
• Linking a pair copies the odd strip to the even one.
• Turning a link option on copies, in every linked pair, what that option covers from the odd strip to the even one.

What follows the partner:

Parameters	Linked
name, icon, input source	never
pan, send pans	never
gate and compressor key sources, insert selection (FX5L / FX5R…)	never
delay, preamp (trim, polarity, low cut); for channels, the headamp of their inputs (gain, phantom)	with /config/linkcfg/hadly
EQ	with /config/linkcfg/eq
gate, compressor, insert on and position	with /config/linkcfg/dyn
fader, mute, L/R and mono assignments, mono level	with /config/linkcfg/fdrmute
everything else: colour, sends (on, level, tap), DCA and mute groups, automix	always

These rules come from M32-Edit’s offline logic, and match the linked pairs saved by a real M32C: in its scenes the two strips of a pair differ only in name, icon, source, pans and insert selection.

Recalling a scene or a snippet applies the stored values without linking them.

Verified with M32-Edit

Mixer → PC (M32-Edit reading the emulator) runs without any unhandled request. Checked in M32-Edit: meters, the RTA on the EQ page and in the graphic EQ editor (pre and post, following the faders), and linked channels moving together. Fixed along the way:

• PC → Mixer: M32-Edit writes each node with the line feed of /node replies, which the emulator rejected; it now accepts it (tested by writing a whole scene the way M32-Edit does).
• RTA: source numbering as above, and the four undocumented /-prefs/rta fields named as M32-Edit names them (rtaoneq, rtaongeq, range, gain30).
• Linked strips, as above.

See testing with the editors to check it yourself.