Audio signal flow

The audio path of the whole rig, block by block, as read on the rig on 2026-11-10. Each block is its own diagram and can be read alone.

Legend. Solid arrows (-->) are audio. Dashed arrows (-.->) are control (OSC) or clock (PTP, SAP announcements). Subgraphs are machines. A label with (?) marks something that could not be verified; each one is listed under Open points at the end. “Live” means read on the rig on 2026-11-10 with pw-link -l, pw-top -b, pw-metadata -n settings and cat of configs (read-only). Port names are exactly as PipeWire/JACK show them.

1. Rig overview

Three machines carry audio: a3nuc1 (Core engine, deck A, the Scarlett), a3motionV02 (deck B) and a3nuc2 (deck C). Decks B and C reach the Core as AES67 streams on the audio network (192.168.9.0/24); the Core sends one stream back (AES67 a3nuc1 out, carrying REC) that the deck hosts receive for their recorders. Controllers only send OSC.

        flowchart LR
  subgraph N1["a3nuc1 · Core + deck A · 192.168.9.10"]
    SDA["StemDeck-A"]
    ENG["a3-engine"]
    CORE["a3-core Core (OSC)"]
    BAN["beat-analyzer"]
    RXB["AES67 deck B (receiver)"]
    RXC["AES67 deck C (receiver)"]
    TXO["AES67 a3nuc1 out (sender, 12 ch)"]
    TXZ["AES67 Core MAIN / BOOTH / REC / PHONES (senders)"]
  end
  subgraph N3["a3motionV02 · deck B · 192.168.9.23"]
    SDB["StemDeck-B (?) stopped at read time"]
    TXB["aes67-deck-b (sender, 41 ch)"]
    RXO3["AES67 a3nuc1 out (receiver)"]
  end
  subgraph N2["a3nuc2 · deck C · 192.168.9.20"]
    SDC["StemDeck-C"]
    TXC["aes67-deck-c (sender, 41 ch)"]
    RXO2["AES67 a3nuc1 out (receiver)"]
  end
  SCAR["Scarlett 18i20 3rd Gen (USB on a3nuc1)"]
  SRC["Analog sources (?)"]
  PA["PA main 4.1 (?)"]
  HP["Headphones (?)"]
  ARC["Analog recorder (?)"]
  BTH["Booth (?) no receiver found"]
  CTL["Mixer · desk · Motion UI · pro-DJ apps"]

  SRC --> SCAR
  SCAR -->|"capture 1-8"| ENG
  SDA -->|"JACK, 41 links"| ENG
  SDB -->|"(?)"| TXB
  SDC -->|"41 links"| TXC
  TXB -->|"RTP multicast"| RXB
  TXC -->|"RTP multicast"| RXC
  RXB --> ENG
  RXC --> ENG
  ENG -->|"main 1-5, phones 9-10, rec 11"| SCAR
  SCAR --> PA
  SCAR --> HP
  SCAR --> ARC
  ENG --> SDA
  ENG --> BAN
  ENG --> TXO
  ENG --> TXZ
  TXZ -.->|"AES67 Core BOOTH"| BTH
  TXO -->|"RTP multicast"| RXO2
  TXO -->|"RTP multicast"| RXO3
  RXO2 -->|"rec_L/R"| SDC
  RXO3 -.->|"(?) deck B stopped"| SDB
  CTL -.->|"OSC :9000"| CORE
  CORE -.->|"OSC :9004"| ENG
  CORE -.->|"PTP grandmaster (ptp4l)"| N2
  CORE -.->|"PTP grandmaster (ptp4l)"| N3

Sources: live pw-link -l/pw-top on a3nuc1, a3nuc2, a3motionV02; ip -br a on each; truth a3-osc.json (hosts, aes67_streams, listeners); systemctl --user is-active on each host.

2. One StemDeck deck (one-deck -bformat instance, StemDeck-<X>)

Four stereo stems pass their stem knob (the “pre-mute block”), then each stem is split into a moving share (IEM StereoEncoder at the stem’s pose) and a steady share (a SteadyBed of four fixed sources), summed to 3rd-order B-format. The instance exposes exactly 43 output ports (B-format, AUX, cue, phones) and two inputs (rec_L/R); it has no stereo buses.

        flowchart LR
  FILE["Stem file (NI Stems)"] --> PLAY["Player: 4 stereo stems (8 ch)"]
  PLAY --> KNOB["Stem knob (gain) = pre-mute block"]
  KNOB -->|"moving share g·x"| SENC["Per stem: IEM StereoEncoder (az / el / width)"]
  KNOB -->|"steady share (1-g)·x"| SBED["SteadyBed (MultiEncoder, 4 bed sources)"]
  MOT["DeckMotion one-shots, deck 3D"] -.->|"pose, g"| SENC
  SENC --> MSUM["Main sum, order 3 SN3D, 16 ch"]
  SBED --> MSUM
  MSUM --> MUTE["Stem MUTE after the encoder (R5)"]
  MUTE --> OBF["bformat_1..16"]
  KNOB --> AUXS["Per-stem AUX send 0..1"]
  AUXS --> ABUS["AUX bus 16 ch (encoder out + steady via aux bed)"]
  ABUS --> OAUX["aux_1..16"]
  KNOB --> CUES["Per-stem CUE switch (pre-mute)"]
  CUES --> CBED["Cue bed, 3rd-order sum"]
  CBED -->|"ACN 0..8 only"| OCUE["cue_1..9 (2nd order)"]
  CBED --> PDEC["BinauralDecoder (standalone use)"]
  PDEC --> OPH["phones_L / phones_R (not linked on rig)"]
  IREC["rec_L / rec_R (inputs)"] --> RECF["Recorder: 24-bit FLAC"]

Sources: a3-stemdeck/Source/DeckSpatial.h (stems pre-mute, g·x / (1-g)·x, R5, cue = first 9 ACN, aux bus, phones decoder), Outputs.h (outputs::oneDeck::layout, 43 ports, portName), SpatialLaw.h (order = 3, bformatChannels = 16, stemsPerDeck = 4), SteadyBed.h, StemDeckPlayer.h (pre-mute block, cue send pre-mute), Recorder.h, DeckLinks.h; live a3nuc1/a3nuc2 (phones_* unlinked). The two-deck StemDeck’s five stereo buses (1-4 + AUX, Buses.h) are the legacy mode and are not drawn.

3. Deck-to-Core transport

Deck A is a local JACK client linked straight to the engine. Decks B and C each run a PipeWire module-rtp-sink with 41 channels (MAIN1-16, AUX1-16, CUE1-9) in the PTP group, announced by SAP; the Core’s module-rtp-sap turns every session matching ~^AES67 deck into a 41-port receiver with a 4 ms buffer, whose ports engine.json links onto the engine’s deck slot.

        flowchart LR
  subgraph HA["a3nuc1 · deck A (local)"]
    SA["StemDeck-A: bformat_1..16 · aux_1..16 · cue_1..9"]
  end
  subgraph HB["a3motionV02 · deck B"]
    SB["StemDeck-B (?) stopped"]
    TB["aes67-deck-b · 'AES67 deck B' · 41 ch S24BE · ptime 0.25 ms · sess.latency 1 ms"]
  end
  subgraph HC["a3nuc2 · deck C"]
    SC["StemDeck-C: bformat · aux · cue"]
    TC["aes67-deck-c · 'AES67 deck C' · 41 ch S24BE · ptime 0.25 ms · sess.latency 1 ms"]
  end
  SAPG["SAP/SDP 239.255.255.255:9875"]
  subgraph HCORE["a3nuc1 · Core"]
    RB["AES67 deck B: receive_MAIN1..16 · AUX1..16 · CUE1..9 · sess.latency 4 ms"]
    RC["AES67 deck C: receive_MAIN1..16 · AUX1..16 · CUE1..9 · sess.latency 4 ms"]
    EA["a3-engine deckA_1..16 · deckA_aux_1..16 · deckA_cue_1..9"]
    EB["a3-engine deckB_1..16 · deckB_aux_1..16 · deckB_cue_1..9"]
    EC["a3-engine deckC_1..16 · deckC_aux_1..16 · deckC_cue_1..9"]
    ED["a3-engine deckD_* (?) mapped to StemDeck-D, not running"]
  end
  SA -->|"41 JACK links"| EA
  SB -->|"(?) 41 links"| TB
  SC -->|"41 links"| TC
  TB -->|"RTP 239.69.150.245:5004"| RB
  TC -->|"RTP 239.69.150.246:5004"| RC
  TB -.->|"announce"| SAPG
  TC -.->|"announce"| SAPG
  SAPG -.->|"rule ~^AES67 deck"| RB
  SAPG -.->|"rule ~^AES67 deck"| RC
  RB -->|"MAIN→deckB_n · AUX→deckB_aux_n · CUE→deckB_cue_n"| EB
  RC -->|"MAIN→deckC_n · AUX→deckC_aux_n · CUE→deckC_cue_n"| EC

Sources: live pw-link -l on a3nuc1 and a3nuc2; live ~/.config/pipewire/pipewire-aes67.conf (a3nuc1), pipewire-aes67-deck-C.conf (a3nuc2), pipewire-aes67-deck-B.conf (a3motionV02); template a3-stemdeck/tools/pipewire-aes67-deck.conf.in (sess.latency.msec = 1, 41 channels); live engine.json io.jack (deckA-D maps); truth aes67_streams.deck (group base .244, step 1); a3-doc/src/ressources/aes67.md.

4. Core engine inputs and channel strips

Four channels (N = 4 on the rig); each selects one source: its analog pair or a deck slot. Analog goes through the stereo strip and is encoded at the channel’s position (moving band) plus the shared steady bed; a deck’s 16 B-format channels go through the 16-channel deck strip and are added to the bus directly. AUX sends feed enc_fx and the beat-synced DualDelay, whose output is the FX Return.

        flowchart LR
  subgraph INP["a3-engine inputs"]
    AN["analog_1..8 (Scarlett capture 1-8)"]
    ANX["analog_9..12 (not linked)"]
    DKB["deckX_1..16 (B-format), X = A..D"]
    DKA["deckX_aux_1..16"]
  end
  AN -->|"pairs 1/2, 3/4, 5/6, 7/8 → ch 1-4"| SEL["ChannelSelect per channel: analog pair or deck k (channel.source)"]
  DKB --> SEL
  SEL -->|"analog"| CST["ChannelStrip: TRIM → 3-band EQ → DJ filter → 3D band (Isolator3) → VOLUME"]
  SEL -->|"deck k"| DST["DeckStrip 16 ch: TRIM → EQ → SVF filter → VOLUME"]
  CST -->|"moving, at azimuth/elevation"| AEB["AmbiEncoderBus (IEM MultiEncoder, order 3)"]
  CST -->|"steady → bed sources"| AEB
  AEB --> EMAIN["enc_main (16 ch)"]
  DST -->|"16 ch post-VOLUME, added directly"| EMAIN
  CST -->|"× AUX send"| EFX["enc_fx"]
  DST -->|"× AUX send"| EFX
  DKA --> DST2["2nd DeckStrip on the channel's controls, VOLUME at unity"]
  DST2 --> EFX
  EFX --> DDL["IEM DualDelay, 2nd order: BEAT · FEEDBK · COLOR · SPREAD"]
  DDL --> RET["FX Return × RETURN"]
  CST -.->|"pre-VOLUME / post-VOLUME taps"| EPH["enc_phones (block 6)"]
  DST -.->|"pre-VOLUME / post-VOLUME taps"| EPH

Sources: a3-core/PROGRAM.md (Plan 4a: Channels, Buses, FX Return, delay page, Orders), src/a3-engine/Engine.h (graph comment), ChannelStrip.h, DeckStrip.h, AmbiEncoderBus.h; live engine.json (channels 4, analogPairs [1,2,3,4], analogInputs 12, filterKind svf); live pw-link -l (only analog_1..8 linked). A deck channel ignores positions, 3D, FREQ and Q (PROGRAM.md), except one on a deck in stereo mode, which plays through the analog strip and takes them as an analog channel does. The dashed taps into enc_phones are audio drawn dashed only to keep this block readable; block 6 draws them solid.

5. Core spatial mixing and outputs

enc_main plus the FX Return feeds three decoders: main and booth (IEM SimpleDecoder, AllRAD 4.1, 3rd order) and rec (IEM BinauralDecoder, 2nd order). Main and booth pass MASTER/BOOTH, then the calibration trim and gate; every output port goes both to the Scarlett (where mapped) and to its own AES67 stream.

        flowchart LR
  EMAIN["enc_main (order 3, 16 ch)"] --> BUS["main bus = enc_main + FX Return"]
  RET["FX Return"] --> BUS
  BUS --> DMAIN["SimpleDecoder main: tops ±45°, ±135°, sub on ch 1 (150 Hz)"]
  BUS --> DBOOTH["SimpleDecoder booth: same 4.1 layout"]
  BUS --> DREC["BinauralDecoder rec (2nd order)"]
  DMAIN --> MAS["MASTER (master.volume)"]
  DBOOTH --> BOO["BOOTH (master.booth)"]
  MAS --> TMAIN["trim main −30 dB + gate"]
  BOO --> TBOOTH["trim booth −30 dB + gate"]
  DREC --> TREC["trim rec 0 dB, never gated"]
  TMAIN --> PMAIN["main_sub, main_top_1..4"]
  TBOOTH --> PBOOTH["booth_sub, booth_top_1..4"]
  TREC --> PREC["rec_L, rec_R (block 7)"]
  PMAIN -->|"playback 1-5 (sub, T1-T4)"| SCAR["Scarlett 18i20 outputs"]
  PMAIN --> SMAIN["AES67 Core MAIN · 5 ch SUB,T1-T4 · 239.69.200.1"]
  PBOOTH --> SBOOTH["AES67 Core BOOTH · 5 ch · 239.69.200.2"]
  PBOOTH -.->|"no analog output linked"| NOB["booth speakers (?)"]
  SCAR --> PA["PA main 4.1 (?)"]

Sources: PROGRAM.md (Outputs, Orders, Gate), Engine.h, Engine.cpp decode() (busMain += busFx; main/booth/rec from busMain); data/spatial/main.decoder.json and booth.decoder.json (loudspeakers at az 45, −45, −135, 135, el 0, on decoder channels 2-5; imaginary ±90° el), main.parameters.json (swMode 1, swChannel 1, low/high pass 150 Hz), variant.json (“Default 4.1”); live engine.json (trimsDb main −30, booth −30, phones 0, rec 0; spatial both /usr/share/a3-engine/spatial); live pw-link -l (main → playback_AUX0..4, booth only → rtp-sink-core-booth); live a3nuc1 pipewire-aes67.conf (Core senders: 5/5/2/2 ch, ptime 0.5 ms, sess.latency 3 ms, S24BE).

6. Cue and phones path

The phones bus collects each channel’s pre-VOLUME tap (when its CUE is on) and post-VOLUME tap, weighted by the CUE↔MIX knob, the delay’s output (with RETURN on the mix side, and as a PFL when the return’s cue is on), and every deck’s 9-channel stem cue. One 2nd-order BinauralDecoder renders it; the headphone EQ is off on the rig.

        flowchart LR
  subgraph DECKS["StemDeck-A..D"]
    SCUE["cue_1..9 (cued stems, ACN 0..8, pre-mute)"]
  end
  SCUE -->|"deckX_cue_1..9, local or AES67 CUE1..9"| WSC["× cueWeight (CUE↔MIX), on a channel or not"]
  CHPRE["channel pre-VOLUME tap"] -->|"channel.cue on"| WCUE["× cueWeight"]
  CHPOST["channel post-VOLUME tap"] --> WMIX["× mixWeight"]
  DDL["DualDelay output"] --> WRET["× (RETURN × mixWeight + cueWeight if aux-return.cue)"]
  WSC --> EPH["enc_phones (order 3; decoder reads ACN 0..8)"]
  WCUE --> EPH
  WMIX --> EPH
  WRET --> EPH
  EPH --> BDEC["BinauralDecoder phones, 2nd order, KU100 HRIR, phonesHeadphoneEq off"]
  BDEC --> PHV["PHONES (master.phones-volume)"]
  PHV --> PHT["trim phones 0 dB + gate"]
  PHT --> PPH["phones_L, phones_R"]
  PPH -->|"playback 9-10"| SCAR["Scarlett 18i20"]
  PPH --> SPH["AES67 Core PHONES · 2 ch · 239.69.200.4"]
  SCAR --> HP["Headphones (?)"]

Sources: Engine.h (enc_phones and phones lines), Engine.cpp (addStemCues, cue/mix/returnCue weights), PROGRAM.md (Stem cue R13, Orders: headphone decoders 2nd order, KU100 data), EngineConfig.h (phonesHeadphoneEq “off” or an IEM headphone model); live engine.json (phonesHeadphoneEq: "off", phones → system:playback_9/10); live pw-link -l (phones_L/R → playback_AUX8/9 and rtp-sink-core-phones); truth (channel.cue, master.phones-mix, master.phones-volume, aux-return.cue).

7. REC path

rec_L/R (the binaural rec decoder, block 5) fans out to five places: the Scarlett, StemDeck-A’s recorder, the beat-analyzer’s tempo input (left only), the legacy 12-channel AES67 a3nuc1 out stream (CH1/CH2, the one the deck hosts receive for their recorders) and the AES67 Core REC stream.

        flowchart LR
  PREC["a3-engine rec_L / rec_R"]
  PREC -->|"L and R both onto playback 11"| SCAR["Scarlett 18i20 out 11"]
  SCAR --> ARC["Analog recorder (?)"]
  PREC --> SDA["StemDeck-A rec_L/R → FLAC"]
  PREC -->|"rec_L only"| BAN["beat-analyzer:bpm_1"]
  PREC -->|"built-in link → CH1/CH2"| TXO["rtp-sink 'AES67 a3nuc1 out' · 12 ch · 239.69.150.243 · sess.latency 3 ms"]
  PREC --> TXR["rtp-sink-core-rec 'AES67 Core REC' · 2 ch · 239.69.200.3"]
  TXR -.-> NOR["receiver (?) none found"]
  subgraph HC["a3nuc2"]
    RXC["AES67 a3nuc1 out · receive_CH1/2 · sess.latency 12 ms"] --> SDC["StemDeck-C rec_L/R → FLAC"]
  end
  subgraph HB["a3motionV02"]
    RXB["AES67 a3nuc1 out (receiver)"] -.->|"(?) StemDeck-B stopped"| SDB["StemDeck-B rec_L/R"]
  end
  TXO -->|"RTP multicast"| RXC
  TXO -->|"RTP multicast"| RXB

Sources: live pw-link -l on a3nuc1 (rec_L/R → StemDeck-A:rec_L/R, playback_AUX10, beat-analyzer:bpm_1, rtp-sink:send_CH1/2, rtp-sink-core-rec:send_L/R) and on a3nuc2 (AES67 a3nuc1 out:receive_CH1/2 → StemDeck-C:rec_L/R); live pw-top on a3motionV02 (AES67 a3nuc1 out node present, nothing linked); PROGRAM.md (built-in links P40/P46, beat-analyzer link, P39); live engine.json (rec_L, rec_R → system:playback_11); a3-stemdeck/tools/pipewire-stemdeck-aes67.conf.in (rule ~ out$, 12 ms); a3-stemdeck/Source/Recorder.h.

8. Clock and sync

One sample clock: the Scarlett drives a3nuc1’s graph; a3-core --role clock steers the audio port’s PTP hardware clock to it, ptp4l on the Core serves it as grandmaster, and the deck hosts’ PipeWire graphs are driven by PTP0-Driver from their PTP-locked clocks. The beat clock (BTrack on the rec signal) and StemDeck’s Pro DJ Link are tempo, not sample clock.

        flowchart LR
  subgraph N1["a3nuc1"]
    SCAR["Scarlett 18i20 (ALSA driver) · quantum 64 @ 44100 Hz"]
    PROF["pw-profiler -J (10 ms records)"]
    CLK["a3-clock: --role clock · LOCKED"]
    PHC["PHC /dev/ptp0 on enp5s0"]
    PTPM["ptp4l@enp5s0 · MASTER · free_running"]
    G1["engine, StemDeck-A, receivers, senders follow the Scarlett"]
    BAN["beat-analyzer (BTrack)"]
    CORE["Core tempo follower"]
    ENGD["engine DualDelay tempo"]
  end
  subgraph N2["a3nuc2 / a3motionV02"]
    PTPS["ptp4l@enp5s0 / ptp4l@eth0"]
    PTPD["PTP0-Driver · clock.system.ptp0 · resync 1.5 ms · quantum 64 @ 44100"]
    DECK["aes67-deck-c / -b, StemDeck-C, AES67 a3nuc1 out receiver"]
    SDT["StemDeck: Pro DJ Link (tempo master option)"]
  end
  RECL["a3-engine rec_L"] -->|"bpm_1 (audio)"| BAN
  SCAR -.->|"driver clock records"| PROF
  PROF -.-> CLK
  CLK -.->|"clock_adjtime ADJ_FREQUENCY"| PHC
  PHC -.-> PTPM
  SCAR -.->|"drives graph"| G1
  PTPM -.->|"PTP 224.0.1.129 :319/:320"| PTPS
  PTPS -.-> PTPD
  PTPD -.->|"drives graph"| DECK
  BAN -.->|"/beat"| CORE
  SDT -.->|"/stemdeck/deck/tempo"| CORE
  CORE -.->|"/delay/bpm (?) inputs"| ENGD
  SDT -.->|"prolink :50000-50002"| PDJ["Pro DJ Link network"]

Sources: PROGRAM.md (“The one clock: –role clock”, “Block on PipeWire”); live a3nuc1 $XDG_RUNTIME_DIR/a3/clock.json (master scarlett-ptp, health locked, frequencyPpm 14.37, errorNs 594) and /run/a3/ptp-state.json (MASTER); live pw-top (a3nuc1: Scarlett input node drives at quantum 64, PTP0-Driver idle; a3nuc2 and a3motionV02: PTP0-Driver drives at 64); live pw-metadata (all three: clock.rate 44100, clock.quantum 64, force-quantum 0); live pipewire-stemdeck-aes67.conf (PTP0-Driver, resync.ms 1.5); pgrep ptp4l on the deck hosts; live 20-a3-profiler.conf; truth (ptp4l.event/general, beat, stemdeck.tempo, delay.bpm, prolink.*, clockmode); CLAUDE.md (beat-analyzer clock modes 0/1/2).

9. Control paths that move audio parameters (OSC, not audio)

Every controller talks only to Core (core.osc, UDP 9000); Core passes what the engine needs on engine.osc (loopback 9004) and switches StemDeck instances on stemdeck.osc (7780 + deck − 1). Positions only move analog channels; a deck’s movement is StemDeck’s own.

        flowchart LR
  MIX["A³ Mixer"] -.->|"gain, eq, volume, aux-send, cue, filter, master.*"| CORE["Core :9000"]
  DESK["desk / pro-DJ apps"] -.->|"same words, channel.stem.push"| CORE
  MOT["Motion UI"] -.->|"azimuth, elevation, 3d, filter freq/q"| CORE
  CORE -.->|"engine.osc :9004: strips, positions, channel.source, delay.*, engine.open"| ENG["a3-engine"]
  CORE -.->|"stemdeck.osc 7780 + k−1: stemdeck.3d, bus switches"| SDK["StemDeck-A..D"]
  ENG -.->|"engine.hello, deck audio state"| CORE
  ENG -.->|"/vu bundles → core.vu-relay :9003"| CORE
  CORE -.->|"/vu, lamps, relays"| MIX
  CORE -.->|"/vu, relays"| MOT

Sources: truth a3-osc.json (listeners, routes, addresses: channel.*, master.*, channel.azimuth/elevation/3d from motion, channel.source, aux-return.delay.*, engine.open, engine.hello, engine.deck-audio, stemdeck.3d, stemdeck.bus); PROGRAM.md (positions on engine.osc 9004; deck channel ignores positions/3D/FREQ/Q; /vu meters).

Latency budget

Stage

Value

Kind

Source

PipeWire block, all three hosts

64 frames @ 44.1 kHz = 1.45 ms

configured

live pw-metadata, engine.json blockSize 64

Core digital round trip (Scarlett S/PDIF loop) at Block 64

212 samples = 4.8 ms

measured (2026-11-06)

PROGRAM.md “Block on PipeWire”

same at Block 128 (before)

343 samples = 7.8 ms

measured

PROGRAM.md

Deck sender (B, C)

sess.latency.msec 1 ms, packet 0.25 ms

configured

live deck-B/C confs, template

Core deck receiver

sess.latency.msec 4 ms (2 and 3 ms crackled at Block 64)

configured

live a3nuc1 conf, PROGRAM.md

Deck → Core, calculated

7.3 ms

calculated, assumes a 3 ms sender

PROGRAM.md STATUS row

Core senders (MAIN/BOOTH/REC/PHONES, out)

sess.latency.msec 3 ms, packet 0.5 ms

configured

live a3nuc1 conf

Deck host receive of AES67 a3nuc1 out

sess.latency.msec 12 ms

configured

live a3nuc2 / a3motionV02 conf

Deck → Core end to end, Core → booth

—

not measured

—

Open points

  1. Deck B audio: stemdeck@B was inactive on a3motionV02 at read time (sender a3-aes67-deck@B and stemdeck-aes67 active). Its links into aes67-deck-b and from AES67 a3nuc1 out are assumed to match deck C’s.

  2. Deck D: engine.json maps deckD_* to a local StemDeck-D on a3nuc1; no such client ran, and which host would play deck D was not checked.

  3. What is plugged into the Scarlett: the port mapping is verified (capture 1-8 → analog_1..8; out 1-5 main, 9-10 phones, 11 rec, 12 round-trip loop), but the PA, headphones, analog recorder and analog sources behind them are not.

  4. Booth: no analog output is linked (booth_* only to AES67 Core BOOTH), and neither deck host receives any AES67 Core * stream. The booth zone is sent as a stream; which receiver plays it is up to the installation.

  5. Deck internals: whether a one-deck instance applies a deck fader, and whether MUTE also acts on the AUX and cue buses (the cue is pre-mute by design), was not checked in code.

  6. Core’s tempo follower: which inputs it uses for /delay/bpm (/beat from the analyzer, deck tempo, or both) was not read.

  7. analog_9..12: the engine has 12 analog inputs, only 1-8 are linked. The stale return stereo row was removed from aes67.md.

  8. rec on one output: rec_L and rec_R both go to Scarlett out 11 (L+R summed), verified live and in engine.json; the maintainer corrects this in the engine configuration.

  9. Small source drifts: the live round-trip loop is channel 12/12 (PROGRAM.md names 11 as the default); PROGRAM.md’s 7.3 ms deck-to-Core calculation assumes a 3 ms sender while the shipped and live sender is 1 ms; PROGRAM.md puts MASTER after the decoder, Engine.h before (linear gain, no audible difference).

  10. Mermaid syntax: no Mermaid CLI is installed locally (mmdc absent; adding it would be a new dependency), so the diagrams were checked by eye only.