DiGiCo SD10: MADI, Optocore and monitor returns

Not directly to the Optocore port. The SD10 has separate BNC MADI connections and an Optocore interface; using fiber does not make the two systems compatible. HMA identifies a connector. Some HMA-equipped devices carry MADI, while others belong to an Optocore network.

For an optical MADI source, use a compatible optical-to-coaxial converter to reach an SD10 BNC MADI input. A connector adapter does not convert the protocol. An Optocore connection requires an interface with a documented bridge function that is compatible with the actual network.

1. Identify the transmitter, connectors and output protocol. Record the sample rate, channel format, fiber type and optical specification. Check those details against the exact receiver or converter; a cable that fits is not sufficient evidence of compatibility.
2. Check the SD10 optical card and Optocore version before altering a ring. Getting Started B distinguishes V220 for DiGiRack/MiNiRack from V221 for SD Rack, SD MiNiRack, NaNoRack and D-Rack. That table does not establish compatibility for every firmware version or rack.
3. For the BNC MADI path, prepare the cabling before powering up, as the manual specifies. Connect the converter’s coaxial output to the MADI input identified in the patch, using 75 Ω cable. Do not repurpose a rack backup connection without checking which redundancy you would lose.
4. In Setup → Audio I/O, match Device Type and Connection to the physical device and port. Use the appropriate generic socket labels for standard MADI; changing a label does not change the signal. A green connection indication lets you proceed with patch checks, but does not establish that all channels carry the intended audio.
5. With the session saved and output levels safe, check Audio Sync against the planned clock source for the whole system. A green OK indicator detects a valid clock even when that source is not selected; check the selection too. Send a known signal on one MADI channel and watch the assigned input channel meter. With no link, trace protocol, fiber, converter and BNC. With a link but no signal, check the transmitted channel and selected socket. If you hear clicks, check clocking and sample rate before changing EQ or gain.

MADI Split provides a copy of the rack inputs; it does not return monitor mixes by itself. Rack Routing Mode selects the SD Rack return source. Connecting FOH to Main and a second console to Aux does not automatically divide the physical outputs between them.

If the SD10 is connected to the rack’s active return, one option is to receive the monitor mixes on another MADI port and copy them to unused SD Rack output sockets. Copy Audio handles this path without using processing channels. Check available ports, MADI capacity, clocking and software on both consoles first; the following steps cover the SD10 return path.

1. Save both sessions and draw the input split and mix return as separate paths. Identify the physical output required by each FOH and monitor bus, including card and socket numbers. Lower the affected output levels before changing routes.
2. Read Rack Routing Mode and Rack Routing Order on the SD Rack. RxM selects Main, RxX selects Aux, and OPTO selects Optocore. In AUTO with MXO order, the rack uses Main when it detects a valid stream, then looks for Aux and Optocore. Do not change that priority during operation to try to combine two returns: a valid stream does not necessarily carry the mixes you need.
3. Check the cable carrying monitor mixes. It must reach an available, configured SD10 MADI IN, not a rack MADI Split output. In Audio I/O, verify the link, received sockets and actual output cards. If the only cable installed sends rack inputs to the monitor console, the return path is still missing.
4. In Setup → Copy Audio, expand the input port receiving the mixes and the SD Rack output port. Make one copy to a free output socket and test it before adding others. A blue column identifies an output already in use or not allocated to the console. Check its allocation and patch; do not erase PA, recording or other output routes simply to free it.
5. Test a known monitor bus at low level on the chosen physical output. If the signal reaches the SD10 but not the socket, check the copy cell, the rack’s active return source and channel/bus output routes: an output route can overwrite a copy. If it does not reach the SD10, trace the monitor console send, link and clock before changing the rack.
6. The first copy becomes the Listen Source. Leave Listen To Copied Audio in the state intended for the show; enabling it changes the source heard by the associated channels, except for inputs protected by Listen Safe. Copy Audio settings are not recalled by changing snapshots; they persist in the session. Record the previous patch so you can restore it. Do not use Unroute All Outputs as a shortcut to recover audio. First check the manual for the installed software to establish which routes it affects and how to restore them.
7. Keep this audio path separate from preamp control. In Splits & Sharing, Full Control sends gain, phantom and pad settings to the rack; Receive Only receives settings without changing them; Isolate stops the control exchange. Decide who controls the rack before rehearsal. That setting does not divide physical outputs or replace the monitor mix return.

No. A 56-channel SD Rack connection at 96 kHz needs both SD10 MADI ports. DiGiCo TN294 specifies 1A + 2A or 1B + 2B; 1A + 1B are redundant connections for the same port. The first port carries channels 1–28 and the second carries 29–56. Renaming sockets or conforming cards cannot supply channels missing from the second link.

The rear panel has four IN/OUT connector pairs, but Getting Started B describes two MADI interfaces with redundant connections. Plan channel capacity and backup separately. A complete bidirectional rack connection at 96 kHz uses two pairs of BNC cables.

1. Save the show and record the patch before unplugging anything. Read the session sample rate in File → Session Structure, then check the rack and receiving device. You can inspect the setting without changing it. A 96 kHz session and a split set to SYS/2 can deliver different sample rates.
2. Compare the patch drawing with the rear-panel labels 1A/1B and 2A/2B. For 56 SD Rack channels at 96 kHz, check that both channel blocks reach the chosen connections on ports 1 and 2. Draw each IN and OUT separately. A second cable on a redundant port is not a second logical port.
3. In Setup → Audio I/O, check the link device and sockets. SD Rack at 96 kHz uses SMUX. For a Std MADI interface, check its manual for 56/64-channel framing and 48K Frame/SMUX or 96K Frame/Hi-Speed compatibility. These names describe the data arrangement: 96 kHz audio can use SMUX with a 48 kHz frame.
4. Check which ports remain available for recording, monitor returns and backup. TN294 requires two logical MADI ports for 56/64 inputs and outputs at 96 kHz. Do not treat A/B redundancy as another full-capacity link without checking the console implementation. If the available ports cannot carry the plan, revise the signal paths before loading the show.
5. During rehearsal, send an identifiable source to channels 1, 28, 29 and 56 one at a time and note the receiving socket. This checks the endpoints and block boundary; test every required channel afterwards. If channels 29–56 are missing, trace the second port and its patch. If audio reaches the wrong channels, check the output frame and receiver format before rearranging tracks.
6. For recording from SD Rack MADI Split, check Main/Aux, ON/OFF/GT, SYS/SYS/2 and MADI type. At 48 kHz, selecting 64ch does not add audio inputs on channels 57–64. At 96 kHz, the mode and channel blocks depend on the output settings; record the actual configuration. Restore the saved cabling and settings if a test makes the link worse.

Check the selected clock source, not just the OK indicator. On the SD10, green OK means a valid clock is detected at that input, even when the console is using a different source. Then check sample rate, MADI format and cabling. That indicator does not verify the recorded file or every audio channel.

Clicks alone do not identify a clock fault. Set up a test that separates the source signal, the MADI link and capture on the computer. Keep one coherent clocking plan for the whole system.

1. Note when the clicks occur, which channels they affect and whether they are audible in the console too. At rehearsal, compare a known source on the SD10 with its recorded track, keeping the recorder return out of the listening path. If the console source already contains the noise, check that upstream path before blaming the recording.
2. Open Setup → Audio Sync and record the selected source and session sample rate. The SD10 supports internal clock and Word Clock, AES/EBU, MADI or installed Optocore references. Trace the clock source for every device. Avoid a loop in which console and interface both wait to sync to each other without an independent reference.
3. For a direct link with the SD10 providing the reference, check the interface manual for how to follow incoming MADI from that console. If the system uses Word Clock or Optocore, preserve that clocking design; selecting MASTER on the SD10 is not a general repair. Issue E specifies Audio Sync = Optocore for connected engines during normal Optocore operation.
4. Compare the actual sample rates of the console, interface and recording project. At 96 kHz, also check 56/64-channel framing and SMUX versus Hi-Speed. TN294 explains that incompatible formats can put audio on the wrong receiving channels. If the symptom is a displaced track, correct the format before blaming the clock.
5. With affected outputs at a safe level and the patch recorded, replace only the suspect BNC segment with a verified 75 Ω cable. Check connectors and intermediate panels. If the symptom changes, examine that complete segment. If it persists, restore the original cable before testing another variable.
6. If the problem changes with the venue power arrangement, have qualified personnel assess the electrical installation. TN294 warns that ground differences can affect coaxial MADI. Keep protective earth connected; this test does not involve removing it or taking measurements on an energized installation. A fiber conversion requires the exact converter model and confirmed MADI support, as explained in the first question.
7. Record an identifiable passage, listen to the file and note whether the clicks recur. If clock, format and link remain stable but capture still fails, continue with the interface, driver and recording-software documentation. Do not prescribe a buffer size or update for unidentified hardware. Audio Sync is stored with the session: check it when restoring the previous show.