SQ and Dante: recording channels, patching and backup coverage

Channel counts, sample rates and DVS licenses

Write down the required track count, sample rate and DVS license before changing the patch. Keep a copy of the current routing so you can restore it after the test.

The card and DVS have different limits

Identify the card model. The fitting note AP13279 Issue 1 lists M-SQ-DANT32 and M-SQ-DANT64 operation at 48 or 96 kHz. Network channel capacity does not add processing channels to the mixer.

The Audinate version comparison lists these capacities. The DVS table in the 4.5.x manual (p.27) applies to Gigabit networking and 24-bit audio; the 100 Mb/s table has lower limits. Use these figures to plan the patch, then test the complete recording session.

1. Define the session you need

   For example, you may need 48 separate sources at 96 kHz. With an M-SQ-DANT64 card and standard DVS, the receiver is limited to 32 channels. Pro increases DVS capacity, but does not increase the capacity of a 32-channel card or the number of available sources.

2. Check the channels DVS makes available

   Check Licensing, About, Audio Channels, the wired network interface and the sample rate. To change Audio Channels, quit the DAW and stop DVS, then restart DVS before reopening the application (manual, p.24). On Windows, select ASIO for a compatible DAW; WDM provides 16 channels as eight stereo pairs (p.39). On macOS, the interface is Core Audio.

3. Recheck the channel count after changing the sample rate

   The manual, p.22, warns that increasing the sample rate can reduce Audio Channels, and lowering it does not automatically restore the previous count. Make changes outside a recording, with the application closed, then check the channels available in the DAW again.

Green check but no audio: trace the socket and channel separately

The card connects two patching stages. The fitting note, p.2, distinguishes internal SQ patching from routing in Controller. SQ §6.1, pp.23–24, explains the matrix axes and the Patch button. Save the existing patch before changing crosspoints.

For example, DVS Tx1/2 can feed SQ Dante Rx39/40. Inside SQ, I/O Port sockets 39/40 must then feed the intended processing channels, which could also be 39/40. Using the laptop's transmit channel numbers in the SQ matrix would select a different path. Read the source and destination labels: two matrices can display their axes differently.

1. For an input to SQ

   Record the Tx device and channel, Rx device and channel, I/O Port socket and SQ channel. In I/O > Inputs > Input Channel, select the socket receiving the subscription and the channel that should receive it; enable Patch to edit. Test a known source at a controlled level and watch the channel meter.

2. For recording from SQ

   Follow the path in the other direction: SQ source → I/O Port output → card Tx → DVS Rx → track input. Section 6.6, p.26, explains that routing between devices is still needed after the signal reaches the card.

3. If the DAW still has no signal

   Confirm that DVS started before the application, the correct audio device is selected and the track uses the correct input (DVS manual, pp.38–39). If the patch matches but there is still no signal, check the source, clock and subscription status using the linked Dante guide. Raising gain before locating the break can produce an excessive level when audio returns.

Choose the signal for each recorder

To record a signal taken from the processing channel, check Direct Out and its tap point. To copy the socket without channel processing, review Tie Lines in Connections and Patching. Send Main LR as two signals when you need the event mix. Choose the tap for the recording's purpose and listen to it: matching channel numbers do not guarantee matching signals.

This is a proposed patch for one source and a mix, not a record of a completed recording. Sockets 1/2 are reserved for LR and the example source uses socket 3. Adapt it to the show without overwriting existing assignments.

Two computers: what the backup covers

In this example, one computer receives Dante and another receives USB-B. This lets you test a normal stop of the main application without both recordings depending on that computer. The paths share the source, preamp and SQ. Two computers alone do not establish continuity if one of those shared components fails.

Before connecting cables, record the port mode. The SQ Dante 64 specifications list Switched and Redundant modes. Do not assign Primary/Secondary ports based on which computer you call the main or backup recorder. The DVS manual, p.28, specifies a wired Ethernet interface. Document the network path to each receiver and the link failure it covers; do not assume automatic failover on the computer.

Record the clock arrangement too. The DVS 4.5.2.3 Windows release notes state that non-Pro licenses require another Dante hardware device or a separate computer running Dante Via as clock leader. Pro adds functions from 4.5.0 onward, but does not make sources or the rest of the path independent. The SQ Internal/I/O Port clock setting depends on the intended clock source; follow the clocking and audio dropout guide.

Rehearse the recording and inspect the files

Complete the SQ/Dante recording and backup worksheet: mixer and card, firmware, DVS/license, DAW/version, operating system, adapter, network, sample rate, clock and the patch for each source. Results fields are blank.

Make a rehearsal recording with the planned track count and duration. Identify every source at the beginning and repeat a reference at the end. Close both recordings normally, open their files separately and check channels, starts, ends and overlapping coverage. Compare the recordings before preparing a delivery.

In a separate practice take, stop the main recording normally and inspect the backup file to see whether it covers the following interval. Stop recording before stopping DVS, as required by its manual, p.25. This check does not require cutting power or removing storage during a write.

The worksheet helps detect specific errors: assuming a 64-channel card means a 64-channel receiver at every sample rate, confusing Tx1/2 with Rx39/40, recording an input other than the subscribed one, or claiming backup coverage for a source that never reaches the second recorder. For USB, see simultaneous recording and backup coverage; for file delivery, see event recording handoff. Plan the patch with audio systems and coordinate audiovisual delivery with cameras and streaming.