Connecting a Sound Mixer to DMXDesktop

Find your mixer

USB figures are channels sent to the computer x channels coming back from it.

Not listed? Almost every mixer has a line-level output of some kind, and the analogue method works with those for the price of a small USB interface.

Choosing a connection method

There are three ways to get audio into DMXDesktop. Pick the first one that describes your situation.

Wherever you have the choice, send DMXDesktop a stereo mix of the music only. Speech microphones, talkback and announcements in the feed make the lights chase whoever is speaking, and they wreck tempo detection because speech and applause read as transients. If the music is a live band, its instruments and vocals are the music, so they belong in the feed.

The channel rule

This one rule explains most of the "I set it up and got silence" reports, so it is worth understanding before you touch the console.

It matters because several consoles put their main mix high up the USB list by default. A Yamaha DM3 sends its stereo bus on 17 and 18, and a Yamaha TF records it on 33 and 34. Those are reachable on macOS, and on Windows through ASIO. On Windows without ASIO you need a console setting that puts the mix you want on the pair the ordinary device carries, and not every console has one. The Allen & Heath Qu is a helpful exception: its driver feeds the ordinary Windows stereo input from USB 17 and 18, which is where Qu puts Main LR by default.

The left and right channels do not have to be next to each other. Select the two channels carrying your intended left and right signals. Each console article says which case applies to it.

Before you plug anything in

Beyond that:

• Use line-level outputs only: Record Out, Tape Out, Aux Out, Matrix Out, Control Room Out, Monitor Out or Main Out.
• Start with the output level low and bring it up.
• Do not feed DMXDesktop's own audio output back into the input it is analysing.
• On a digital console, name the bus you set aside DMXDesktop or Lighting so the next person does not undo it.
• Use a microphone in front of a speaker only as a last resort, when there is no electrical connection available at all.

Building a music-only feed

Wherever the console allows it, give DMXDesktop a feed with the music in it and the speech left out. There is more than one way to get one:

• A dedicated stereo bus: an Aux, Mix, Matrix or group pair with only the music channels sent to it. This is the most flexible, and the steps below walk through it.
• The direct outputs of the music channels, when the music arrives on its own pair of inputs.
• A subgroup, ALT output or monitor mix that already carries only the music.
• Capturing the music at its source, for example the audio output of the computer playing it.

Throughout these guides, keeping microphones out means speech: a compere, announcements, talkback. If the music comes from a live band, its instrument and vocal channels are the music, so keep them in.

A dedicated bus, step by step

1. Pick two unused buses and link them as a stereo pair, or use a stereo bus. Name it DMXDesktop or Lighting.
2. Unmute the bus and set its master fader to 0 dB.
3. On each music channel, set the send to the bus at 0 dB and leave the channel unmuted. Keep the stereo image intact: a stereo source sends left to the left side and right to the right, and a mono source is panned centre.
4. On every speech microphone, talkback and announcement channel, turn the send to the bus fully down or switch it off.
5. Choose pre-fader or post-fader sends, as explained below.
6. If the console asks for a tap point on the bus output feeding USB, choose post-fader so the bus master sets the level.
7. Patch the bus left and right to a USB output pair, and select those two channels in DMXDesktop.

Pre-fader or post-fader

There are two separate choices, and they do different things.

• The send from each channel to the bus. Post-fader sends follow each channel's own fader, so pulling a music channel down in the room also turns it down in the lighting feed. Pre-fader sends ignore the channel fader, so the feed stays steady while someone rides faders. Pre-fader audio does not stop because a channel fader is down.
• The tap on the bus output. This decides whether the bus master fader affects what reaches USB.

Neither choice makes the feed exactly what the audience hears. A post-fader direct output follows only that one channel's fader, not the main master. A dedicated music bus does not pass through main-bus processing unless you route it that way, and nothing captured at the console includes processing further down the line, such as in the PA system. For lighting that rarely matters: the analysis needs the music at a steady, healthy level.

If you are not sure, use post-fader sends, so the lights calm down when the music is pulled down.

Setting it up in DMXDesktop

Once the console is sending audio down the USB cable, the DMXDesktop side is the same for every mixer.

1. Open Settings → Audio.
2. Pick your mixer or interface from the Audio Input Device list. The list is grouped, so ASIO devices, loopback devices and ordinary devices are easy to tell apart.
3. On an ASIO device a Configure ASIO… button appears. That opens your driver's own control panel, where the buffer size lives. Input gain is handled by the driver, so DMXDesktop's volume slider is disabled and the loopback option does not apply.
4. If Input channels pickers appear, set the left and right channel numbers to match what you patched on the console. If they do not appear, you are on a device where DMXDesktop always captures the first two channels the device offers.
5. Start the music and check that the input meter moves.
6. Enable Live Wire, or your beat-driven effect cues, and watch a quiet passage and a drop to confirm the response makes sense.

Live Wire is available on the Standard and Pro plans. Beat and tempo detection drive effect cues on any plan that includes them.

Setting the level

1. Turn the interface input gain down, if it has one.
2. Play a loud, representative section of the music, not an intro.
3. Bring the mixer's output level up until DMXDesktop's input meter sits in a healthy range.
4. Back off if it sits at the top. Continuous full-scale readings mean clipping, and a clipped signal has no dynamics left for the analysis to work with.
5. Check both channels respond.
6. Save the console's show file or scene so the routing survives a power cycle.

This feed does not need to sound good. It needs to be clean, stable, unclipped and to have the bass and transients intact. That is all the analysis is looking at.

Common problems on any mixer

The device appears but DMXDesktop hears silence

Almost always the USB output patch. Getting a channel to the main mix and getting the main mix onto a USB output are two separate pieces of routing on most consoles, and doing the first does not do the second.

Only one side works

Only one half of the pair got patched, or the left or right channel selected in DMXDesktop is not the one carrying that side. The two channels do not need to be next to each other, but each must carry the right signal. Check both.

The lights react to speech

Speech microphones are in the feed. Give DMXDesktop a music-only feed instead, as described in Building a music-only feed above. Every console article covers the options for that desk.

Windows offers no channel choice

You are on the mixer's ordinary Windows device rather than its ASIO driver, so DMXDesktop captures the first two channels that device offers. See the channel rule above.

It worked last week and now the channels are wrong

If you saved a high channel pair and then connected a smaller interface, DMXDesktop falls back to channels 1 and 2 and tells you it has done so, rather than quietly capturing the wrong thing. Re-select the pair you want once the right interface is connected.

The mixer meters move but the computer gets nothing

Check you are not looking at the USB return patch, which controls audio going the other way. Check too that no other application is holding the driver: ASIO drivers are frequently single-client, so a DAW left open will lock DMXDesktop out.

Feedback or a building echo

USB playback on its own does not cause feedback. A loop happens when audio captured from the console is played back into a USB return, and that return is part of the same mix being captured. Keep USB returns out of the feed you send to the computer, or stop the computer playing the captured audio back.

Wi-Fi is connected but there is no audio

Wi-Fi and Ethernet carry mixer control on almost every console of this type. Audio travels over USB, or over a dedicated audio network such as Dante. Connecting the tablet app does not connect the audio.

Questions people ask

Main LR or a dedicated bus?

Main LR is the fastest to set up and is fine if the desk only ever handles music. In every other case a music-only feed is better, because it keeps speech microphones out. A dedicated stereo bus is the most flexible way to build one, but direct outputs, subgroups and monitor mixes can also work.

Can DMXDesktop use channels 17 and 18 instead of 1 and 2?

Yes, on macOS and on Windows via ASIO. The numbers do not matter, and they do not have to be next to each other. They only have to carry the left and right of the mix you want.

Can I use one channel instead of a pair?

Yes. Set the same channel number for both left and right and DMXDesktop treats it as mono. A real stereo feed analyses better, so prefer it where you have one.

Can a DAW and DMXDesktop share the interface?

Sometimes. It depends on the driver. ASIO drivers are often single-client, in which case you have to close the DAW. If DMXDesktop reports the device is already in use, that is what has happened.

Why does macOS show so many channels?

That is normal for a multichannel Core Audio device. Pick the exact pair you patched.

Can I just use the laptop's built-in microphone?

It works, and it is the worst option available. It picks up the crowd, the room, the compere and every reflection. Use it to prove the concept, then connect something.