Troubleshooting

• Check the cable is in the UAC port. The 5V ⎓ 2A port supplies power only and carries no data.
• Use the supplied cable, or another USB-C cable that carries data. Some USB-C cables only charge.
• Look at the STATUS LED. Dark means no power: try another USB port on the computer. Red that never turns white, or yellow, means NEXUS did not start properly (below).
• Plug NEXUS straight into the computer rather than through a hub.
• Quit Omnissiah and open it again.

Something failed while NEXUS was starting. Unplug the USB-C cable, wait five seconds and plug it back in. If the LED stays red or turns yellow again, message us and say which colour you see.

Work from the source towards the speakers:

1. 1Is the source playing into NEXUS? For USB audio, set the computer's sound output to Tantrum Nexus. For S/PDIF, see below.
2. 2Does the SIGNAL LED flash green? If it does, NEXUS is passing audio, so check the speaker cables, the speakers' power and their volume.
3. 3Is the input routed? On the Routing tab, check that the source's routes to Output 1 and Output 2 are on. USB and S/PDIF also need their tiles on under Digital sources.
4. 4Is an output muted or turned down? On the Mixer tab, check each output's mute and the Master volume.
5. 5Is a crossover set wrongly? A high pass at 200 Hz on a small speaker, or a low pass on the main pair, removes most of the sound. Check each output's Crossover tab.

• NEXUS plays PCM stereo only. Set the source (TV, streamer, console) to PCM or stereo output, not Dolby, DTS or "bitstream".
• Check the source's sample rate is 96 kHz or lower.
• Check S/PDIF is on under Digital sources, and the Digital routes are on.
• On the device Settings tab, Activity shows "SPDIF locked" when NEXUS receives a valid signal and "SPDIF unlocked - muted" when it loses it.

The factory routing sends a mono sum of every input to Output 3. Switch off the Output 3 routes you do not want on the Routing tab.

An output is clipping. Turn the source down, or lower that output's gain. A large EQ boost added by hand can also push an output into clipping.

• Use balanced TRS leads for the inputs and outputs.
• Plug the computer, the interface and the powered speakers into the same mains socket or strip.
• If the hum stops when you unplug the USB-C cable, the computer's ground is the cause. Run the computer from its battery while listening, or after setup power NEXUS from a USB-C supply in the 5V port instead.

The level meter never turns green.

• Check 48 V phantom power is on for the microphone input.
• Check Mic in Settings → Audio is the right interface and channel.
• Check Output Device is the interface wired into NEXUS Input 1-2, and that the interface's output volume is up.
• Hold the Test output buttons in Settings → Audio to confirm each speaker plays.

The meter turns red. Lower the microphone gain on the interface, not the speaker level.

The wrong speaker plays. Swap the leads at NEXUS Input 1-2, or check that Left Speaker uses Output 1 and Right Speaker uses Output 2 in the System list.

A measurement keeps restarting. The reading is unstable. Quieten the room, switch off fans, keep still, and check the microphone stand is not touching the desk. Then click Restart this measurement.

The corrected sound is worse. The microphone was probably not where your head is, or it moved during measurement. Check the placement in Chapter 3 — Quick start, step 5, and measure again. Bypass all on the Applied Correction page returns to the uncorrected sound in the meantime.

The computer cannot record from NEXUS. Recording works only in the two duplex USB modes. On the device Settings tab, set USB Audio to 48 kHz · 16-bit · duplex or 44.1 kHz · 16-bit · duplex, then route the inputs you want to Rec 1 and Rec 2 (Chapter 7 — Routing & sources).