The routing matrix decides which inputs reach which outputs, and at what level. This chapter explains the matrix, the Digital pair, link modes, switching between sources, and the USB audio modes.
The routing matrix
Open the device page and click the Routing tab.
Inputs run down the side in pairs: Aux 1 and 2, In 1 and 2, Digital 1 and 2. Outputs run across the top: Output 1, Output 2 and Output 3, plus Rec 1 and Rec 2 when the USB mode records (see USB audio modes below).
Each tile is one route, a crosspoint from one input to one output. The tile shows the route's level in dB. A dot means the route is off, and Ø means the route's polarity is inverted.
Editing a route
- Click a tile to select it. The tile's row and column are highlighted and the inspector below the matrix shows the route, for example "Aux 1 → Output 1".
- Drag up or down on a tile to change its level. Hold Shift for finer steps.
- ⌥-click (Option-click) a tile to invert its polarity.
- In the inspector, the On/Off toggle switches the route, the Level box takes a typed value in dB, and Polarity switches between normal and inverted.
Routes can only cut. The level runs from -60 dB to 0 dB, and setting -60 dB switches the route off. A route that is switched off remembers its level, so switching it on again restores the level.
Reset to defaults at the top of the panel restores the factory routing.
Factory routing
A new NEXUS, or one after a factory reset, mixes every input at once:
| Output | Receives |
|---|---|
| Output 1 | Aux 1 + In 1 + Digital 1, each at 0 dB |
| Output 2 | Aux 2 + In 2 + Digital 2, each at 0 dB |
| Output 3 | All six inputs at -6 dB, a mono sum |
| Rec 1, Rec 2 | The same as Output 1 and Output 2 |
Every connected source plays at once until you switch routes off. With one source connected, the factory routing plays it in stereo on Output 1-2 and in mono on Output 3.
The Digital pair: USB and S/PDIF
USB audio and the S/PDIF input share one input pair, Digital 1 and 2. NEXUS adds the two together before the matrix, so the Digital routes carry both.
The Digital sources grid under the matrix has a tile each for USB and S/PDIF. Select one to turn that source on or off and set its level. The level is applied before the two sources are added together, so it scales that source in every Digital route.
To hear only one of the two digital sources, switch the other one off here.
S/PDIF
- NEXUS accepts PCM stereo at up to 96 kHz on the coaxial input.
- NEXUS mutes the S/PDIF input until the signal has locked, and whenever the source sends compressed audio such as Dolby or DTS. Set the source to PCM or stereo output.
- Omnissiah shows no lock indicator. If S/PDIF stays silent, check the source's output format, then look in the device Settings tab under Activity for "SPDIF locked" or "SPDIF unlocked - muted".
Link modes
Inputs and outputs come in pairs, and a link mode makes a pair of routes move together. Select a tile and the inspector shows the pair's link control, for example Aux link, with three choices:
| Mode | What it does |
|---|---|
| Off | Each route is set on its own. |
| Stereo | 1 goes to Output 1 and 2 goes to Output 2, moving together. Choosing Stereo on a crossed tile (1 to Output 2) gives the crossed orientation, swapping left and right. |
| Sum | Both inputs of the pair go to the output together, as mono. |
Into Output 1-2 all three modes are available. Into Output 3, which is a single channel, the choices are Off and Sum.
The defaults are Stereo into Output 1-2 and Sum into Output 3.
Link modes are stored by Omnissiah on the computer, not in NEXUS. The routes themselves are stored in NEXUS.
Switching between sources
NEXUS has no input selector. To switch sources, switch routes on and off in the matrix, or switch USB and S/PDIF on and off in Digital sources.
For one-press switching, record each routing as a macro and trigger the macros from a MIDI or OSC controller. A macro's Capture records the changes you make in the matrix. The Control macros chapter of the Omnissiah manual covers macros and controllers.
Example: interface or turntable. An interface on Input 1-2 and a turntable preamp on Aux. Macro "Interface" switches the In routes on and the Aux routes off. Macro "Vinyl" does the reverse.
USB audio modes
The USB audio mode sets the sample rate and bit depth NEXUS offers to the computer, and whether NEXUS can record back to the computer.
To change mode, open the device Settings tab and find USB Audio. Choose a mode, then confirm Restart to switch USB mode? with Restart. NEXUS restarts and audio stops for about 2 seconds.
| Mode | Record to computer |
|---|---|
| 44.1 kHz · 16-bit · duplex | Yes |
| 48 kHz · 16-bit · duplex | Yes |
| 48 kHz · 24-bit (default) | No |
| 88.2 kHz · 16-bit | No |
| 96 kHz · 16-bit | No |
| 44.1 kHz · 24-bit | No |
NEXUS processes everything at 48 kHz, and other rates are converted inside NEXUS. Pick the mode that matches your computer's project or playback rate, so the computer does not resample as well. In 44.1 kHz · 24-bit, NEXUS truncates the audio to 16-bit.
Recording through NEXUS
In the two duplex modes NEXUS appears to the computer as a two-channel input as well as an output, and the matrix gains Rec 1 and Rec 2 columns. Route any input to Rec 1 and Rec 2 to record it on the computer, for example a turntable on Aux or an S/PDIF source.
