Audiomovers Omnibus

A simple Omnibus setup: the DAW is addressing the first two channels of the Omnibus A device, which are being routed to both External Headphones and the speakers on my MacBook Air.

Omnibus takes audio from A to B, C, D and wherever else it’s needed!

If Audiomovers is a familiar name, it’s most likely because of ListenTo, which allows audio to be streamed over the Internet in real time. Abbey Road Studios liked this product so much they bought the company, having been told by their own engineers that ListenTo was the only solution they trusted for remote session work. But ListenTo is not the only problem‑solver in the Audiomovers line‑up, and even if you never need to send audio anywhere outside your own studio, tools such as Omnibus and Inject could prove invaluable. Inject is a cross‑platform utility that allows audio from secondary USB devices to be integrated into a DAW environment through a plug‑in insert, making it possible for example to record audio from a synth’s USB output whilst the DAW is still addressing your main audio interface.

Omnibus, by contrast, is Mac‑only, since it engages with Core Audio in a fairly deep way. In essence, it’s a routing matrix and aggregator that allows audio to be routed freely between all the different virtual and physical Core Audio devices in your system.

Driving The Bus

A small download from the Audiomovers website, Omnibus is authorised online, and gives you the choice as to whether it should run automatically when you boot your Mac, or wait until it’s called upon. It creates four virtual drivers of its own: the 16‑channel Omnibus A and B, the 32‑channel Omnibus C and the 64‑channel Omnibus D. These are addressable just like any audio device, from the Sound tab of System Preferences and from any Core Audio applications on your Mac.

Omnibus itself is a single‑window application, though its single window can end up being pretty large, especially if you have other virtual drivers such as the Pro Tools Audio Bridge installed. By default, the left‑hand panel shows a list of all the devices currently active on your Mac; this will include the four Omnibus drivers, system audio such as External Headphones and built‑in speakers, ‘systemwide’ programs such as Sonarworks Reference or dSoniq Realphones, and any connected Core Audio interfaces (hardware that also uses other driver protocols, such as Pro Tools HDX, can only be accessed through its Core Audio drivers). If a device presents input and output level or mute controls that can be changed within macOS, they’ll appear here. Each device also has a toggle that adds or removes it from the main patchbay.

Two other views are available for this left‑hand panel. Settings allows you to define a global sample rate and buffer size for Omnibus itself, and provides various other global configuration options. Snapshots lets you define up to 100 presets, nine of which can be assigned to hotkeys for instant recall.

The main part of the Omnibus window is taken up with the patchbay, which works pretty much like most other virtual routing matrices. Source channels are displayed on the vertical axis and destinations along the horizontal axis. To make a connection, you simply click, whereupon a blue line appears showing how the two are linked. A key Omnibus feature is that this matrix supports multing and combining in practically any configuration: there doesn’t seem to be a hard limit on how many sources you can route to a single destination, or vice versa. They don’t even have to be at the same sample rate: Omnibus quietly takes care of things like sample‑rate conversion behind the scenes.

Wild Ride

Some of the use cases that prompted Audiomovers to develop Omnibus probably apply only to a minority of SOS readers. For example, in an Atmos context you could use it to route a multi‑channel DAW output to your own 7.1.4 speaker system, to a separate binaural encoder, and to ListenTo for someone to audition the mix in a different country, whilst simultaneously hosting a Zoom call for remote talkback. But you don’t have to think very hard to find applications that are valuable even in more humble setups.

Right at the other end of the scale, for example, one of the frustrations of Core Audio on Apple laptops is that the External Headphones device vanishes when nothing is plugged into the headphone output. So you typically have to make a trip to your DAW’s audio preferences, or even close and reload the DAW session, every time you want to swap between headphones and a MacBook’s built‑in speakers. Needless to say, this gets old fast, but 30 seconds’ worth of clicking in Omnibus completely eliminates the problem. Select one of the Omnibus drivers as your DAW’s output device, plug in your headphones, and you can route the mix simultaneously to headphones and speakers. Unplug the headphones and the speakers will carry on. Best of all, when you plug the cans in again, Omnibus will remember and automatically restore the routing.

Run multiple audio programs simultaneously, integrate DAWs and virtual meeting software, record audio from your Web browser... the possibilities are endless.

There are innumerable other ways in which Omnibus can make itself useful. If you have a bunch of different USB audio devices connected, Omnibus can effectively aggregate them all, allowing you to track from multiple USB mics or synths at once. Want to set things up so that a systemwide headphone or monitor correction package only ‘sees’ one pair of outputs on your interface? No problem. Run multiple audio programs simultaneously, integrate DAWs and virtual meeting software, record audio from your web browser... the possibilities are endless. And what’s most impressive about it is the sheer robustness of the environment, which handles unexpected disconnections, sample‑rate changes and anything else you can throw at it without breaking sweat. If you’ve dabbled with aggregate and systemwide Core Audio devices in the past, you may well be nervous about using them for mission‑critical roles, but Omnibus appears to be bulletproof.