Live Voiceover Session Tip: Loopback Routing – Tuesday Tech Tip

Loopback routing in the home voiceover studio can be mysterious and confusing. How do we send audio back out of our computer to someone connected in a session? Since we often have to achieve this inside of our computer, rather than with physical cables, it’s helpful to understand how we route our audio in the “virtual” realm.

Last week I talked about routing audio cables in the home voiceover studio, and how audio quality can sometimes be negatively impacted by nearby electrical cords and various power supplies. 

There is a simple test to whether you have an interference issue: If your audio doesn’t have weird hums or buzzes, then you are probably fine. Decent cables are generally pretty well shielded, and not all power supplies cause interference. You may have routed your cables in a way that works flawlessly. It’s worth digging into those details only if you are having strange interference issues in your recordings. Those can crop up after adjusting equipment positions in your setup, or after you add new gear. A small shift of the positioning of the cables may cause them to react to an electrical field. 

The nice thing about dealing with physical cables is that you can actually see them. It lets us easily visualize where the audio signal flows. In my setup, th mic plugs into a cable, which goes out around the back of the booth and then connects to the audio interface on the desk. Clean and simple. Nice and logical. 

Routing Digital Signals

Things get a bit trickier to conceptualize as we move into the “virtual” realm – that is to say when the connections and routing occur inside of the computer. We don’t have the benefit of touching physical cable ends and being able to trace them back or forward to the specific location. We have to “see” it in our mind.

The benefit with virtual routing is versatility. Once our audio gets converted from the analog realm into digital information – changed from the continuous voltage which travels down our XLR cables into USB data – it can show up in some helpful places. 

You are already doing this. The “audio” which moves from your interface to your computer is digital data. That’s how we store, edit, and manipulate it in our recording software. We send that data back out to our interface and it shows up at our headphone connection where we hear it as sound. It gets converted back into an audio signal before being sent to our headphones (or monitors). Any audio interface does this core task of direct input and output (I/O). 

Software Control Panels for Your Audio Interface

These days, we’re seeing more audio interfaces building functionality on top of this simple I/O task. Many of the newer interface models now have software control panels which let you send various audio signals to different places. Universal Audio’s Apollo series was probably the first widely used interface that let voice actors redirect audio data in this manner. The Apollo was really designed to work in a recording studio setting to overcome limitations in computer based multitrack recording. Many of the options aren’t really necessary for what we do in the VO studio, but there is one very helpful feature which can be important – Loopback. 

If we’re not in a Source-Connect session where the client is recording our audio feed on their end, we may get asked to play back an earlier take that we have recorded. 

What does that “Loopback” control do on your audio interface?

Some interfaces have a physical “Loopback” knob to achieve this. It’s one of the features I’ve always liked about the Yamaha AG03 and AG06 interfaces. You can think of Loopback as a mirror that reflects audio back out to everyone listening. When you turn up the Loopback signal, the audio comes out of your recording software and the interface sends it back through your computer to them. 

This Loopback circuit only sends the signal from your recording. This type of signal is known as a “Mix Minus” –  a mix of your audio, minus the “far end”s (director’s) voice. That lets you play a recording back to them without creating an echoing feedback cycle. You may have heard that annoying feedback result in a Zoom session where someone has both a phone and a computer active. When the phone picks up the computer sound, it begins to repeat itself while increasing in volume. 

Controlling your audio interface from your computer

In the stress of managing a session, I generally prefer a hardware control to handle loopback to a director. However, with some interfaces, you can also set up this type of routing in a software control panel. The ease of achieving this depends entirely on how the manufacturer lays out their software. I touch on this a bit in one of my Presonus Revelator io24 videos. Things can get a little harder to conceptualize when everything happens in a software control panel, but I will say the designs are becoming less cryptic. 

Apollo and RME have robust and versatile systems. The new SSL control panel which came out with their new interface looks very clean. Presonus Universal Control software sets up nicely, though they have had some maddening updates which actually removed some functionality. Audient has been refining their ID and EVO control panels. 

All of which is to say that the “next” interface you may purchase is likely to have features which will be accessed through the computer, rather than on the device itself. As long as the interface manufacturers choose to emphasize logical workflows which let us focus on performance, this continues to be a good development. 

Routing Playback Audio to a Google Meet Session

Speaking of audio routing, I found a hack to send audio to a Google Meet session from my recording software. This lets you use the ZoomAudioDevice driver to send recorded audio to a browser-based connection session.

Want to receive these resources (and more!) the day they come out?
Each week I send out a new article to my email community focused on creatively using recording technology in your home voiceover studio, and how to balance those technical challenges with the need to be brilliant behind the microphone.
If you would like to join in to receive those emails the day they publish, please take a moment to share your contact information through this sign up form.
Thank you!

If this resource has been helpful to you, please consider sharing it with one of the buttons below!