If you want to record a full band with 24 inputs and 6 stereo headphone mixes, or if you want to use a rack of outboard gear for mixing, that means you’re going to need a huge 32×32 audio interface… Right?
Well… actually, no. Thanks to digital audio protocols, you can use a relatively affordable audio interface with only 2 or 4 mic preamps and expand your interface to suit your needs for years to come.
In this blog, I’ll share ideas for choosing an interface (or using your existing interface) to do more than you might think possible by simply looking at the number of mic preamps and analog I/O on the device itself.
Analog I/O
First, let’s clarify what “analog I/O” means, because having more analog inputs and outputs can really expand your options. Analog I/O on an audio interface generally includes line inputs and outputs, which are used for connecting line-level audio devices. Line outputs can connect to an external mixer or headphone amplifier to create headphone mixes or route to recording or streaming devices, while line inputs receive audio from playback devices or outboard gear.
You can combine a line output and line input to integrate outboard FX. For example, you could send a signal from your interface’s line output to an outboard compressor, compress the signal, and return it to a line input on the interface.
If you’re dealing with sources that aren’t line level, they’re likely instrument or mic level. These signals typically need a preamp to boost them to line level. An instrument-level signal comes from sources like guitar pickups and needs a DI box or instrument input due to its high impedance. Mic-level signals come from microphones and are lower impedance but require significant amplification from a preamp. This preamp can be built into the interface or used externally between the source and a line input.
The challenge comes when you need more analog I/O than your current interface provides. Rather than constantly upgrading your interface to models with more I/O, digital I/O is the smarter way forward.
ADAT Expansion
For example, the RME Fireface UCX II has 2 mic/line preamps, 2 instrument/line inputs, and 4 line inputs, along with 6 line outputs. These go to a patchbay for flexible use. But when more inputs are required, the optical ADAT connections come into play. ADAT can add an extra 8 input and output channels to an ADAT-compatible device. Connecting an RME 12mic Dante preamp to the ADAT input of the interface, for example, would provide 8 additional preamps, giving a total of 16 analog inputs.
ADAT can also expand outputs beyond built-in connections, which is helpful for complex setups like a 7.1.4 system that requires 12 output channels. An external 8-channel DA converter connected via ADAT can achieve this, and with RME interfaces, you also get the benefit of features like delay and room EQ on each channel.
One challenge with ADAT is that most setups only have one ADAT input and output, which can mean switching connections if you have multiple devices. An RME Digiface USB can act as an ADAT switcher, allowing all ADAT devices to be connected and selectable via preset.
MADI for Larger Setups
When more than 8 or 16 channels are needed, MADI is a powerful alternative, supporting up to 64 input and output channels. Unlike ADAT’s point-to-point nature, MADI can be used in a ring topology to connect multiple devices and create a flexible network of audio routing.
With MADI, you could connect an RME UFX III and several 16-channel converters like the M-1620 Pro, achieving up to 64 channels of analog I/O. These converters may also have additional digital I/O options, such as ADAT, that can be integrated through MADI.
Dante and AVB: Modern Digital Protocols
ADAT and MADI are longstanding standards, but newer protocols like Dante and AVB leverage network infrastructure, allowing audio to be transmitted over standard Ethernet. With Dante, for instance, devices connect to a network switch and can be routed with software, providing a flexible and scalable system for studios, live sound, and corporate AV.
I hope this gives you insight into how different digital audio protocols can expand your setup beyond what’s possible with just analog I/O. Learning about ADAT, MADI, Dante, and AVB can help future-proof your studio and offer a flexible approach as your needs change over time. Stay tuned for more details on using these protocols in various scenarios.