Can You Use Two Audio Interfaces at Once? (Answered)

By Bob •  Updated: 05/24/21 •  5 min read

There comes the point while home recording where you might need a few more inputs to, let’s say, record drums and track guitar at the same time. We are talking 8 or more inputs.

But the problem is you don’t have enough inputs to do that.

We’ve solved the problem.

Can you use two audio interfaces at once?

The short answer is yes. You can use two or more audio interfaces at once!

But there are a few essential things to know before doing so. 

How to connect two audio interfaces together?

There are a few of ways to do this; the first is by connecting the devices to each other.


1. Connect two audio interfaces together using a SPDIF cable?

The best way to connect two audio interfaces together is with a SPDIF cable.

A digital signal (synced by the same clock) can be sent from one interface and into another, allowing you to send signals in both directions at once.

This also means that if your headphone output on Interface B is activated it will automatically mute Interface A’s line-in input for easy connection between different devices without changing any settings!

2. Plug interface into one another

Connect one audio interface to the other using an optical cable.

Connect one audio interface to the computer using a USB cable.

Connect another audio interface to that same USB connection with an optical cable.

Plugin both interfaces so they work correctly and can be used interchangeably without losing signal quality or power levels between them.

Once connected, use the appropriate number of channels on each device for what you need it for For example, if you are tracking drums, kick, snare, two overheads or vocals and guitars, etc.

The other way to connect multiple interfaces is to do it via computer software.

3. Connect interfaces via computer software

On a Mac, you will go to audio midi set up, click the + on the bottom left, and create an aggregate device.

You will then select both audio interfaces connected to the computer from the menu and click ok.

Double click the name “aggregate device” and rename it so that you know it’s the multiple interfaces we just created.

When you open your recording software, go to the playback engine, for example, and find the new device you just created.

On a PC, you will go to the device tab on your midi settings in windows sound manager or control panel.

Suppose you are using an M-Audio interface with their drivers installed. In that case, it should come up as a BRC (Berkley Research Computer) audio card when selecting what devices to add together for aggregate use.

When adding multiple interfaces from different manufacturers, such as PreSonus Audiobox 1818VSL and MOTU Audio Express 128c, we recommend verifying that they have compatible driver software before making them work as one unit.

To do this: open “Device Manager” in Windows; find each interface where it is listed under “Sound Devices”; right-click each interface and choose “Update Driver Software” to check for updates; if a newer driver is available, follow the prompts to install it.

How many audio interfaces can I use together?

You can link up several audio interfaces together to achieve the desired number of inputs and outputs.

Having more inputs is ideal for recording drums.

After drums have been recorded, I think 2-4 inputs are enough tracks for recording the rest of the tracks.

The one downside to using a lot of inputs is that the system can become very complex.

It’s hard to know what you are looking at when all those channels and buses start flashing in front of your eyes.

The other drawback with more than four or five inputs is latency, which worsens as more tracks are added.

I find it’s best to keep the number of simultaneous inputs below six unless essential for whatever project you’re working on. Still, any less than two seems like too little!

How do I connect multiple headphones to audio interface?

Suppose you have two audio interfaces connected to the monitor and outputs sound from your DAW (digital audio workstation).

In that case, there may be a way to simultaneously connect both sets of headphones.

Check with the manufacturers for more details on how they’ve designed their interface.

Your operating system has settings that are only accessible through editing files either via command line or by using third-party software like Audio MIDI Setup for Macs or Device Manager in Windows PC’s Control Panel.

You can also download free programs called ASIO drivers, which will allow you to use multiple inputs and outputs at once without installing any additional hardware drivers.

Still, these might not work correctly with all DAWs, so beware before downloading them unnecessarily.

Alternatively, you can use a headphone splitter cable to send the signal from your DAW into two separate headphones or a headphone amp.

This will only work if both sets of headphones are taken off one side of the audio device and plugged in on the other so that they’re not using crosstalk or feedback loops and eliminating any chance of ground loop issues with cables.

One thing to consider is whether all channels should be routed through one set of ears while monitoring at once or split between two different people working separately–this may depend heavily on what sort of music production you’re doing!


Whether it is for an audio recording or live sound mixing, you can connect multiple interfaces together.

Suppose you have several different microphones and instruments in the same room and must record all at once. In that case, this allows your interface to handle that task with no problem.

You can also use one interface as a master controller if you use more than two separate devices.

Consider how your needs will change depending on what type of work you’ll be doing so that you buy the right equipment for those purposes.