How To Increase Inputs On Your Audio Interface

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Focusrite Scarlett audio interface. Used for DAW's.

When people first get into music production, one of the first investments they’ll make is in a DAW (digital audio workstation) – this means they will buy an audio interface, some software, and some monitors.

In my case, I bought an MBox 2 Pro Factory with ProTools LE 7 over 10 years ago. It’s a great way to start, and today it’s significantly cheaper to pick something up that is newer and better. There’s also plenty of resources out there to learn what you need to know.

If my memory serves me correct, I paid around $700-$800 for my MBox 2 and the software which came with it. That was brand new. Today you can get something similar or better for half the price. One comparable interface today is the Focusrite Scarlett 6i6, which is only $359.

However, you may find it won’t take long before you’re trying to figure out how to expand the number of simultaneous inputs you have. Especially if you are trying to record drums, record a band live off the floor, or use multiple microphones on the same source to blend and shape your tone.


Spencer making a frustrated face extra holding XLR and TRS cables in his hand while all his DAW channels are all used up behind him.
Need. More. Inputs….

I got the idea for this post because I’ve always wanted to increase the number of inputs for my DAW. However, I was never able to do it because it always seemed like I was going to have to spend thousands of dollars in upgrades to do it.

I recently started over with my research, and I am kicking myself because I can’t believe I didn’t figure this out a long time ago – and it’s dead simple.

In other words, this is the post I wish I had found a long time ago…

This post is going to cover two things:

  1. Two ways you can increase the number of simultaneous inputs on your DAW.
  2. If you are in the market for your first DAW (or replacing your old DAW), how to plan ahead. This way when the time comes, you can increase the number of simultaneous inputs on your DAW quickly and easily while minimizing your expenses.

Lastly, if it interests you gear geeks, I have a fairly comprehensive list of my gear you can check out.

Increasing the number of simultaneous inputs on your DAW

There are numerous ways you can do this and I won’t be able to accurately cover all the possibilities. Frankly, some methods of doing this can be highly dependent on your audio interface and the software you use. So there’s no sense in trying to cover all the different software and devices.

I will only focus on two ways that will likely have the greatest use to most people while being less dependent on specific audio interfaces and software.

1. Create An Aggregate Device To Increase Inputs (Mac Only)

Screenshot of Macintosh Audio Devices window when setting up and aggregate device.

If your DAW is Mac based, then one work around is to create an aggregate device. In the most basic sense, this allows you to combine two audio interfaces so that your Mac sees them as a single device.

Unfortunately, it is not quite as simple as plugging both devices into my firewire ports on my Mac. But it is pretty close.

Creating an aggregate device is one way to “trick” ProTools into thinking you are using one audio interface. In my case, this would allow me to combine the 4 inputs on my MBox with the 8 inputs on my Digi 003 – giving me a total of 12 inputs.

This is especially useful for older ProTools LE systems such as mine. These systems will only communicate with one audio interface.

A Known Catch Using Aggregate Devices

However, I did find a catch. My Digi 003 can not be used as an aggregate device. Despite my research telling me this, I thought I would try it anyways. Sure enough… no dice. The Digi 003 will not be an option when combining devices. So if you are running a Digi 003 or 002 series, you’re probably out of luck. But who knows? It’s not hard to do, so try it anyways.

That being said, if you have two or more audio interfaces that don’t have an optical output (see next method), such as two MBoxes, then it is definitely worth exploring. It should work just fine in most cases.

So for me, creating an aggregate device using my MBox and my Digi 003 Rack Plus was not an option. But it could be for you.

Other useful links on aggregate devices:

2. Use ADAT Lightpipe To Increase Audio Interface Inputs

Focusrite Scarlett 18i8 - rear view.
Focusrite Scarlett 18i8 rear view with Optical Input Circled

ADAT Lightpipe is a standard for transferring digital audio between equipment. This is the method that will work for almost anyone, as long as you have an optical input on your audio interface. You will be able to add up to 8 channels of digital audio inputs to your DAW.

I always thought ADAT was old technology used to hook up old gear like digital tape machines. Wrong.

In my case, my MBox 2 Pro does not have an optical input or output, therefore I cannot do this with the gear I have presently. However my Digi 003 Rack Plus does. So, for a relatively minimal investment, I can expand my system to 16 inputs, and you can do something similar.

How To Hook Up ADAT Lightpipe To Your Audio Interface

The video below is an older video, so he’s using some older gear and software. However, the only thing that will likely vary to any degree is how you set up the two devices to sync together. That will be specific to your DAW software. In this case he is using an older version of Pro Tools LE. Otherwise, it’s probably a lot easier than you thought.

There are other videos out there if this isn’t your specific DAW software. Just search for ADAT and your DAW software. You may also need to include your audio interface (or a similar one).

Planning For Future Expansion With Your Audio Interface

So, you are looking at getting your first audio interface or you are looking to upgrade your old one. If I were to give you one piece of advice, it is this:

Make sure your new device has an optical connection for ADAT

ADAT will be the easiest and cheapest way to expand up to 8 additional inputs in the future, should you choose to do so.

Not everyone runs a Mac and not every device can be used as an aggregate device on a Mac. In my opinion, setting up an aggregate device is kind of a “hacky” way of doing this.

However, ensuring you have ADAT on your new audio interface will ensure your DAW can be expanded using reliable, industry standard methods.

In my situation, purchasing an 8 channel preamp with ADAT now gives me up to 16 inputs – and I can do it for as little as $300. If you have a 4 input DAW with ADAT, you can expand up to 12 inputs for your DAW.

The number of inputs your DAW can potentially have will depend on your audio interface, and what you decide to expand it with. However, I think you will have a hard time getting up past 16 inputs without completely upgrading your whole system – and that can be big money.

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