Use an Audio Interface Instead of a Mixer or Attenuator

Did you know that you don’t need to fork out money for a mixer?

Erik Engheim
6 min readApr 26, 2024
Example of Audio Interface Scarlett 2i2 Studio (Credit: focusrite.com)
Example of Audio Interface Scarlett 2i2 Studio (Credit: focusrite.com)

The world of music is full of expensive equipment, and the internet will bury you in advice and information. Recently, I forked out a bunch of money on a Yamaha MG06 mixer. Shortly after, I realized that was a total waste of money and overkill. What many of you may not realize is that an Audio Interface is essentially a very minimalist and simple mixer, but which also has an Analog to Digital Converter (ADC).

Yamaha MG06 mixer
Yamaha MG06 mixer

In fact, for what you get, and Audio Interface is extremely versatile and cheap. Allow me to explain why I got a mixer and why it wasn’t needed. Lots of equipment gives signals of the wrong strength, such as guitars, microphones, or synthesizers. That means you might need to amplify that signal or attenuate it to get a line level signal. A line level signal is what comes out of CD players, iPods, mixers and go into amplifiers. It is what your AUX port expects, for instance.

The signal strength from an unpowered microphone, in contrast is very weak and requires pre-amplification before it can go into an amplifier that drives your speakers. Instrument’s level is what you get from electric guitars. That is a lot stronger, but not as strong as line level. While a modular synthesizer built on the Eurorack standard gives a much stronger output signal than line level and thus needs to be attenuated (make weaker).

Eurorack synthesizers are assembled by user using modules (Credit: intellijel.com)
Eurorack synthesizers are assembled by user using modules (Credit: intellijel.com)

A mixer can do all these things. Mixers take signals of different strengths in and have dials to adjust input gains to bring signals of different strengths up to the same level and then mix them together into one signal that you can send out to your amplifier which drives your speakers.

Not all mixers can handle hot signals (high voltage signals such as Eurorack). Typically, more expensive ones will have a button which allows you to set a higher input impedance (allows you to handle higher voltage signals).

My Audio Interface Volt2 from Universal Audio (Credit: www.uaudio.com)
My Audio Interface Volt2 from Universal Audio (Credit: www.uaudio.com)

I do have a Volt2 Audio interface, so I can record a guitar or synth on my computer, but I want to be able to play a synthesizer without powering up my computer. Furthermore, when playing through my computer, I have to do it through GarageBand while pretending to be a guitar.

I wanted a solution which allowed me to work exclusively with my Dreadbox Erebus synthesizer without requiring a computer. That is why I got a Yamaha MG06 mixer. It has a button to specify high impedance input. Except this cost around 138 euro on Thomann online store (they are cheap). I considered first buying an attenuator such as the Dreadbox Utopia. But it costs 99 euro and doesn’t do much besides making a signal weaker. Add less than 40 euro and get a proper mixer seemed smarter to me. A mixer has more varied usage as it can attenuate, amplify and mix signals.

The Dreadbox Erebus synthesizer (Credit: www.dreadbox-fx.com)
The Dreadbox Erebus synthesizer (Credit: www.dreadbox-fx.com)

But it turns out that Audio interfaces has something called Direct Monitoring, which allows you to bypass your computer entirely (digital audio workstation) and send your sound signal straight to your amplifier (or active speakers). Usually, it is a button you push on your Audio Interface. In this mode, your Audio interface essentially work as a mixer. You don’t have to connect it to a computer.

Why didn’t I know this, and why are you unlikely to learn about this as an alternative? This feature is sold as a way to listen to your input without latency instead of going through your Audio software. The feature is not presented as an alternative to a Mixer. Thus, when talking to experts in several Music stores, nobody actually told me about this possibility. They all told me to buy a Mixer. The same advice I got online. Or more specifically, they suggested an attenuator.

But both are bad choices money wise. If you only need one output you can get a high-quality Audio interface such as the Volt1 for a mere 128 euro at Thomann. That is cheaper than the mixer. That only has one audio input, however. But you can get the Volt2 I use for 169 euro. That is just 20 euro more than the mixer and gives you all the following features:

  • Mixer for two input signals which can be microphones, guitars or synthesizers
  • A headphone amplifier
  • Stereo output to speaker amplifier (line level)
  • MIDI input and output ports
  • USB port to allow recording sound to your digital audio workstation running on your computer such as GarageBand, Ableton or Logic Pro.

In other words, you get a lot of features in one package. Seriously, anyone doing anything with sound should get an Audio Interface because they are so useful. For instance, did you know that a USB microphone is made extra expensive because it needs to contain an Analog to Digital transformer?

I never thought about that, but quickly discovered that when buying passive analog microphones you get much better quality microphones for the same price as a USB microphone. To use these you need an Audio Interface. Sure, an Audio Interface plus a Microphone is more expensive than a single USB microphone.

But once you got an Audio Interface, you got so many more options. You suddenly also have a headphone amplifier. You have a mixer, so you can add two microphones if you have two people talking and doing an interview. Should you get into Music, that option is now available.

Let us not even talk about attenuator modules for Eurorack boxes. They are expensive as hell for what you get. But how come an Audio interface can do so much for only a slightly higher price? Volume. Weird geeky stuff selling to a small market will be expensive. Audio Interfaces in contrast, are widely used and sold on volume. Hence, you get a lot of bang for the buck.

When to get a Mixer or Attenuator

If an Audio interface were a full replacement, nobody would sell mixers and attenuators. My Yamaha mixer could mix six inputs, so if I was recording and mixing music from multiple sources it might have been worth it.

Then again, you could just do separate recordings and combine them in your Digital Audio Workstation (DAW).

What about attenuators? If you have multiple signals which need to be treated separately and attenuated, then they can be worth buying. But that is not an issue for me as I have only one synth I want output from.

Besides, many semi modular synths have attenuators. My Behringer Neutron synthesizer which I just got in the mail has an attenuator.

My purpose of writing this article is to show you that you don’t need to get everything when starting to delve into electronic music. If you just get an Audio interface, you already got a lot of useful functionality.

Also, most Synths will give you line out and not a hot Eurorack output signal. The reason I got a Dreadbox Erebus is that it can be unscrewed from its box and placed in an Eurorack. I might never explore Eurorack, but I want to have that option down the line.

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Erik Engheim

Geek dad, living in Oslo, Norway with passion for UX, Julia programming, science, teaching, reading and writing.