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How to Choose an Ultra-Portable USB Audio Mixer

This article compares a range of sub-$100, sub-compact mixers that can help you capture top-quality audio at events where you don't need bulkier, more expensive mixers with more inputs than you may need.

Many times when we’re producing recorded or streaming video for an event, we may have a dedicated tech, often from an in-house A/V crew, handling the live audio. We might just need to get a line from the house audio feed to our stream, but often it’s not so simple. It’s helpful if we can adjust those levels, and maybe also add a room mic for audience ambience as well. 

In these cases, we probably don't need to lug a big 16-channel mixer to the venue, but it would be nice to have a tiny little USB audio mixer that can interface with any number of recording and streaming solutions and handle these two tasks for us.

I’ve been searching for such a mixer, and have found the solutions more numerous and varied than I expected. In addition to features common to most or all of them, each one seem to offer something unique. So I gathered them up for this overview.

To be included here, a mixer had to be available for $100 or less, and include several key features:

  • USB-powered and delivering USB audio to a computer. No external wall warts or AC power supply needed.
  • A microphone input, with some basic EQ and the ability to adjust gain and level.
  • Preferred bur not required: a low-pass filter.
  • A line input, with the ability to adjust EQ and level.
  • Master audio level adjustment for USB output.
  • Independent headphone level.

What you won’t find, in most cases, are nice long faders to make it easy to keep your finger on the level and adjust it as needed. You probably won’t need it, because riding those levels is someone else’s job, right? I did find one with a fader on the mic input and that could be handy for audience questions, etc.

You won’t find “solo” buttons for monitoring various inputs independently. Because these mixers have only 2, 3, 4 inputs, you shouldn’t get lost. Nor will you find any decent metering, unfortunately. Aside from an LED to show there is a signal, or red for a channel clipping, you are relying on someone else to manage the audio, and whatever you're feeding the audio to for more elaborate metering.

But what you do find is a diversity of mic/line input options, after that first mic input. Some use RCA for line level, others use 1/4", or combo XLR-1/4" inputs, with the capability of handling instrument impedance as well as line level and mic level. There was one nice-looking mixer with XLR outs and nice metering. There was another with bluetooth in.

A few mixers seemed to offer the ability to monitor the USB audio back out. But it really looks as if these are designed to also include playback of a computer backing track into the mixer and then use the main outputs to feed the room. It doesn’t appear to be really designed to monitor a “wet” feed of what you’re sending to the computer because the possibility of creating a feedback loop is very high. So I’d recommend leaving audio monitoring of the USB audio to some other headphone output from the computer or other device.

Let’s look at the selection of tools.

Muslady SM-33

This tiny little mixer is about as basic as they come, with a Mic and a mono/stereo input. No EQ, no high-pass, no panning, no gain--just in to out with adjustment of each of the two signals compared to each other. This may be all you need.

Pyle 2-Channel Mixer

This one looks a little different, with the knobs offset and not the typical vertical alignment you see in mixers. XLR in, Stereo RCA in, Master out, Headphone out. This one has a USB assign to Line, and if you were using this for live streaming, that button looks to get you in a whole lot of feedback real quick. So I recommend avoiding those buttons completely for recording/streaming uses.

The next few we’ll talk about look pretty similar, as is the case with a lot of manufacturing these days. Look closer, though, and key differences appear.

Ammoon AGM02

This one has XLR on Channel 1, with gain, 2-band EQ, panning, channel level, and a peaking LED. Nice. Channel 2 is unique: XLR again, so it’s mic/line-capable, but with a button for high or low gain. Just two channels. Not even stereo.

Another item to note is an 1/8" mic input as well for channel 1, making it convenient for consumer-grade mics to plug in. You’ll see this a lot going forward.

The fat main mix knob is nice, and a separate headphone knob. Easy to know the difference by touch. If this had a second stereo set, in addition to the two mic/line inputs, I think it would be the one I wanted.

Pyle 3-channel Mixer with Bluetooth

This Pyle model is billed as a 3-channel mixer, but it really supports 5 channels. Pyle has a nearly identical model that they do call a 5-channel mixer, so I don't understand why they call this one a 3.

It has XLR on Channel 1, with gain, 2-band EQ, panning, channel level and a peaking LED. Nice.

Channel 2/3 is stereo RCA with no note of mono on left, but there’s a pan and EQ control so you can probably send the signal where you need it.

The "2-Track" is a second stereo RCA input, but with no level adjustment in the mixer. You can swap this out with Bluetooth in. So you need to control the level from the external device.

Another 1/8" mic input as well for channel 1, making it convenient for consumer-grade mics to plug in. The fat main mix knob is nice, as is a separate headphone knob. It’s easy to know the difference by touch.

Pyle PAD20MXU 5-channel Mixer

This one actually has a model number on the unit! It’s nearly identical to the previous Pyle 3-channel mixer discussed above, except no bluetooth, and no buttons to assign the USB audio to the headphones. There’s a button to assign the USB audio to line in, but it doesn’t indicate where USB audio goes when that button is not pushed. This one also says “recharge” at the top--there’s a tiny internal battery, if you needed that.

Behringer Xenyx 302USB 5-Input Mixer

I bet you’re starting to see a trend now. This Behringer model is very similar to the Pyle 3-channel mixer, except there’s no power switch or bluetooth, but I dare say a nicer-looking design than the Pyle. It matches the rest of Behringer’s product line and it just looks nice.

It has XLR on Channel 1, with gain, 2-band EQ, panning, channel level, and a peaking LED.

Channel 2/3 is stereo RCA with no note of mono on left, but there are pan and EQ controls so you can probably send the signal where you need it.

Then “2-Track” is a second stereo RCA input, but with no level adjustment in the mixer. You can send just this input to the headphones, like if you wanted to cue a track for playback before adding it to the mix.

Related Articles
This article is designed to help you avoid some of the many pitfalls that you can fall into when doing audio mixing for live production.
Live audio is challenging. Unlike many of the issues that arise on the video side of the equation, none of the problems that affect audio quality—RF interference, feedback, ground loop hum, hiss, over-modulation—can be seen. All of these challenges take a knowledge and understanding of the problem to assess and fix them properly. On live productions, more often than not, the time to fix audio issues is as soon as you hear them starting to happen.