
Every year, Mix contributors Rich Tozzoli, Mike Dwyer and Bruce MacPherson decamp to St. John, USVI, and temporarily turn a house into a studio where they record TV cues while also testing new equipment and software, resulting in a bevy of Mix Real-World Reviews written in a unique part of the real world.
USVI (May 14, 2024)—Universal Audio‘s OX Stomp Dynamic Speaker Emulator is just that: a speaker cabinet “amp-in-a-box” in a compact pedal form.

Basically, as the company website aptly notes, it’s a “studio full of vintage and modern cabs and microphones,” featuring 22 cabinets, six mics and some cool effects, including 1176-style compression, EQ, modulation, and stereo delay.
Settings can be quickly adjusted using the controls on top—Room, Speaker Drive, Output, Mic selection/Level for two mics, or a Rig selector with six choices of setups. The unit also has USB connectivity for updates from UA. Even better, Bluetooth connectivity allows you to go deep into the UAFX control app for iOS and Android, featuring more than 100 custom rigs, or the choice to dial in your own.
It’s important to note how Stomp differs from UA’s OX Amp Top Box, which I do own and use. The main difference is that OX Amp, which is an attenuator, is for plugging your heads or amps into—in other words, it’s a reactive load box that “sees” OX as a speaker.
With Stomp, you do not plug your heads into it (unless you have a dedicated Line Out); you use it directly with guitar pedals (line-level sources). You can also use it as I do, replacing cabinets in guitar FX/ process boxes such as Line 6 Helix/Stomp/Pod or any of the other options from the likes of Boss, Fender, TC Electronic or Kemper. You could also plug any of the other UAFX Guitar pedals into it. But if you want to plug your heads in, you will first need a load box, which then could feed the pedal.
I dig the choice of cabinets and mics, ranging from a 1×10 Black Cha (Fender Super Champ) to a 4×12 Mesa Boogie Recto Large with Celestion Vintage 30s). My favorite mics were the Ribbon 121 and Condenser 67, combined with Ribbon stereo for the room. I like that OX Stomp has true stereo input and output, which lets me do things like put the amp/mics on the left and pan the room sound to the right.
Already having a handful of cabinet simulators in my studio, I can’t say enough good things about the tight, punchy, nasty, dimensional sounds this little f)#$er delivers. The ability to tweak OX Stomp quickly is a tone shaper’s dream. Without a doubt, this microphone and speaker emulator packs a ton of sonic power in a small package.