Universal Audio OX Review

Universal Audio says its OX amp top box is the first system to accurately emulate speaker drive, breakup, and cone cry. Could it be the ultimate creative tool for guitarists? Rich Tozzoli found out.

With a name like OX, I guess you might expect something sturdy. And that’s exactly what you get with Universal Audio's reactive load box and guitar recording system. The OX Amp Top Box lets you plug in your favorite tube amp and get the sound of a mic’ed up studio cabinet, without actually having to have a studio - or a cabinet. It also takes it quite a bit further than that with built in effects, room sound (with or without carpet!), different mics, speakers cabs and built in WiFi control over it all. Let’s look at a few of the best features of this unit and examine how it works in an actual session.

Start It Up

I must admit, I was still not totally sure what OX was until I got the unit in my hands. Since I work primarily in my home production studio and compose for TV shows mainly on guitar, I was intrigued to see how an ‘amp top box’ could fit my workflow.

Most of my tracking is done either direct into software, through hardware units, or through my heads or amps using a variety of cabinet simulators. Since I tend to prefer the feel of tubes with my instruments, OX immediately had its place in the studio.

With its sturdy 14 lb build and classic yet simple design, OX lets me take my main tube recording head, which is an older Mesa Boogie MK IV and plug it into the back of the unit's speaker jack input with a ¼” speaker cable. It's the only input on the back with a red ring around the input and its aptly labeled FROM AMPLIFIER (thats easy!). After choosing either 4, 8 or 16-ohm operation, you then connect either the coaxial RCA or S/PDIF digital output, or the LINE/MONITOR L/R outputs to your preamp and into your DAW. You can also connect the TO SPEAKER ¼” jack to your speaker cabinet if you should choose to.

But for my purposes, keeping the volume at a lower level, while still being able to plug into my Boogie or other amps, crank it up and feel the finger response of the tubes through a mic’ed up cabinet with room and or/effects is the reason I’m using OX. However, this is not just a load box that lets you plug the head into it and record. It’s got a few tricks up its sleeve.

Quick And Easy

To take OX to the next level of production, you use the OX Software for Mac and iOS, which is available via download from www.uaudio.com/ox/app or from Apple iOS App Store. When using the software, the included presets (over 100) can be edited and stored wirelessly, using OX’s built in Wi-Fi network. Each RIG preset contains an emulated speaker cabinet, speaker mics, room mics for ambience and the ability to add up to four effects at once. These effects, which are applied after the dynamic modeling, include a 4-band EQ, 1176 SE compressor, stereo modulation delay and stereo plate reverb.

The front of OX features five Control Knobs, which are RIG (to choose from 6 presets with 16 different Rig Sets), ROOM (for the mic’ed studio ambience), SPEAKER VOLUME (volume of the guitar speaker connected to OX), LINE OUT (adjusts the level of the LINE/MON outputs) and HEADPHONE (adjusts the levels of the headphone output available on the rear of the unit). It’s important to note the RIG and ROOM don't affect the speaker output, which is the pure analog amp tone.

The Rig Knob

The 6 default presets can be easily accessed from the front panel Rig knob. Rig 1 is a 4X12 GB25 punch cab with Con 67 and Rib 121 Close Mics and stereo Condenser room mic with carpet. Rig 2 is 1X12 Blue J cab, Dyn 57 and Rib 121 close mics and carpeted ribbon stereo room mic. Post Fx on this is a plate reverb. Rig 3 is a 2X12 ACE TOP Cab with a Rib 160 and Con 67 close mic and a condenser mono mic for the room. Rig 4 is a 4X10 BMAN cabinet with a Con 414 and Con 67 close mic, Condenser stereo room mic and a Plate Reverb for FX. Rig 5 is a 1X10 BLACK CHA speaker, Dyn 421 and Con 414 close mics and stereo condenser room mics. Rig 6 is a 2X12 BOUTIQUE D65 cabinet, Con 414 and Con 67 close mics and carpeted condenser stereo mics with Delay & Plate Reverb Post FX. Thats a lot of options with the simple click of a knob. You can of course mix, match and create your own Rigs, which we will get to shortly. But that just gets you warmed up.

The Software

The real power of Ox lies within the software, where you can customize the sound quite a bit. The downloadable app for iPad or software for Mac computers connects via wireless Bluetooth to the OX hardware unit, which in turn allows you to access 17 different speaker cabinets, 6 close mics, 5 room mics and the effects.

The two mics per cabinet can be panned, muted, solo’ed, set off axis and low cut, as well as having the ability to output the level of each to the master outputs (Left/Right). Also, each has the ability to open an EQ page for additional tweaking. The Room mics can also be EQ’ed, and panned, and again the volume will feed the output master. The DAMP button inserts a carpet into the room, which cuts down some of the reflection. There’s also a Speaker Breakup knob for harmonic complexities and the ability to set 50W or 100W Input Level.

The Rigs, which are the entire tone presets, can be altered, saved and assigned to the front panel Rig knob on OX.

In Session

OX is really all about tweaking tone. My first experience using it was on a TV session with Ian Hatton (Bonham/Robert Plant), where were cutting some cool crime/drama tracks that allowed us to dig in to the sounds at our fingertips. The basic setup was Ians pedalboard into the Boogie head, which fed OX. From OX, the Left and Right outputs then fed a pair of Millenia preamp channels, and then off into two channels of Pro Tools HD. I ran the Ox software on my MacBook Pro, which connected to Ox via Bluetooth. Note that currently the software requires iOS 11 for iPad or Mac OS Sierra or High Sierra.

Driving the Boogie head, we used a 4X12 GB 25 THICK Cab with a Dynamic 57 set Off Axis and a Ribbon 121. We set the Input level to 50W, even though Ox is designed to not have to worry about matching 100 or 50 Watt levels. Next, we turned up Speaker Drive, which is set to model newer speakers when set low, then increasingly spongy and broken in as you turn it up. However, neither Ian nor myself felt or heard much of a difference, so we left it up just a bit.

Here’s some of the cool things we found out on our session. You can pan the first mic, which was the Dynamic 57 to the left, and the second (Ribbon 121) to the right, and capture 2 separate mic sounds in your DAW. Then, if you turn the room up and pan it up the middle, an equal amount of room will be in both channels. And I have to say, this room, which is Universal Audio's own, is absolutely superb. In addition, having the option to choose different mics for the room, add or subtract a carpet, or add effects to the room chain is quite useful. Having control over this allowed me to mix and match the tones and levels later when it came time to mix.

First, Ian plugged in one of his custom Strats with a set of Seymour Duncan JB pickups, and we were both highly impressed, and just as important, inspired by the sound. Without thought, which is the best way in my opinion to capture magic, he laid down some great tracks. Taking it a step further, I plugged a bass into the same signal path, split from a good DI, and captured a nice edgy distorted bass sound, this time using a 4x10 cab (like a Bassman) and even a bit of room sound with an 1176 compressor on it. Like the guitar tones, it was punchy, warm and full of character.

Here’s some of the full mix from that session with multiple guitar parts and the bass through OX. Note that I’ve added additional plates and delays to the sound.

Guitars and bass isolated

I have come to use OX and its sonic options in a number of ways. One of them is to take the sound of the two microphones (again with my Boogie head) and pan them together hard left, which I then control the single channel balance of using the two microphone volume controls on OX itself.

Then I take the room sound and pan that hard right, which delivers me an isolated channel of room. On top of that, I add some 1176 style compression to the room sound.

In addition, I included some plate reverb in the 2 microphones. Overall, this gives me a nice thick guitar sound on the left, with some distance and depth.

When you add them together, I have the 2 guitar mics panned about 11 O’clock in Pro Tools on a single channel, previously blended in the OX software. Then, I take the room sound and pan it hard right. Together, they sound like - well - a mic’ed up amp in a good live room!

Plug And Play

To change up my guitar sounds even more, I simply plug in any of the other heads I have, such as the Orange Micro Terror or Micro Dark. It lets me almost think of my amps as software modules, except for the fact that they are real tube heads that get unique sounds. Not limited to just heads, you can also plug in any amp that lets you unplug the speaker, such as your favorite Fender Deluxe Reverb or whatever you like to play through. Again, this lets you get your amp sound, crank it up, and not have to peel the paint off the walls.

Simply put, the OX reactive load box is all about the quality and detail of the Universal Audio modeling, the speakers, microphones, effects, room tone and finally, how it reacts with the player. I find OX to be an invaluable tool in my studio production arsenal. It takes the simple premise of a speaker cabinet simulator and takes it to a much higher level offering a sonic flexibility that frankly, no other product yet has.

Price: $1299

Pros: Excellent sounding cabinet emulations, sonically flexible, room sound is superb, good choice of mics with ability to create separate outputs, bluetooth software takes it to another level.

Cons: Mac only for WiFi control, could use some bass cabinets, pricey.

Web: https://www.uaudio.com/hardware/ox.html

Learn more about guitar production: https://ask.audio/academy?nleloc=category/audio/topic/guitarproduction

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"Grammy-nominated Producer/mixer/engineer/composer Rich Tozzoli has worked with such artists as Al DiMeola, Ace Frehley and more. Also specializing in 5.1 Surround Sound production, he has mixed DVD’s and/or HD Television broadcasts for the likes of David Bowie, Hall & Oates and Blue Oyster Cult. Also a lifelong guitarist, his music c..." Read More


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