Radial USB-Pro 2-channel Active Instrument Direct Box Reviews

Best di box stereo. Can't beat this price really good.

Aside from the quality and sound of this unit, which is not in dispute; It is awesome. Many might be put off by the USB B2 input.
There are several options here.
A. USB-B to USB-C 3.2 cable, readily available (fairly sure this provides more power & data than most video monitors require)
B. USB-C to USB-A converter, using a USB-A to B cable. Both are readily available and provide enough power to operate.
C. USB-A to USB-C cable (for USB-A equipped computer outputs.) This works equally well. Dumb to list I know but still should at least be mentioned.


The moral of the story is don't fear what ports are available on your computer, as long as you have a USB port of any kind.

Caveat: USB C and Thunderbolt are not the same thing, (Thunderbolt 3 ports are typically C compatible to operate USB C devices, but not the other way around) but a USB 3 C / thunderbolt 3 to USB-B cable should work in a thunderbolt port. I have not tried that specific config, so I cannot speak to that. The USB port on the unit is a USB type B spec. It is probable that a thunderbolt 3 to usb B cable should work, just make sure you order from somewhere that has a generous return policy for the cable.

If your motherboard has a PCIE 6-pin power connector to provide extra power to your PCIE and USB bus, you should get close to 60W at your USB port outputs. I think standard power without the added power input on a mobo is close to 27W.

Power requirements are listed on the Radial website as 500mA max, which is easily met by a standard USB 1.1 type bus.

My only beef with this thing is that the USB-B port is not on the same end as the XLR connectors, which would make for a cleaner look and easier wiring for my personal situation. Probably configured this way for noise isolation, but I am just guessing.

5 star unit. Oh yeah, do not use in the rain lol...

I Use mainstage for some keyboard sounds in live gigs. This makes setup simpler and more professional looking. I no longer need an interface or a separate DI. All goes into the computer and out the DI. On top of It being simpler, less equipment, and more professional looking.... this box just sounds better. Ive tried every other output method: Portable Audio Interfaces, 1/8inch out to TRS, etc.... This just sounds significantly better.
Its obvious that a DI at this price point would beat out portable audio interfaces or cheapo 1/8inch cables, but I still was genuinely surprised at how much more full everything sounded.

This product is a great solution and alternative to analog audio connections. The DI is essentially plug & play and offers a high quality sound product without all the hums and and static that comes with traditional analog audio equipment.

Highly recommend this for anyone considering making the jump to digital for playback function, or keyboard software.

Our church is setting up a USB Nased Midi Keyboard Rig, and this is our interface to the sound system. Set up was stupid simple and sound quality and performance is impecible. THank you again Sweetwater for providing another great piece of gear.

Works perfect to connect my Macbook Pro to a sound system for running tracks. The sound is 1000% better than coming out of the headphone jack into a standard direct box. If you're gonna do it, do it right. This is a solid DI that is the right tool for the job.

If you need a way to get digital audio into analog inputs on a mixer, or whatever, this is the answer. Works exactly as advertised and the sound quality is outstanding. I've used it with both Windows and Mac laptops. I have 2 other Radial DI boxes and they are all built like tanks. I highly recommend this product.

I am so glad I found this affordable solution. It is a simple and direct way to send backing tracks and audio over USB to the sound board. Monitoring and mono-sum options are nice and simple. This removes the clutter from my live setup and allows me nice local control as well.

My church has been running outdoor services and the need for before/after service music was a challenge. At first we tried using a 1/8" TRS cable to XLR that we found on another site but this left lots of strange audio issues (certain stereo sounds came out distorted). To improve the sound quality I used a USB audio interface output to 1/4" then two direct boxes to send these as XLR back to the mixer. Overall this worked but I really wanted to streamline this into a simpler setup and not bring in my expensive audio interface.

Searching around I found this Radial USB interface and at first thought, it wasn't that important but after using it more, I realized a few things. The sum to mono sounds pretty good compared to other methods, since we're using this in a live setting, everything is going mono for the house. Mono doesn't sound great in the headphones but this does leave the quality pretty close to the original sound without any issues. The interface does support stereo as well, there's a switch to flip between mono and stereo.

The interface also has a headphone output for monitoring, super handy and this allows you to "solo" the laptop before unmuting to make sure it's correct. I know you can do this from the mixing console but we are running a XR18 headless mixer sitting 30 feet away, so this is my way to checking the sound before it's live. Along with the headphone output is the level output, for me on the XR18 mixer, I have this set to about 10 o'clock and it's plenty loud.

Another feature of this interface is using it with Ableton Live, where you need to have backing tracks to play along with on the stage. For a few praise teams a popular interface is the Loopcommunity Track Rig, this allows USB to send eight output XLR's for various channels. While the Radil is only two channels, it's still allows you to bring your laptop to the event and send output with a small device instead of using an entire rack device. Yes, you can still use any audio interface, output to a direct box, this just seems simpler and less to deal with doing a live performance.

Just to note, this does not come with any USB cables, I'm using a simple USB cable and you don't need anything special. I do recommend something longer, as if you drop this interface, it's like a small brick and will most likely pull your laptop off the table.

One last thing, I reached out to Radial Engineering twice for support questions and both cases they responded within 24 hours. I really try to support made in USA/Canada engineering to keep this support chain going along.

I have found that trying to use the audio headphone jack out on a laptop (or iPad) at a live show doesn't always work — and it's super embarrassing when that happens (and it happened to me). Computer audio through 1/8 inch jacks are strange beasts, and often don't cooperate with DAW's and mixing software. This box was like a gift from the heavens. You plug in your laptop (or your iPad with an adapter) via USB (the printer cable end) and then go XLR out to the stage box or console and voila! You're ready to perform. I have also used (when I didn't carry the right cables) the headphone out jack (1/8 inch) and patched in that way (1/8 inch to dual XLR cable, I think). For DJ and mixing duties (for hooking this unit up to a Pioneer mixer, for instance), make sure you have a set of XLR female to RCA male (stereo cable) so you can patch into that type of unit. I didn't even know this device existed until I ran a search for solutions; once I saw it, I bought it from Sweetwater. Radial makes great products (I have others) and the build quality is like a tank. Great purchase!

I do movie/concerts with symphony orchestras. Part of my responsibility is making sure the synths for each show are functional for the player and the sound system. I carry one of these direct boxes for each synth. They work. Every time. Period. Rock solid and great sound. I would definitely purchase these again if I have a need.

This is a great product. All I wanted was a way to rum mu laptop tracks via USB without any messing around. Just unpack, plug in, turn up the level and play. Thats it!

This is my first Radial purchase and am totally sold on this brand now.

Expensive for sure, but TOTALLY worth the money. I purchased this to run backing tracks live from my Mac and this works great for that purpose. My rig previously required an audio interface connected to my laptop, 2 instrument cables and 2 DI boxes to be able to run the tracks. Now all I need is this ONE piece of gear connected my laptop and done. A lot less gear to carry around and less risk of cables failing or interface dying etc. This is a solid product and is built like a tank! It's got some good weight to it and the padding on the underside of the DI box greatly minimizes movement on surfaces. Just a solid and great product! Don't hesitate to buy!

I needed a way to get audio out of my computer and into my mixing board, and using the headphone jack wasn't cutting it. The Radial USB-Pro was the solution, taking USB audio from the computer and converting to analog XLR output. The sound quality is excellent and the output level control is invaluable.

I used the ground lift to kill some noise. There are also isolating transformers that you can engage. I think these are primarily useful if the board provides 48V phantom power, which you don't want to inject into the USB and DAC circuitry; the isolating transformers would preserve the signal but not transfer the phantom power.

This thing is rock solid and well built. Read the instruction manual and use the proper procedure to set things up.

This is my second piece of Radial gear (I use the ProDI passive direct interface box). The consistently high quality build and operation of both devices is impressive. Radial's tech support is responsive and helpful.

Plug and Play. No drivers needed (atleast on a mac osx).

I have an imac that I would send out sound to our board from the headphone jack, and then unplug during the week to plug in computer speakers. the constant unplugging caused the jack to start giving me issues. this lets me send the L/R XLR to the main mix. and run a splitter from the headphone out to my computer speakers (when I use them) and my headphones during the week, without having to constantly unplug.
Works Great! What I like the most is still being able to turn the volume up and down using the keyboard shortkeys on a mac.

This, like other Radial DI boxes, is a must-have piece of equipment. It's dead simple; since it's a USB compliant audio device, just plug into whatever computer your using via USB cable and you're done (you may need to pick the appropriate audio device if you have more than one). You get pristine sound, and as much gain control as you could possibly need. We have two: one for split tracking (background instruments/click track) and another for a synth laptop running Omnisphere. Couldn't be happier.

I like gear that is built to last, and I like not having to wrestle with driver/configuration issues and other loathsome, computer-related hindrances. The Radial USB-Pro ticks those two boxes. It is built like a tank and it works exactly as advertised, period. Simply connect it to a USB 2.0/3.0 port, kick back and wait sixty or so seconds. It is literally that quick and effortless.

Radial states on their website that the included headphone output is for testing, not for listening to music. I would actually argue to the contrary; to my ears, it is as clean as it is LOUD. To discern any noticeable hiss, I would have to bring the volume knob well beyond the twelve-o-clock position, and by that point I'd have done irreparable damage to my hearing. Make use of it, but consider yourself warned. (Note that the knob does provide plenty of tension, as it should.)

Of course, it'd be nice to have a USB cable included with the product, and I also would have preferred the digital input to be located anywhere else but the front. But overall, I can hardly complain given the sheer level of quality inherent. It is an affordable, indestructible, high-fidelity DAC... If such is what you require, get this without hesitation.

If you need to get audio out of your laptop and into a pro audio system, this DI cannot be beat. Best audio quality I have encountered and built like a tank. Plug and play and your on your way...

It works with both Mac and Windows with barely any set up time. My computer speaker set up is way better than when I used the jack input. This is my second Radial purchase over the years, but I plan on getting a few more in the near future.

As with all of the other Radial products I have used, this USB-Pro does everything with excellence. It has a great quality DAC, it is pure and simple plug & play setup with both Windows & Mac (I've used both), and it provides exceptional an exceptional and clean audio signal into any professional sound reinforcement system. Of course the nearly bulletproof enclosure ensures this unit will outlast just about every other piece of gear in the bag. Ditch the soundcard and 1/8" cable / adapters and go with the USB-Pro for a balanced, stereo signal to the mixing console!

I was impressed by this box…Actually, this was a great help to me, because I needed a solution that would allow me to play a few virtual instruments from my laptop in a live situation… This turned out to be a flawless operation…The manufacturer mentioned that the headphone jack was only for checking the signal, but it does serve as a pretty good headphone jack for monitoring purposes…I'd like to thank my sweet water representative Delvin Wolf and his assistant Heather for their prompt service and insight..

This would be %100 perfect if it was future proofed with a USB C input for basically all newer computers! Radial should update that if they are going to continue calling it a pro model.