Church Production

Review: Radial Engineering SB-5 Laptop DI

What to do with noisy consumer-grade equipment? Radial Engineering introduces a 'must have' tool for church sound techs.

By Mike Sessler
September 19, 2013 7:16 pm EST

Topics: Audio,
Tags: audio, cable, laptop, mixing,

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Connecting consumer-grade equipment to a professional sound system is always a pain. It happens to all of us, though, so we had better come up with some plans on how to handle it. Sure, you can get a 1/8-inch to dual 1/4-inch cable made, and that might work OK when the laptop, iPhone or iPad is at FOH. But what about those times when a visiting speaker wants to run some audio from his laptop on stage? Or the music director decides this would be a great week to do an all iPad band? Or you just need to run a click out of a smartphone on the drum riser?

We can all come up with janky solutions that will work, but as often as not, you have problems with buzz, noise and hum. And let’s be honest, it doesn’t look professional. Enter one of the newest creations from those smart Canadians at Radial Engineering, the StageBug SB-5 Laptop DI. Laptop DI’s aren’t new—in fact Radial makes others, the ProAV1 and ProAV2—but this has a few features that make it unique.

Thoughtful design

First, the StageBug SB-5 comes hardwired with a five-foot cable terminated with a 1/8-inch plug that conveniently stores wrapped up around some heavy-duty cleats on the side of the device. I was glad to see the 1/8-inch plug was small enough to plug into my iPhone without removing the case. It has both a set of stereo, balanced TRS outputs and a summed mono balanced output on a single XLR. A –15 dB pad drops hot inputs to a manageable level, and a ground lift switch ensures you won’t have any ground loop issues.

Like all Radial units, the housing is heavy-gauge steel, and it’s likely it would survive being run over by the tour bus. Inside that housing is a set of custom-wound transformers that drop the impedance and balance the signal. Radial claims that cable runs of up to 300 feet are possible with the SB-5, something I didn’t test, but have no trouble believing. We have quite a few Radial DIs on our stage, and I’ve never had any issues with them.

I really do like the fact that the 1/8-inch cable is hardwired to the unit. Those things can be incredibly hard to find during a sound check when you’re scrambling to find a way to hook up a rogue device. And invariably, one side doesn’t work, which sends you looking for another. The fact that it’s permanently attached to the box means you’ll never be without it.

Sound quality

Radial has a well-deserved reputation for high sonic quality—and the SB-5 is no exception. Before doing any real listening, I hooked up my laptop to my studio Mac Mini using the SB-5. I ran the 1/4-inch outputs into my Focusrite Saffire interface, using the front mic inputs (as the SB-5 outputs mic level). Using SMAART, I set the laptop to output pink noise and looked at the result on the Mini. I expected to see a pretty flat trace with some roll off at the low and high end. What I saw was a laser-flat trace that was flat from 20 Hz to 20,000 Hz. I honestly didn’t think I would see that kind of frequency response out of a headphone jack.

I switched over to some music to listen to, and was equally impressed with the sound. The Eagles’ Hotel California sounded as haunting as ever. The low end was very tight and the cymbals sounded just like they should.

I was going to compare the output of the laptop running directly into the interface, but decided not to. Given that the frequency response was so flat with the SB-5 in the loop, it’s clearly not doing anything adverse to the signal.


At a street price of about $100, the SB-5 is certainly more expensive than a cheap 1/8-inch to dual 1/4-inch cable. But you’d never get a 100-feet run out of such a cable, let alone 300 feet. And the ability to lift the ground might be the thing that saves the day. The SB-5 is very small, roughly a third smaller than the company’s standard-sized DIs; so it will easily fit in a backpack, workbox or hard case. This is the kind of tool that just about any traveling audio guy should have, and it’s equally useful for the church environment. In fact, even though they gave me this unit for the review, I’m going to order a few more to have around the church—I can see that many uses for it.


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Using laptop audio a LOT in my mixing settings, this looks like it would be a great addition to my toolbag. Even the proper cables are not 100% trustworthy and more than once I've had to dig into my misc. cables drawers to find an alternative to the 1/8" - 1/4" that I plugged in that all of a sudden no longer works.

By Dave Lenehan | October 09, 2013

"It has both a set of stereo, balanced TRS outputs and a summed mono balanced output on a single XLR." "You will need two TRS X XLR cables or adaptors to connect to most snakes." If they can put an XLR connector in the box for the mono output, then they can put two XLR connectors in the box for the stereo output. It would be nice if I could just buy the device and plug it in without having to make up "janky" specialty cables first... "I really do like the fact that the 1/8-inch cable is hardwired to the unit... And invariably, one side doesn’t work... The fact that it’s permanently attached to the box means you’ll never be without it." Until one side doesn't work (which won't take long considering how I see most people treat their equipment), then I'm hosed because it will happen 5-minutes before a service, and I won't have time to open the box and replace the cable (I know, the alternative is a 1/8" stereo jack that will eventually break as well, and under the same conditions. I'm just sayin').

By Phil Haney | September 25, 2013

Reread the review a little closer. The dual TRS outputs are balanced and at mic level which is the same as XLR. You will need two TRS X XLR cables or adaptors to connect to most snakes.

By George | September 15, 2013

Useless. Stereo TRS out? You need stereo XLR outs if you're going to run to the main board without adding 2 more direct boxes.

By Richard | September 14, 2013