Review: Radial Engineering Pro Series

It’s unusual for AT to devote significant column inches to the basic utilities of audio production and live sound. Cables, stands and direct boxes only occasionally rate a mention, unless of course they’ve reinvented the wheel in some way. More often than not, however, it’s a problem with one of these items, or in fact the absence of one of these items, that will stop a project or installation dead in its tracks. Like my dear old dad says of nuts and bolts: ‘It matters not how many you have, when a job comes up it’s always the size you need that’s missing.’ So it was when I was asked to manage a live installation for Melbourne band Royalchord. Ten channels of computer driven sequencing, samples, keys and live processing of onstage performances posed some interesting problems. Add to that another five instruments requiring direct inputs and you’ve exhausted the resources of even the most well equipped venue.

Thankfully, Canada’s Radial Engineering had all my bases covered with its Pro Series of DIs and reamp’ers. They’re not new, but they continue to offer a range of solutions for specific tasks, including a high-density multichannel option; a product that many of Radial’s competitors seem to have abandoned. I didn’t make use of the entire product range but was certainly able to give several items a stern road test.

RETREADS

First up is the ProRMP Studio Re-amper – a passive impedance matching unit employing a custom wound transformer to convert a ‘Low-Z’ input signal into a ‘Hi-Z’ instrument level output. Slightly smaller than your average Boss pedal, this 14-gauge steel enclosure is built like a poorly camouflaged aquamarine tank. Radial’s clever bookend sleeve design creates an overlapping buffer around three sides of the case, protecting all switches, connectors and controls. An internally welded I-beam frame promises to maintain rigidity against all manner of stresses, ensuring the internal board and solder joints remain intact no matter how rough the treatment. This commitment to durability is backed up by a three-year transferable warranty, which is as reassuring as it is astounding in our culture of enforced obsolescence.

Input to the unit is via a balanced female XLR (with an impedance of 600Ω) that’s configured for +4dB line level. On the opposite face a standard ¼-inch TS jack delivers an unbalanced instrument level output. A recessed output level pot is also provided to match the recorded signal with that of the original instrument. The level can be easily adjusted using a screwdriver, guitar pick or – depending on your personal grooming habits – a fingernail. Its position ensures your settings will stay put until you need to change them – a welcome comfort in a touring situation. While the transformer already serves the dual purpose of acting as an electrical isolator, the ProRMP also features a ground lift switch to disconnect pin 1 at the XLR input, interrupting any earth loops. A non-slip rubber pad that covers the entire base of the unit also prevents contact with a guitar amp chassis, which may otherwise cause further interference.

Used commonly in the studio to re-amplify existing DI recordings of guitar and bass, in this case two ProRMPs were perfectly suited to the onstage processing of live vocals. Splits of the main vocals were routed through the internal preamps of my audio interface and a combination of effects were then applied both in the box and post re-amp through guitar pedals and amplifiers on stage. The level trims came in handy when feedback reared its ugly head, and being able to use amp reverb and tremolo on vocals really added vibe to the performances.

POWER STEERING

Sharing all the build characteristics of the ProRMP, the Pro48 is most easily identified by its deep navy blue baked enamel finish. An active DI powered via 48V phantom, the external configuration of the Pro48 is almost the reverse of the re-amp. A ¼-inch TS input jack feeds both into the circuit and directly to a ‘Thru’ output jack for amp driving or as a tuner send. A –15dB pad switch is also located on the input panel. Opposite, a male XLR output (with an impedance of 600Ω) is positioned alongside a ground-lift switch. Inside, a digital switching power supply converts the low-current 48V phantom (from a console or external preamp etc) into high-current 9V internal rails. Designed to minimise the negative effects a low-impedance load might have on an instrument, the high input impedance significantly improves the Pro48’s ability to deliver a flat linear frequency response.

Radial suggests that the Pro48 is ideally suited for battery powered active basses and acoustic guitars, which tend to overload some DIs. Its transient handling capabilities in combination with the pad also means it will nicely complement keyboards and drum machines. I experimented with the Pro48 using a bass, equipped with active EMG pickups, a Wurli 200A and my aging Japanese acoustic. Always the cynic, I must say in this case I’m of a mind to believe at least some of Radial’s hype. When comparing recordings made via the Pro48 into a single channel mic pre and those using the direct input of the same high-end channel strip, the Pro48 produced clear and detailed representations with a significantly improved and open top-end. Without being overemphasised, the Pro48 recordings were more revealing and enhanced the sense of space and air, particularly with the bass, mainly due to the very high impedance of the unit.