EQ Magazine, December 1998, pages 18-20

EQ Live: Radian Audio Engineering RPX-112P Loudspeaker by Steve La Cerra Although you may not be familiar with the name Radian Audio Engineering, there’s a good chance you’ve already heard their technology. Radian has been manufacturing component drivers and diaphragms for about 10 years. Until recently their drivers have mainly been used in OEM applications, but now Radian has started marketing complete loudspeaker systems that incorporate the driver technology they’ve developed. One of those systems is the RPX-112P, a full-range, two-way loudspeaker designed primarily for use as a stage monitor. While its shape and size suggest that it is intended for horizontal use as a floor wedge, it can also be used vertically for small house systems, or as a fill speaker in large PAs. Unlike most of the wedges we encounter, the RPX-112P uses a single, 12-inch coaxial driver in a ported cabinet. Radian sent EQ a pair of RPX-112P’s, which we dragged around the country for three months, using them mainly as vocal monitors in venues that ranged from several-hundred-seat clubs to outdoor festivals of more than 5000. The RPX-112P cabinet is a serious piece of construction — exterior-grade, 13-ply, Baltic birch with a very strong, perforated-steel grille protecting the driver. This kind of construction does make the cabinet heavy (59 pounds), but a recessed carrying handle makes it possible for a single person to lift. As are all of the loudspeakers in the RP Series, the RPX-112P is finished with a proprietary cabinet covering called Duradian™, which appears to be a rubberized coating applied to the birch. In any case, it looks good, resists scratching, and can even be provided in custom colors. Our first show with the RPX-112P’s was outdoors on a stage of approximately 40 x 25 feet. Our PA company had already placed three monitor mixes downstage. We decided to leave the stage-right and center mixes as is — each with two 1x15-and-a-horn wedges. We placed a single RPX-112P at the stage-left position, and when we grabbed a Speakon® cable to wire the cabinet, we noticed a minor annoyance. The input panel of our RPX-112P was mislabeled "pin 1 = LF, pin 2 = HF." In fact, we were using the full-range, passive version where the pin 1 pair of the Speakon accepts full-range audio (the biampable RPX-112B accepts audio as labeled). After we knocked our heads a bit, we realized that the worst thing that could happen was that we’d send full-range audio to the woofer, so we connected the amp, powered it up, and everything was fine. Radian Audio Engineering has now corrected the label problem, which appeared on a few early RPX-112P’s. If you own a ‘112P with a mislabeled input panel, Radian has a correction label for you. We started our monitor check with the other mixes, which — on two 1x15-plus-horn cabinets per mix — were able to produce some pretty loud sound. It

appeared initially as if the one Radian box really wouldn’t be enough against these giants, but the one Radian cabinet held its own quite nicely. The RPX-112P produced very clear audio in the vocal range without making us feel like there was a horn sticking a dagger in our ears. In other words, it sounded smooth in the top end and didn’t the produce peaky, high-mid crap like most other monitors. The bottom end of the vocal range sounded tight and controlled, possibly due in part to the dampening of cabinet resonance from the Duradian finish. We continued using the RPX-112P’s, sometimes as a pair, sometimes with one cab on a mix. For the most part, results were consistent regardless of room/equipment variations: clear vocals that cut through on-stage din without poking you in the eardrum. There was one aspect of this Radian cabinet that we were a bit mystified with: the angle of the front baffle. We felt that it was a bit on the steep side. If a tall person (say, six feet) stands directly in front of this cabinet, the baffle blows toward their waist. Shorter people, or people who stand back farther from their monitors, will find this less of a problem. It didn’t really sound off-axis, probably because the conical coax dispersion pattern results in wider vertical coverage compared to traditional rectangular horns (which tend to have more narrow vertical dispersion). In general, the coax design kept spill contained because the horizontal dispersion is considerably tighter than a 60 x 90 horn. We placed a 2x4 under the cabinet to modify the angle. Radian has informed EQ that they are changing the angle, and may build a cabinet that can be rolled to rest at a different angle on each side. As part of our "experiments" on the RPX-112P, we used them as keyboard monitors. It’s interesting to note that a seated keyboard player (or drummer) is directly on-axis to the front baffle. We ran a foldback mix, which included an Alesis NanoPiano, Korg M1, and Yamaha DX7-II, into the RP-112P’s. Although the cabinet didn’t produce earth-shattering low end (nor was it designed to), the mix was tonally full and balanced. Radian’s engineers have done their homework on the crossover to filter out low frequencies that the 12-inch driver might otherwise struggle to reproduce. The result is that the RPX-112P doesn’t sound like it’s trying to do something it really can’t. Radian Audio Engineering has come up with a serious monitor in the RPX-112P. It might be on the pricey side for the MI market, but professional users who prefer to buy once and buy right will find the money well spent. (The RPX-112P does come in more affordably than some of its competition.) It sounds very good and the cabinet will hold up to road use. If you’re looking for professional-quality, compact vocal stage monitors, the RPX-112P is a strong recommendation.

Road Test MANUFACTURER: Radian Audio Engineering, Inc., 600 North Batavia Street, Orange, CA 92868. Tel: 714-288-8900. E-mail: Info@Radianaudio.com. APPLICATION:Full-range speaker for professional live sound reinforcement.SUMMARY:Single 12-inch coax driver with 2-inch-exit high-frequency compression driver in a ported cabinet. Speakon® input and parallel connectors.STRENGTHS:Well-built cabinet; very clear reproduction in the vocal range; looks good.WEAKNESSES: Angle of front baffle is somewhat steep; cabinet is heavy. PRICE: $1695.