An unusual design yields significant sonic dividends
Review by Mike Metlay
ART has been around for a good long while, but it’s not a company known for its monitors (that tended to be the province of sister company Yorkville Sound). With the RM5, though, that’s about to change. We found this remarkable new monitor system to be truly attention-getting, in all the right ways.
Not your average box
The RM5 is a stereo monitor system intended for reference monitoring as well as casual hi-fi and home theater listening. It’s designed to fit in relatively small spaces while producing high yet clear listening levels. That’s all well and good; it’s the remit for pretty much any small speaker we review. How the RM5 accomplishes this task, however, is unusual.
The key to the sound of the RM5, particularly on the low end, is its construction. Each speaker is a heavy, rigid aluminum unibody design, 12.4 x 7.6 x 3.6 inches in size. That’s not a typo—these speakers, which are full-size 2-way designs with 5″ woofers, are less than four inches thick. Looking at them straight on, they seem no different than any other small-format monitor, but from the side they look like someone’s shaved off the front of the box and set it up on its own. As a result, they’ll fit in places many speakers won’t, including flush against walls—they come with removable custom stands and VESA mount points for permanent placement on walls.
How does the RM5 get away with having such a small internal volume? The secret is in its dual passive radiators. The aluminum unibody shell of each speaker makes up its front, back, top and bottom; the two sides are flexible passive radiators, rectangular in shape rather than the traditional round design. They’re designed to vibrate in sympathy with the woofer and with one another, to extend the low-end response of the monitor.
Sealed cabinets with passive radiators represent an alternative to cabinets with tuned bass ports. Note that neither design is “better” or “worse” per se; good engineering and careful design can yield world-class results in either case. Most of the speakers we review are ported, but we’re seeing more and more sealed cabinets with passive radiators as time goes on.
The drivers themselves are a 5″ composite woofer and a ring-radiator tweeter with a center plug and waveguide surround for a very wide sweet spot. Amplification is 125W per woofer and 25W per tweeter for a total of 300W, and the crossover frequency is set at 2.2 kHz. Maximum SPL at one meter is 109 dB, and the rated frequency response (±3 dB) is 45 Hz to 22 kHz (the Nyquist frequency for the internal DSP).
The RM5 is shipped as an active/passive stereo system, with all amplification and electronics contained in the Right speaker. A 4-pin locking cable feeds the Left speaker’s drivers, and all other connections and controls are on the Right side. There’s nothing stopping you from reversing the speaker positions if that’s more convenient; you’ll just have to swap the inputs—and remember that you did it!
The RM5 is a completely digital speaker, with internal DSP and 24-bit/44.1 kHz conversion on input. All connections are on the bottom of the speaker, which is held up by a bolt-on metal stand. There’s a pair of XLR/TRS combination jacks for balanced or unbalanced analog signals, a minijack Aux input, and built-in Bluetooth for wireless playback from smartphones or other mobile gear. A 2-prong power cable completes the wiring complement. A small 3-way slide toggle lets you select 1/4 Space, 1/2 Space, or Full Space placement, to compensate for wall or wall/corner mounting. I’d strongly recommend against corner placement, as one of the radiators will be firing straight at the wall.
Controls on the top of the Right speaker include a 3-way roller switch for Theatre/Hi-Fi/Reference mode, a volume roller with center detent for unity gain, and Power and Bluetooth Pair switches. The green power LED turns red when the RM5 goes into low-power Sleep mode, and the Pair button lights up blue when connected.
Putting the RM5 speakers on their stands after unboxing involves attaching hardware to the rear surface, so you’ll need to prepare ahead of time by laying down a soft cloth or towel and placing the speakers on them with their drivers down (they’ll be protected by the front-face waveguides). Also, be careful not to hurt the radiators when picking them up.
Attaching the stands to the rear panels of the speakers requires a set of screws and an included Allen key, but take note that there are extra screws that are slightly longer, that you mustn’t mix up with the rest of the screws. If you attach the stands directly to the speakers using the shorter screws, they will be up-angled at 3º, which works well for desktop setups and shorter stands. If you want them to fire straight forward, you must insert a metal spacer between each stand and speaker, using the longer screws to hold them in place. These speakers won’t work with conventional speaker isolation stands, and I’d be cautious about trying to balance them on Sorbothane domes; they want to sit flat on their stands so their weight is borne stably.
I set up the speakers at Recording’s office studio, using the Full Space and Reference settings. Hi-Fi yields a “smiley face” curve, and Theatre has a huge bass/mid boom that’s great for superhero movies but not something you’ll want to mix with. I worked with them for a few weeks, listening to my reference library tracks and doing editing and mixing with them, driving them with my trusty Schiit Audio Modi 2 D/A and Magni 3 amplifier with a sample rate of 44.1 kHz and either 16 or 24 bits of audio resolution.
ART claims only 3 dB down at 45 Hz with these monitors, which would make them suitable for critical mixing of any music that wasn’t reliant on subwoofer-friendly ultra-low bass. My listening sessions bear this out; there’s a lot of bass to be had, and it’s clear and solid. You can’t quite believe what you’re hearing at first, but the radiators do their job beautifully. You can hear details in low piano notes, 5-string bass, TR-808 kick, and other low-end sources, with good articulation up into the low mids.
The highs are clear and very present; the ring-radiator tweeter throws a lot of high end, and if it’s cranked up it can really sizzle. The mids are interesting, because the RM5 tends to present certain sources like lead guitar and vocals in a very “forward” way, lifting them up out of the mix. It took me some time to figure out how to mix in a way that had the mids gel with the rest of the frequency spectrum, but that effort was a good investment, considering that my mixes didn’t come out shrieky or boomy on even large monitor systems. I found the overall listening experience comfortable at low to medium SPL, and got some guilty pleasure at rattling the walls with the RM5 when they were really cranked up.
These speakers are impressive, especially coming from a company not known for monitors. They have power aplenty, a really solid and detailed listening soundstage, and once you get them on their stands they’re easy to place and set working. All in all, an impressive debut from ART, and a speaker you’re going to want to check out for yourself.
More from: ART, www.artproaudio.com