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Published July 15, 2003


RBH MM-4 Loudspeakers and MS-8.1 Subwoofer

The RBH MM-4 satellite is the speaker most likely to survive a two-story fall. Though only 7" high, its diecast-aluminum enclosure and metal grille make it the toughest speaker on the block. It would make a great cannonball. The MM-4 is best known, however, as part of RBH’s esteemed Compact Theater, available in 5.1- and 7.1-channel packages. For those living with two channels, a pair of MM-4 satellites ($249/pr) can be arranged in a 2.1 package with the Compact Theater’s MS-8.1 subwoofer ($399 each). I did just that.


Just try testing the MM-4’s toughness with a quick rap upside its head. Hurts, doesn’t it? I’m not sure about the musical tastes at Roger B. Hassing’s (RBH) corporate offices in Layton, Utah, but they do seem to like heavy metal in their speakers. Where’s all the plastic, the fiberboard? Even the speaker terminals are metal -- the big-lug, gold-plated kind. It’s no fetish; it’s science. The inertness of the metal construction reportedly makes the speakers resistant to resonance and distortion.

According to RBH, the 4" aluminum driver also minimizes distortion at low frequencies better than typical paper or plastic drivers. Paired with a 1" silk-dome tweeter in a compact enclosure (7" tall, tapered toward the peak, 5" wide, and 4" deep), it helps the tiny MM-4 play louder and with greater dynamics than many other compact systems. But with only 4" drivers, the MM-4 can reach down to only about 100Hz, and so is not easy to match with a subwoofer. At such a high crossover, the sub must combine power with fluidity. Even then, it risks diverting the listener’s attention when it becomes too obvious where those double-bass notes are coming from.

Though not encased in metal, the MS-8.1 subwoofer is built for the job. It uses two 8" aluminum-cone drivers -- one front-firing, the other down-firing -- with a 200W amplifier in a side-ported, medium-density-fiberboard cabinet measuring 13" high, 11" wide, and almost 14" deep. Nothing about it looks compromised: It has five-way binding posts (not cheap spring clips) for its speaker-level connections, a variable crossover from 40Hz to 160Hz for line-level connections, variable phase control, a 230V/115V switch, detachable power cord, dual inputs and outputs, and a heatsink on the rear panel. And, at 35 pounds, it’s a hefty little package. It impressed me even before it played a note.


The MM-4 and MS-8.1 were plucked from a 5.1-channel edition of RBH’s Compact Theater, where they were supplemented with a Marantz SR7000 audio/video receiver, the excellent Sony DVP-NS755V DVD/SACD player, and cables by Straight Wire and Analysis Plus.

When it came time for two-channel evaluation, I moved the RBHs into a system with the Antique Sound Labs AQ1003DT, a 30W vacuum-tube integrated amplifier; a Rega Planet CD player with modified ART Di/O D/A converter; and the following cables: Canare Star Quad with Neutrik RCA connectors, MIT Terminator 3, DH Labs D-75 digital cable, and Analysis Plus Oval 9 speaker wire. The two MM-4s were connected to the MS-8.1 via line-level outputs. I compared them with the Axiom M2i speakers and EP125 subwoofer.


If it were a living being, the MM-4 would be a freak of nature. This tough nugget has an amazingly clean top end, plays louder without obvious distortion than anything I’ve heard for its size, and projects a warmish, embracing midrange -- not your typical "home theater" speaker.

With nicely recorded female vocals, such as those of the now ubiquitous Norah Jones on Come Away with Me [Blue Note 32088] (producer Craig Street is a star-maker), the MM-4 sounded like real music -- not the coughing, hacking, tinny concoctions of a teeny-weeny speaker tailored for movie soundtracks. That is to say, it didn’t sound overly bright, like a lot of what you hear in its price range.

The MM-4 was equally resilient with the more demanding, more lo-fi growls of Shane MacGowan on "Aisling," from MacGowan and the Popes’ The Snake [Warner Brothers 85421]. The MM-4 delivers this song with a midrange authority and clarity I didn’t expect from something so small.

Relinquishing bass is the logical compromise with a small speaker, but the MM-4 gives up more than that -- it’s rated down to only 100Hz, making it a challenge to find a subwoofer that does its job without extracting too much information from the MM-4’s lower-frequency region. The ear should not be able to pick up the source of low frequencies in a subwoofer-satellite system. If, for example, the crossover frequency is set too high, the sound becomes localized; instead of a nondirectional signal, you might hear voices or instruments coming from the sub’s direction. That’s ruinous. If the crossover is set too low, the MM-4 will give out before the MS-8.1 steps in, leaving part of the frequency range unaccounted for.

A crossover setting of about 115-120Hz worked best with the MM-4 and MS-8.1 in my room, but your space might require a different setting. This crossover frequency produced a good blend, without the sub becoming directional. Bass sounds on The Snake were authoritative and quick. Not many subs in the MS-8.1’s price class could pull off this feat with the MM-4. These speakers were literally made for each other, and they sounded it.

I recommend that owners experiment with the crossover frequency and volume control, then with the variable phase control. If you’ve never owned a sub and don’t know crossover from phase, RBH’s manual won’t help much. It’s not that instructive with respect to setting up the system. The first-timer won’t even know how to connect it to the rest of the system, whether by speaker wire or by line-level interconnects. A good dealer will help in this regard, and is highly recommended.


The MM-4 rules the squirt-speaker division, but concedes too much in both size and performance to rule its price class. The $255/pr Axiom M2i has a more authentic midrange, a far bigger soundstage, and sounds more well-rounded, even if it plays no lower than a modest 60Hz. However, the MS-8.1 stands up to any sub in its price class. In both substance (35 pounds, dual 8" aluminum drivers) and style (substantive bass energy without one-note slurring), it overpowered Axiom’s lightweight EP125 ($380 each).


The RBH Compact Theater remains my first choice for a budget-priced home-theater setup. There, the MM-4 benefits from a center-channel and, with the correct processing, the option of playing a CD (or SACD or DVD-Audio) in a multichannel format.

In a two-channel system that demands the smallest satellites, the MM-4 makes a perfect companion in an apartment, small den, or even as a multimedia speaker. It is a well-made, smartly designed speaker that, with the proper sub, can rock around the clock.

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