RealTraps MondoTrap room acoustics treatment:
Page 2 But we get along well, and I like our new digs. I love the view, the good restaurants, the excellent bakery just down the street. But the stereo now occupies the apartment's main living space, which is adjacent to the single bedroom (our son sleeps there). This puts some restrictions on the stereo's use. I can't listen seriously while dinner is being prepared—too many clanking pots. I can't listen above minimal volumes late at night. And I can't fill the room—at least, not permanently—with eight objects that, in shape and scale, resemble those obelisk thingies floating around in 2001: A Space Odyssey.

I exaggerate. RealTraps MondoTraps aren't that big. In such a small apartment, however, they're . . . big. But this is Stereophile, not Metropolitan Home. What matters in these pages is not how beautiful a MondoTrap is, but how beautiful it makes the music sound.

Size matters
The RealTraps MondoTrap isn't ugly—it's quite unobjectionable, really. It's just big because it has to be. The thing doesn't work on your psyche, aura, or some mystical energy field, as some room-treatment products are claimed to do. They work on the low-frequency part of the soundfield, and if you want to absorb low frequencies, size matters. I begin to understand why magic rocks have a following. They're small.

The MondoTrap is a chunk of "double-density" rigid fiberglass covered in a sound-transparent fabric. RealTraps also incorporates a "limp-mass membrane" that they claim doubles the low-frequency absorption. A powder-coated steel frame makes the Mondo durable and easier to handle. Each MondoTrap is 57" tall by 24" wide and 41/4" thick. Its 28-lb weight is light enough to handle easily, but heavy enough to require fairly serious hardware to attach it to a plaster wall. Each MondoTrap costs $299.99. The Corner MondoTrap, designed to snuggle unobtrusively into a corner of a room, costs $50 more.

All told, I was sent eight MondoTraps—$2400 worth of sound treatments. Considering what they did, the price was a bargain—many cables and power-treatment products cost more and accomplish far less—but $2400 is real money.

Empirical evidence 1
Earlier, I mentioned that science has two complementary foundations: theory and rigorous, quantitative observation. So far, I've mentioned only the theory part. If you want scientific proof that the MondoTrap does what RealTraps says it does, by all means trust your ears—but first, look at fig.1.

Fig.1 In-room response, 80–200Hz, of right-hand loudspeaker with (blue) and without (red) three MondoTraps stacked behind speaker. (10dB/vertical div.)

The first thing I did after receiving the eight MondoTraps and removing them from their eight large boxes was to stack three of them in a corner of the room. (The other five were in a different room, door closed, so they had no effect). Fig.1 shows the Before (red) and After (blue) frequency responses, measured at my listening position (footnote 4). Keep in mind that only three Mondos were deployed for this measurement. The big dip in the response at about 100Hz in the Before spectrum means that in that frequency region, the sound level at my listening chair was down by about 15dB. With three MondoTraps stacked in the corner, the dip went away. The effect was repeatable, easily measurable, and dramatic.

Absorb more bass and you're left with more bass, at the frequencies where you need it most. It sounds weird, but it makes sense. The MondoTraps did what Ethan Winer claimed they would: They measurably evened out the bass response.

Empirical evidence 2
There's another kind of evidence that, if not exactly rigorous and scientific, is what most audiophiles rely on: the evidence provided by their ears. I lived with the MondoTraps, in various non-ideal configurations, for about 10 months, through two pairs of speakers, several integrated amplifiers, five phono cartridges, and three digital front-ends.

I knew right off that the MondoTraps wouldn't be staying—they're just too big for my small space—so I didn't deface my plaster walls with lag bolts or other mounting hardware. Consequently, my installation was less than ideal. I distributed the Traps throughout the room in various ways, keeping most of them near the floor but using various pieces of furniture—tables, chairs, dog crates, benches—to position some of them up near the ceiling. I used the spacers RealTraps provides to separate the Mondos from the wall by the prescribed couple of inches, which Winer says helps them trap more sound.

With the MondoTraps in place, bass instruments sounded fuller, clearer, more palpable. Kick drums had a more visceral, focused thump. The subjective effect of trapping bass frequencies is to put more bass into the room—not dull, distorted, low-rider bass, but the kind that makes you sit up and smile. That's what Ethan Winer had told me to expect, but there was another important effect that I can't quite explain.

In my years of listening to music, I've become accustomed to having to strain to hear into the music, to hear the inner voices that make music come to life, texturally and spatially. For me, being able to hear those inner voices is the difference between being enveloped in music and merely observing it analytically, as if at a distance. Often, however, it seems as if something—a glaze—is superimposed on the music that I have to listen through. The word glaze suggests a highish-frequency effect, and that's the way I've always heard it. Winer tells me that, in addition to absorbing the lows, the MondoTraps are designed to not absorb much energy at the mid- and high frequencies; he doesn't want his Traps to deaden a room. Still, the MondoTraps seemed to reduce the glaze in my room, making it easier for me to hear into the music and enjoy it more. Far from deadening the room, the MondoTraps made the music more involving. Go figure.

My predicament
I won't miss the mondo characteristics of the RealTraps MondoTraps: large objects piled in corners, leaning against walls, obscuring art, and occupying vast expanses of scarce living-room space. Of course, had I mounted them properly, they'd have looked neater and been less intrusive, but then I'd have big lag-bolt holes in my plaster walls—so I can't say I'm sorry I didn't drill.

What I will miss—and this is the conclusion I want you to take away from this review—is the mondo effect they had on the sound. The MondoTraps worked very well. Suffice it to say that my experience with them has caused me to reconsider my housing decision. Is a view of the ocean and a 10-minute walk to the best bread in New England worth giving up the best possible sound?

I refuse to choose. I will continue to seek a solution that integrates better into the design of my small room. But that's a personal aesthetic decision that has nothing to do with the MondoTrap's performance. In pure audio terms, the MondoTrap wins my highest praise. It does what RealTraps claims it does, does it well, and takes up no more space than it must to do the job. This ain't no "lifestyle" component.

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Footnote 4: These measurements were made using FuzzMeasure from Smug Software, an audio tool for the Mac that John Atkinson discussed in the January issue and which is currently listed in Class K of Stereophile's "Recommended Components.