The Testbench

Review: Munitio [M] BLK nine millimeter earphones

Ah, now for something *completely* different.

The PR representative from an audio company named Munitio has been offering to send a review sample of one of their products for some time, and I’ve finally taken them up on it. Munitio, based in San Diego, has a somewhat novel line of in-ear monitor (IEM) earphones that it calls “nine millimeter.” Why? Well, the earpieces resemble nothing so much as 9-mm shell casings. I’ve read somewhere that there’s an old tradition among gun enthusiasts of inserting spent shells into their ears as a sort of ad-hoc sound muffler while they continue firing off rounds.

I suspect, however, that the real reason for the bullet styling is that Munitio is “aiming” (ha ha) for a particular demographic, basically young people with a taste for hip-hop. That suspicion is greatly reinforced by the fact that the headphones’ sonic signature is skewed toward the low-frequency end of the spectrum.

The earphones come in a round case, well packaged with four sets of what Munitio calls “SiliconeHollowPoints” as well as a cleaning cloth and fabric case. The “SiliconeHollowPoints” are the silicone tips that one actually inserts into the ear canal. It comes with two sets of medium-size tips and one each of large and small. I’ve found that I get the best seal and most comfortable fit with the small tips. I started with the mediums that come installed on the earphones and, to tell the truth, they actually hurt a little. The documentation makes it clear that unless you find the tips that fit your ears best, you won’t get the ambient-sound isolation that the earphones are capable of, not to mention a loss in the deep bass response that Munitio’s products have gained a reputation for.

The set’s construction is quite solid. The body of the earphones I was sent is finished in matte black and is machined from copper alloy and coated in titanium. These housings hold (what else?) 9-mm drivers with rare-earth neodymium magnets. Frequency response is rated at 12 Hz to 22 kHz with sensitivity of 100 dB (±3 dB) at 1 kHz. These are somewhat heavy earphones.

The cord is an interesting affair. Rather than the typical vinyl-jacketed wire, it’s a Kevlar-reinforced fabric cable. It’s supposed to resist stretching so as not to damage or short the copper wiring. I’ve found that the cord does introduce some microphonics; I hear it when the cord brushes against my clothes. At the business end of the cord is a straight 24k-gold-plated, 3.5-mm plug. Meanwhile, at the entrance of the cords to the earphone housings, there’s a conspicuous lack of strain relief, which might cause durability concerns. But in my experience, it’s not an issue; they’re pretty rugged. Accidentally yanking them out of my ears rather forcefully the other day hurt me a lot more than it seems to have hurt them.

This [M] BLK set is called “tactical” in part, I suppose, because of the matte black look, and in part because there’s provision for hands-free operation of an iPhone or Droid. Having access to neither of those devices, I must leave that feature unexamined. I have, however, read comments online to the effect that it works well.

The source I’ve used with the Munitios is my venerable 6th-generation iPod Classic (160 GB). I have also tried amping them with my JDS Labs BassBoost cMoy headphone amplifier, but the jury is still out on that. My iPod is packed largely with MP3-encoded music ripped with Exact Audio Copy and the latest version of the LAME encoder set for V0 VBR. My usual IEMs are Etymotic Research ER-6is, which the audiophiles out there will know as a somewhat “analytical” set of IEMs that is kind of light on bass.

OK, so on to the sound. I like to baptize earphones with music that I know extremely well, so I started with The Beatles and “Abbey Road.” I wanted to find out right away how good/bad the bass response from the Munitios is; might as well start with Paul’s fat bass line on “Come Together.” What I heard was bass, and lots of it. Unfortunately, that bass wasn’t as tight and crisp as I might have liked. It was a little on the mushy side, frankly. Meanwhile, mids and highs were certainly present and fairly clean.

Moving on to some jazz, I fired up John Coltrane’s “Living Space,” knowing that there are some tunes in which ‘Trane explores the bottom register of his tenor sax’s range to great effect. There again, the sax thundered into my ears, but with a little hint of mushiness. Meanwhile, Elvin Jones’ cymbals had nice sizzle, so the treble end was covered well.

I explored various genres and periods of music in this way, and in the process, I rediscovered the EQ built into the iPod. Generally, I don’t use it at all as it really sucks down battery power. But Munitio’s documentation encourages use of equalization with the earphones. I must say that it made a huge difference. I found myself gravitating toward the Dance and Piano presets for a lot of things. With others, the genre-specific setting worked for the type of music it’s supposed to go with, i.e., for most jazz, the Jazz preset sounds good.

With about 10 or 12 hours on the drivers, things started to change a bit for the better. I tried Krzysztof Penderecki’s “Utrenja,” performed by the Warsaw Philharmonic Choir and Orchestra in a release on Naxos from a year or two ago. The deep rumblings of the choir’s basses seemed to have tightened up, while the high end retained its crystal clarity. Hey, I’m starting to like these things!

I’ve never been so sure that I believe in “burn-in.” I’ve always thought that it was your brain that got “burned in” as it adjusted itself to the sonic signature of a headphone driver or speaker system. But with time on the drivers, the sound signature of the Munitios does seem to shift somewhat. It’s gotten more balanced, with less of a veil over the midrange and a nice overall punchy feel.

Ultimately, these little bullets have to head back to San Diego, but I think I’ll miss them. Overall, I prefer the more natural bass I get from my ER-6is. But the Munitio earphones are quite comfortable with the right tips, and after some burn-in, are presenting a relatively balanced sound albeit with a bit of “bass in your face.” If you’re a “basshead,” you can do worse. And, if the idea of walking around with bullets in your ears appeals to you, these are definitely your IEMs.

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