It's no mystery why in-ear monitoring systems are becoming so prevalent. Being able to hear yourself with pristine accuracy at reasonable volumes is a performer's dream (not to mention what reducing stage volume can do for the front-of-house sound).
Nor is it a surprise that the leading manufacturers of wireless in-ear systems are the same folks already adept at flinging wireless microphone signals across the stage. Audio-Technica has been a leader in wired and wireless microphones (and headphones) for decades, and they've established quite a name for themselves in the wireless in-ear monitoring market as well. We had a chance to test out two Audio-Technica systems, the M2 ($799 list) and M3 ($1,099 list). These Japanese-made systems are identical in specs and basic functions-they differ in their interface and number of available frequencies.
Both the M2 and M3 are frequency-agile UHF units with a half-rackspace transmitter and beltpack receiver. Up to 10 M2 systems can co-exist across 100 selectable channels; these numbers jump to 16 systems and 1,250 channels with the M3. You can use any number of receivers with the same transmitter.
The Transmitters
The Audio-Technica transmitters have left and right inputs on combo 1/4-inch/XLR jacks. Small switches near the inputs offer attenuation of 10 dB and 20 dB if needed. Signal loop-through is accomplished with a pair of XLR outputs. In addition to the input attenuation switches, the M2 has a pair of trim knobs to adjust input level. On the M3, you control these with the menu. Input level metering on the M2 is a simple three-LED affair with peak indicators and mystery level LEDs marked "1" and "2." Input level metering on the M3 appears in the LCD display. The M3 transmitter also has a 1/4-inch headphone output on its front panel, which is a real plus for troubleshooting.
The M3 transmitter and receiver have nice, crisp, backlit LCD displays and a simple one-level menu interface. The M2 system saves buyers money by eliminating these displays, replacing them with knobs on the transmitter and dip switches and potentiometers on the receiver. Most functions accessed with the M3's LCD displays are of the set-and-forget variety anyway, so M2 owners won't be unduly impaired when it comes to actual use.
The Receivers
The M2 and M3 beltpack receivers are quite large and solidly built, with a locking flip-down panel that reveals a battery compartment. The receivers will run a generous eight hours on two AA batteries, which are in an unfortunate death grip and have to be removed with a tool. The top surface of the receivers has a flexible four-inch antenna, headphone output (with locking threads), RF and AF LED indicators and concentric volume and balance knobs. The M2 has a battery level LED that glows red when disaster is imminent; the M3's front-mounted LCD display has a multi-element battery gauge.
The function of the receiver's balance knob depends on the mode the system is in. In stereo mode, the balance control works just as you'd expect-it reduces the volume of one side of the stereo image. In mix (or dual-mono) mode, the left and right signals are summed to both earbuds and the balance control affects their relative mix. This is the more useful mode in most applications, as the performer can be sent a backing mix on one input and their isolated voice or instrument on the other. The balance control then becomes their own "more me" knob, and the sound engineer has one less thing to worry about.
The M2 and M3 receivers have one very nice feature that sets them apart from the competition-an aux input. This aux input can be used for a direct line input (from an instrument or click track or whatever). Even more compelling is attaching a condenser mic for ambient sound pickup. This helps eliminate the "detached" feel of in-ear systems. Plug in Audio-Technica's omnidirectional AM3 mic ($119 list), adjust the mic level to the monitor mix, and you're good to go. There are great psychological benefits to a trickle of ambient sound.
Which brings me to a rhetorical question: Why doesn't every wireless receiver have a simple condenser mic built into the beltpack for ambient pickup? This seems like a no-brainer, with minimal expense and no real technical challenges. The M2 and M3 are a step in the right direction, but their ambient mic requires spending another $100 and managing another cable. They could have mounted a condenser mic in the beltpack, kept the aux input for something else and really shamed the rest of the market.
Plug ‘Em In
It didn't take much listening to recognize that the M2 and M3 are great-sounding wireless systems. Their sound is clean and devoid of compression or noise-reduction artifacts. Some competitive products offer EQ at the transmitter, or treble boost at the receiver. These are corrective measures, and the basic sound of the M2 and M3 need no correction (though your earbuds may).
Both systems exhibit some low-level background noise regardless of volume setting, but this is quickly forgotten when a song is underway. The M2 and M3 are plenty loud-their 65 mW output power is enough to drive most earbuds to unhealthy levels.
Speaking of unhealthy levels, good in-ear systems should have some sort of limiting to protect hearing in the event of feedback or similar audio "event." The M2 and M3 have built-in limiting for this purpose; the M3 offers three level settings and the M2 just one. Unfortunately, the limiting in the M2 and M3 systems doesn't offer a broad enough range of threshold settings to protect some users. If you have extremely efficient earbuds or headphones, or choose to monitor at lower levels, the limiting action will never engage. Audio-Technica is not alone in their approach to limiting, and they and the wireless industry as a whole need to address this serious design shortcoming. Until they do, Audio-Technica plans to include additional information in the M2 and M3 manuals to explain the risks.
It's downright benevolent of Audio-Technica to throw in a set of $120 earbuds with the M2 and M3 systems. Too bad the included EP3s don't sound very good. They have too much muddy bass, and their predominant presence make them sound somewhat brittle and harsh. This makes the EP3s more fatiguing than my favorite affordable earbuds, Shure's SCL3s ($150 street). If you enjoy a "bump and sizzle" sound, the EP3s may make you happy. I found them lacking accuracy, primarily because they de-emphasize crucial midrange frequencies.
Range of the M2 and M3 systems is excellent, with line-of-sight signals staying strong at distances well beyond any you'd need in normal applications. If you stray too far, a variable squelch control will limit bursts of noise until you can scamper back into range.
Overall, the Audio-Technica M2 and M3 wireless systems offer great sound and performance (though the lack of limiting in certain situations is a concern). They offer good value, even taking the included EP3 earbuds out of the equation. If price is a concern, the M2 sacrifices just a bit of convenience to shave off $300. That said, the M3's menu system may be worth the money if you frequently adjust your system's settings. The M2 and M3's aux input is a wonderful feature, and a strong plus.
If you're in the market for a solid, great-sounding wireless system from a trusted name, the Audio-Technica M2 and M3 systems are well worth a closer look.
