In-ear monitoring has been one of the most profound developments in live sound and performance in recent decades. In-ear monitors protect ears from dangerous sound pressure levels, has the potential to give incredible clarity, and greatly reduce stage volumes for better house mixes. Their main drawback is their tendency to deliver a sterile, detached sound. Ambient mics added into the mix can help, but many performers still find their sound uninspiring.
From my earliest days with in-ear monitors, I've often wondered why ambient mics couldn't be placed on the earphones and blended back in with the monitor mix. Such a system would allow you to hear the sound around you as if you didn't have your ears plugged, while enjoying the clarity and hearing protection of in-ear monitors.
Turns out I wasn't alone in considering this—around the same time (2006) Sensaphonics patented a binaural ambient mic and in-ear monitor system. The system has been refined and improved over the years, but until now required expensive custom-molded in-ear monitors. The latest Sensaphonics 3D-U AARO system (List Price: $1,500) brings the magic of ambient mic “injection” to universal-fit earphones at a lower price point.
In-ear revolution
I used the word “magic” above deliberately, because the effect the binaural mics have on the in-ear monitoring experience is nothing short of amazing. I generally don't write glowing reviews, but the 3D-U AARO made me a believer within the first five minutes. Before I expand on the experience, though, let's explore the technology.
The 3D-U AARO system mounts an omnidirectional condenser microphone on each earphone. The signal from each returns to the beltpack to be blended with the monitor signal. Positioning a mic on each ear preserves a natural stereo field, complete with amplitude and time (delay) cues. The brain is convinced, accepting the ambient mic sound as if it were hitting the eardrums directly. The response of the mics is uncolored, and their default volume is an exact match for your unadorned ears.
The proprietary earphones attach securely to the beltpack with a multi-conductor cable that's tough yet flexible, and can be replaced in the event of damage. A standard 1/8-inch stereo cable connects your wireless monitor receiver to the AARO beltpack, which has handy strain-relief hooks for both input and monitor cables.
The AARO beltpack is built like a brick, with stiff switches and crisp controls. A flip-open panel reveals three switches and one knob. The first switch engages a generous 10 dB bump in bass response. The second switch adjusts the overall volume level to compensate for single- or dual-driver earphones. The final switch engages a brick-wall limiter to protect your ears from extreme peaks or runaway feedback. The sole control knob reduces the ambient volume to the earphones in 4 dB steps to a maximum attenuation of 20 dB. This is useful if you're on a very loud stage and wish to have less ambient sound competing with your monitor mix.
In addition to a partially recessed power switch, the top of the beltpack has a switch which puts the ambience signal at full volume. This is the switch you'll flip if you have the ambience reduced in volume for performing but wish to carry on a conversation between songs. The top of the beltpack also has low battery, peak limit and “loud” LEDs for both monitor and ambient signals. Except for battery polarity, the various functions and controls of the AARO beltpack are clearly labeled.
Plug them in
With signal from the mics flowing back to the earphones, you now have the best of both worlds: the precision of in-ear monitors with the natural ambience of the stage. Drums sound like drums, your acoustic piano is clearly audible, and the acoustic guitar in your hands actually sounds like it should.
I used the Sensaphonics system while playing viola, and the sound of the instrument under my left ear was just as I expected it to be. Later, in a quieter acoustic music setting, I played acoustic guitar with the system and enjoyed hearing the natural sound of the instrument. I turned the ambient mics down a few times mid-song for comparison, and it was as if someone had pulled thick curtains over the sound. You get spoiled quickly.
Sensaphonics went to great lengths to make the ambient sound match your natural hearing in both overall volume and frequency response, and they succeeded terrifically. I quickly forgot I wasn't hearing “natural” ambient sound, and was even able to carry on normal conversations without speaking too loudly or too quietly.
I played the same music through the Sensaphonics earphones and my studio monitors. Comparing the direct (earphone) sound to the ambient mic pickup was an eye-opener. Though the top end was a bit smeared and stereo imaging less distinct, the sound of the ambient mics was amazingly close to that of the direct monitor audio. The Sensaphonics system passed this torture test admirably.
The single-driver earphones that come standard with the 3D-U AARO system sound excellent, and a dual-driver option is available for $300 more. The single-driver model had plenty of bass for me, with nice clear highs and good midrange definition. If you like more bottom end, the bass boost switch piles on the big, pillowy low bass.
The AARO limiter is quite transparent, but it has a very high threshold. It may shave a few dB off a peak (i.e. from feedback), but it won't protect you from excessive long-term SPL. The Sensaphonics system gets uncomfortably loud even with the limiter engaged, and testing this feature wasn't much fun. I'd love to see a variable limiter threshold for those folks with sensitive ears.
Perhaps in a case of design-by-lawyer, the AARO system has no means to increase the ambient level above what your ears would normally perceive. Would such a boost increase the user's chance of hearing damage on an extremely loud stage? Maybe. Might it be a huge help for those playing on quieter stages, perhaps in an acoustic or “unplugged” setting? Absolutely. In several cases, I found myself wishing for just one more detent on the knob to increase the ambient level so I could better hear an acoustic instrument or my own voice. More than once I found myself cupping a hand to my ear when singing.
For universal-fit earphones, these fit extremely well. Even after several hours, I experienced no pain or discomfort wearing the Sensaphonics earphones. I wish the earphones were a bit smaller and lighter, however, and I think the glossy black color doesn't even try to blend in. A middle beige-brown would be preferable, or perhaps two or three different colors.
Game-changer
As a long-time audio tech, it's rare I use or test a product that really surprises me. The Sensaphonics 3D-U AARO system did just that. The way it blends in ambient sound and essentially lets you “turn down your world” in a transparent fashion is truly impressive. Now I'm hoping Sensaphonics will find a way to lower the price point so more users, especially those in churches can enjoy this terrific technology.
