At one time or another, everyone in audio has seen a list of the great lies of rock 'n' roll. You know, the ones containing, “This is one of Jimi's old Strats,” or, “Your name will be on the guest list” or any of 50 other falsehoods. These days, the list should be expanded with, “Don't worry, in-ear monitors will protect your hearing.” Actually, that statement is partly true and partly false — it all depends on the application and the skill of the user. As with shotguns or banana creme pies, earpiece monitoring can be dangerous in the wrong hands or when used improperly.
Regarding in-ear monitors (IEMs), there's no end to the amount of “heard it from a friend” or “read it on the Web” misinformation. Seeking some facts about hearing health and in-ear monitors, we enlisted the help of Michael Santucci, a credentialed audiologist and founder of Sensaphonics Hearing Conservation; Paul Owen, VP of Michigan-based regional sound company Thunder Audio (and Metallica's longtime monitor engineer); and Mike Dias of IEM manufacturer Ultimate Ears.
Audiologist Michael Santucci uses an otoscope to examine a patient’s inner ear.
“People assume that in-ear monitors are safety devices, and I contend they are not,” Santucci says. “They are earphones, and some are so loud they can reach a 140dB output. That's louder than wedges, so where's the safety? In-ear monitors are not safe unless somebody directs you on how to use them.”
The typical manufacturer response is a disclaimer in the user manual that states something about the hearing safety benefits of IEMs when used properly. Yet, according to Santucci, “They can't tell you how to do that or find a way to measure it. There's no ability to tell people how loud these things are in an everyday setting. We've developed technology to take sound level measurements at the eardrum, but an audiologist has to be at the soundcheck; otherwise, there's no way of determining how loud your IEMs are in an everyday setting.”
With artists having control over the beltpack's playback volume, the issue of providing safe hearing is complex for the monitor engineer. “I find when you start on a tour, you begin with the packs considerably lower, and the further you get into it — because the threshold of hearing has moved — the artists are running hotter and hotter toward the end,” explains Owen. “One good piece of advice is to start the tour with the in-ears turned down as low as possible. If you start having artists walk offstage with ringing in their ears, you're monitoring too loud.”
Santucci agrees, but adds, “The presence of ringing in the ears after use means you're listening too loud or too long or both. However, don't assume that the absence of ringing means you're safe. Seventy percent of industrial workers who have a reported hearing loss have never complained of tinnitus.”
“You've got to work with the artist to settle into a safe zone,” says Owen. “But a lot of this comes down to the artist: We can't entirely monitor what's going on inside their ear canals. However, there are things we can do to protect the artist. One mistake people make is not to set the squelch properly. I've seen a lot of people using beltpacks with the squelch set wrong, so when anyone goes offline or loses power, you'll see all the artists onstage pulling their earpieces out.”
Santucci feels a key factor in a good in-ear monitor is the earpiece's ability to seal external sounds. “That's why we only offer custom-fit products. You have to create a really good signal-to-noise ratio in that space within your ear to be able to hear,” he says. “In this case, the ‘noise’ is the stage volume. If you can't effectively block that out, you'll have to turn the signal louder — it's simple physics. If the stage volume is 110 dB and you have leakage in your earpieces, you're not going to hear that signal at 100 or 105 — it will be more like 116 dB.”
The downside of a good seal is isolation from hearing the audience or being able to talk to other bandmembers between songs. Sometimes, this can be countered by adding feeds from some audience mics into the personal monitor mix, but this has also its dangers. “You can put in ambient tubes to let in some outside sounds or you can bring in some ambient mics, but either of those will increase the volume inside the canal because you're not 100-percent blocked off from the outside,” notes Owen. “And if it's a constant ambience — rather than ambience mics brought in at the end of each song by the engineer — you've got to run higher to get over the ambience and can start getting into some serious levels. I use [Aphex] Dominator IIs across all my in-ears to protect against anything I feel is out of control. That also catches any spikes that come in so the artist doesn't get the full blast of it.”
“For the artist who feels in-ears over-isolate them from the audience,” adds Dias, “or want a more natural ambient sound, there are tools in the in-ear arsenal to compensate for that, such as a mix of ambient mics or monitoring systems with passive or active ambient features.”
One danger from too much isolation comes when musicians decide to “fix” the problem by wearing an earpiece in only one ear. “When players take one out, their brain loses its ability to do binaural summation, where two ears together add up to a 6dB increase in your perception of loudness,” Santucci explains. “If you're hearing 90 dB in both ears, your brain thinks it's hearing 96 dB. If you take one ear away, then that one ear has to go from 90 to 96 to sound like 96. And now the other ear is open and getting bashed by the band, the P.A. and the crowd. So this loud sound coming into the open ear causes you to turn the other ear up even more. In terms of ear safety, using one earpiece is a dangerous practice — it could actually be worse than using none at all.”
“There's a common misconception that an artist can use just one earpiece and still use stage monitors, but this results in the worst of both worlds,” says Dias, who offers a simple experiment to demonstrate this. “Have someone stand onstage with a beltpack using one ear and turn it up to a comfortable performing level. Now shut the beltpack off and run the stage monitor to a comfortable level. When you turn the monitors and the single earpiece on, the artist inevitably thinks the in-ear sounds weak and cranks it up to compensate. But when you turn the wedges off, the artist will notice that the earpiece is too loud. In the case of one-ear listening, you don't get the benefit of hearing protection and you don't get the accuracy benefit of the in-ears.”
There are numerous other illusions that are regarded as truth, such as whether ringing in the ears means those hair cells are gone forever. “The answer to that is ‘no,’” says Santucci. But can your hearing heal? The answer takes the form of a “good news/bad news” scenario. “It's absolutely true that hearing can heal, because there are both temporary effects and permanent effects. The temporary effect can continue on for a long time unless you get away from those loud sounds,” Santucci warns. “I have a study of a musician's hearing profile over eight years of using our in-ear monitors. It shows his bad ear — which was exposed to the band — didn't change for the better or worse, but his other ear had a small notch that actually went away. How did that happen? Well, it could be he never gave his ears enough time off the road to recover before testing. The point is, there's a possibility that things can improve, but hearing loss from loud sound is permanent.”
George Petersen is Mix's executive editor.