Samick Motherlode

December 2014
more... How-TosSeptember 2007

The Sound of Silence

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Can You Hear Me Now?
Thus, knowing how our ears are affected by sound, it may come as no surprise that the Sensaphonics report details the frequencies where musicians suffered the most hearing loss: 1500Hz, 2000Hz, 3000Hz, and 6000Hz. Of course, those numbers alone may mean little; Dr. Connie Lenz, an audiologist in Cedar Rapids, Iowa, broke down the importance of these frequencies for us. “Those are the most important frequencies in speech, with the most important being 2000Hz [see the Audiogram sidebar]. There’s a lot of information there.”

Peter Stroud, a guitarist who has been playing live shows for 30 years and tours with Sheryl Crow, offered up the following, “Whenever you do a hearing test, you’ll find a drop, and it’s in the 1000Hz-3000Hz range. That’s usually due to cymbals, and it’s just a very sharp peak. It’s a noticeable area for a lot of musicians.” So the general consensus from all sides is the same; frequencies needed for speech are the same that are damaged from exposure to loud music.

The report on hearing loss in musicians also states that 60% of those studied reported occasional tinnitus. Dr. Lenz explains the condition: “Tinnitus is a high-pitch ringing sound in the ear; some people hear it as a cricket sound, others hear kind of a heart in the ear. Each one of those sounds can indicate different pathologies that are going on. Noise exposure types of tinnitus are a byproduct of damage done to the little hair cells that are in your cochlea. Every time those hair cells are bent, it sends a signal up the hearing nerve. These cells are rotated in a way that the hairs that sounds reach first are tuned to high frequencies. When you get a lot of loud sounds coming in, hitting those high frequency hair cells first, they’re being bent over, and they can’t recover because of the damage, so they constantly send that high-pitched signal to the nerve.”

Another cause of tinnitus is acoustic neuroma, which is, accord ing to Dr. Lenz, “A bad bear; like a tumor located on the hearing nerve.” She continues, “The bundles of nerve fibers around the outer rim of the hearing nerve are the high-pitched nerves, so when the acoustic neuroma presses on that nerve, again, you have high-pitched ringing.”


Audiograms
The Sound of Silence

An audiogram is a graphical representation of how well a certain person can perceive different sound frequencies. These are used by audiologists and other hearing professionals to help chart and detect hearing loss. On the chart, sound frequencies are labeled across the top axis, while the vertical axis measures the decibel level (dB) of sounds. Thus, the audiogram provides a graphical depiction of the softest level sound you can hear at various frequencies.

The left chart would be typical of someone with normal hearing – the dotted red line represents the cutoff for normal hearing in adults, meaning that for each frequency tested, you can hear sounds at or under 20dB. Note that the circles represent the right ear, while the Xs represent the left ear. The right chart would be typical of someone with moderate high frequency hearing loss, and is typical of noise damage. The softest sound you could hear at 4000Hz, for example, would be 50dB. Note how the hearing loss dips in the frequencies where consonants are heard (k, f, th, s). Conversing in anything but perfect listening conditions will result in difficulty understanding.


Sound Solutions
Any type of constant ringing is best avoided, but how? According to Dr. Lenz, start off with a checkup. “What we recommend when we’ve identified hearing loss is an annual hearing check. If there is no hearing loss, you are exposed to loud noises, and you’re wearing hearing protection as you should, you can probably go every two years or until you notice a decrease in hearing.” Does insurance cover checkups? “It really depends on who you have the insurance through, but I don’t see a lot of insurance companies covering hearing tests, especially not what they consider routine hearing tests.”

It’s relatively easy to establish that hearing loss is no fun, but what are some steps to avoid it? Dr. Lenz suggests over-thecounter earplugs, earmuffs, and custom-fitted earplugs. “A lot of patients feel that the over-the-counter earplugs tend to be uncomfortable, and the ear muffs can be quite hot,” she says. “Both types – earmuffs and earplugs – decrease the amount of sound at different db levels for different dB levels.” This explains why the foam earplugs from the hardware store make everything sound so muddy. Is there a way around this? “The custom-fitted earplugs, the musician’s earplugs, attenuate at different dB levels, but it’s equal across the board, so everything is much more realistic.”

What is involved when getting fitted hearing protection? “The first visit is going to be where we take an ear impression, and that usually takes about 15 minutes,” says Dr. Lenz, who also takes patients through some additional measurements to ensure the best fit and function. A tube microphone is inserted into the ear, and sound pressure measurements are taken, both with and without earplugs. After a fairly quick process, your earplugs will arrive in approximately ten days. “When the ear protection devices come in, it’s just a matter of making sure that the person knows how to insert them correctly, so they get the best protection they can.”

With most manufacturers offering 15dB or 25dB cut, which will offer enough protection while still keeping things sounding natural? Mr. Stroud suggests the 15dB cut. “Generally the 25 is too much. Unless you’re just dreadfully loud, there’s no reason to go that much. The 15dB cut sound great. They just take a little bit of adjustment.”

Last time we checked, audiologists still had to pay their own mortgages, so none of this is free, but what can you expect to pay for a pair of fitted plugs? Dr. Lenz said, “Around $150,” which matches up with Peter’s estimate of, “$100-$150 out the door.” Let’s face it, $150 will barely get a decent delay these days, and, compared to the alternatives, seems like a rather paltry amount to ensure that you will be enjoying music until a ripe old age.


To get an idea of what kinds of loud noises we are exposed to everyday, we went out with a dB meter and took a few musician-specific measurements, then added in some more common, day-to-day levels. The results were surprising.

Weakest sound heard 0dB
Typical conversation (3-5’) 65dB
Acoustic guitar (3’) 75dB
Thursday morning at the local Guitar Center 77dB
Telephone dial tone 80dB
Ambient car noise at 60 mph 86dB
Train whistle at 500’ 90dB
Level at which sustained exposure may lead to permanent hearing loss 90dB
5-watt tube amp (3’) 105dB
Lawn mower 107dB
Saturday afternoon at Guitar Center 108dB
Level inside a car traveling at 60 mph with the windows down 114dB
Car stereo 120dB
Level at which pain begins 125dB
Rock concert 130dB
Jet engine at 100’ 140dB
Death of hearing tissue 180dB


Loudest sound possible 194dB

Some statistics are from a study by Marshall Chasin , M.Sc., Aud(C), FAAA, Centre for Human Performance & Health, Ontario, Canada.


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