Hearing Management

For Musicians, Sound Engineers and Music Lovers

At the Yellowstone National Park     Photograph: August, 2017

Ears are very important for listening to music.. It's an obvious fact, but are you really managing it properly? Nowadays, all PA/SR (amplification of sound by speakers in venues) is so loud that it hurts your hearing. Listening to music with headphones or earphones at excessive volume can cause permanent hearing damage. Some musicians exposed to high volume have geriatric hearing. Completely damaged hearing does not recover. Here, I would like to enlighten you to understand hearing and manage it properly by yourself.

What is hearing? (briefly）

Quoted from the website of Japanese Society of Otorhinolaryngology-Head and Neck Surgery.

Vibrations in the air cause the eardrum to vibrate and travel through small bones to the inner ear, which converts sound into electrical signals. Sound waves are vibrations of the membrane in the inner ear, and this membrane has outer hair cells that control the vibrations of the membrane and inner hair cells that convert the vibrations into electrical signals. Sound information converted into electrical signals is then processed in a complex way by the brain, and is recognized as language or music. Humans have adopted air vibrations and sounds as a means of communication, but how wonderful it is that they have sublimated this into the art of music!

If these hair cells are damaged by loud sounds and cannot be recovered by treatment, regeneration and repair of cells cannot be expected, resulting in hearing loss and tinnitus. The best treatment is to prevent hearing loss. Hearing declines with age, but how about accelerating aging yourself? Even if the appearance is young, the ears and contents are old, it's sad...

Hearing Test

A hearing test performed by an audiologist is recorded on an audiogram. The vertical axis is the volume of sound (sound pressure), and the horizontal axis is the pitch (frequency). Red 〇 is right, blue × is left. Bone conduction, which is actually heard through the bones, is also displayed in コ, but is omitted here for the sake of clarity. In this example, you can see that the high frequencies on the left are slightly less audible than the ones on the right. Hearing ability declines with age, but in general, for young people above 30, it is normal, and for middle-aged people above 40, it can be considered normal.

Hearing Test  -  Supplement for those involved in acoustics

Sound pressure is dBHL, not dBSPL. This is because human hearing has different sensitivities depending on the frequency, so the dBHL of the audiogram shows the minimum audible threshold for each frequency as 0 dB. 0dBSPL is a sound pressure of 20μPa, but at HL it is as follows;

By the way, there are actually quite a few doctors who claim to be otorhinolaryngologist who do not understand the basics (the relationship between dBHL and dBSPL), so please be careful.

The test frequency is the basic octave step, but hearing acuity above 8kHz is not measured because individual differences are too large. Classically, 20 to 20,000 Hz is written as the audible range, but this is for convenience. Actual range is about 16 to 18,000 Hz. Also, it is not hearing in the sense of hearing, but in the sense of feeling and cognition, it extends from low frequencies to high frequencies.

What happens when you have a hearing loss?

With normal hearing, sounds start to be heard at 5 to 10 dB, and become annoying at around 110 dB. Please understand that the hearing width (dynamic range) is about 100dB. However, in the case of the hearing loss shown above, low frequencies begin to be heard at 50dB and are perceived as loud at 110dB, so the dynamic range is 60dB. At 8kHz, the sound is barely audible at 80dB and sounds loud at 110dB, so the dynamic range is only 30dB. Then, you might think that it would be good to use a hearing aid to put the sound from 0 to 110 dB into this narrow dynamic range, but since the resolution is degraded with such ears, it is extremely noisy and difficult to hear. This is one of the reasons why hearing aids are difficult to wear and fit.

Around 4 kHz, the consonants of words are distributed. Therefore, in the case of elderly people whose frequency here is dropping, a phenomenon such as "I can hear the sound but I can't understand what does it mean." Since the processing speed of the brain slows down in the elderly, the phenomenon of  "unable to hear unless you speak slowly" also occurs. I have often experienced the complaint that I can hear the news of the announcer who speaks well on TV, but I do not understand what he is saying in dramas and variety shows. If you work in an environment where the sound is quite loud (you should protect your ears with earplugs) or if you are a rock musician who is always in a high volume environment, the 4kHz range will fall first, so the same situation applies.

Above left is the hearing of a 40-year-old drummer (mostly rock). There was a large valley in 4-6kHz, hearing loss, and complaints that daily conversation was difficult. Upper middle is the hearing of a 37-year-old drummer (jazz). Although there are differences in genres and acoustic exposure conditions, there is a big difference. Just as there are people who are strong and weak when it comes to alcohol, I think there are people who are strong and weak when it comes to loud noises. All concerts are so loud these days that it's deplorable, but there are people listening in the same place who get acute hearing loss and see a doctor, and others who don't mind at all.

Now, please pay attention to the results of the hearing test on the upper right. A patient complaining of bilateral tinnitus. 6kHz has valleys and hearing impairments. Normally above 4kHz it measures 8kHz and not 6kHz. Then this valley disappears from the graph and is diagnosed as almost normal. However, for some people exposed to loud sounds, 6kHz may drop earlier than 4kHz, so in the case of musicians, mixers, etc., it is often better to measure positively. In this case, the tinnitus frequency and the trough frequency at 6 kHz matched.

Beware of Low-tone Hearing Loss

In the last 20 years, there have been an extremely high number of cases of low-tone hearing loss. Most are mild to moderate. Symptoms include ear fullness, low-pitched tinnitus, ear pain, distorted sounds, double hearing, and out-of-tune. Dizziness and feeling of floating may be combined. In the past, it was classified as cochlear Ménière's disease, but it seems that various pathologies are mixed, and it is easily diagnosed as "sudden deafness". the situation continues. Please consider of sudden deafness as a disease of unknown cause in which severe deafness suddenly occurs on one side. Basically, low-frequency hearing loss and sudden hearing loss are considered separately. Here is the list of the problems.

　1. Inaccurate hearing tests have done, so there are cases of undiagnosed low-tone hearing loss.
　2. In hearing-sensitive cases such as musicians, there are cases in which mild low-tone hearing loss is overlooked and treated as normal.
　3. There are cases in which cochlear Ménière or endolymphatic hydrops could not be diagnosed.
　4. Sometimes, there is the complaining side and the sick side are opposite, but the doctor does not know it.
　5. Not only is the doctor unaware of the fact that the pitch is out of order and said "Because of your mind".
　6. Especially in the case of musicians, doctor have to explain about this disease and prognosis. Otherwise, the patient will panic, thinking that they will lose their hearing.
　7. It has decreased recently, but there are some doctors who only know eustachian tube stenosis when it comes to ear fullness.
      And they treat blindly continue the eustachian tube ventilation treatment.
　8. Some doctors think that the feeling of fullness is caused by patulous eustachian tube, and they treat it according to their own diagnostic criteria
　9. There are cases in which steroids are prescribed every time hearing deteriorates, and the amount and usage cannot be controlled.
10. There are cases that have been explained that even moderate to mild cases require hospitalization.
11. If stress or fatigue are involved, it is necessary to take care of it. Otherwise the disease cannot be cured.
12. Misinformation spread on the internet. But the patients see and input only bad things and fall into anxiety.
13. It depends on the news that the celebrity has sudden deafness.
      But most of them are thought to be Meniere's disease or low-pitched hearing loss, which should be distinguished from sudden deafness.
14. Sudden deafness is basically non-recurring. But many patients tell me that they suffer from sudden deafness many times.
15. Others

What is an ear monitor?

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Many musicians use the ear monitors now. In the past, they used to monitor and perform with the loud sound from the speakers placed in front of the stage. However, with this method, good monitors and sound cannot be obtained in large venues such as Budokan or domes, and the loud sound can damage hearing. Therefore, Van Halen's drum player, Alex Van Halen, consulted Mr. Jerry Harvey, who was the PA engineer in charge, "Is there any solution?", and the ear monitor was born. Hearing aid parts and technology are applied.

Since 2003, our clinic has set up a dedicated window for musicians and sound engineers, and as of August 2022, we have took over 1400 impressions. We do not use the same method to take ear impressions, according to the instrument, the way of singing, and the purpose of use.

Musicians are paired with a PA engineer to listen and balance each instrument. It should be noted that ear monitors are specialized for that purpose and most are not Hi-Fi. I've tested about 200 models in the past, and only a few of them can be called Hi-Fi for audio. If you choose just based on coolness of design you will regret it.

Ear monitors use a balanced armature type sound generator, which was originally used in hearing aids. Disadvantages are narrow bandwidth and poor sound quality. What's great about Jerry Harvey is that he divides the playback band into bass, midrange, and treble using by multiple drivers ,but the sound is fantastic.  His company JH Audio's 13Pro (ver.1) surpasses many high-end headphones, and the only thing that can match it is the STAX condenser type headphone. With this, the noise in the train is insulated, and you can hear delicate sounds of the Renaissance music completely.

However, when using ear monitors, you have to be more careful with the volume. Don't be a hearing loss maker. So sound engineers need to know the musician's hearing and have to take care of it. Please see this example. This case is 24-year-old male who made an ear monitor. Later, I was told from sound engineer that he suffered from left sudden deafness.

There is no way to give the same sound to the left and right to this hearing. Improper use of the left side can lead to further hearing loss. It is very important that advice from an otolaryngologist who is the expert of hearing and acoustics.

To make the ear monitor.

Hearing Management for Recording Engineers

Since the 1970s, recording monitors in the United States have become louder, and in Japan, mixing and track down are often performed at high volume. Prolonged exposure to high volume may cause temporary mild hearing loss. It is clear that working under these conditions will not introduce good results. I recommend that you manage your hearing and an appropriate volume.

Correct sound image localization cannot be obtained if the left and right hearing acuity is different. Also, if the hearing threshold for low and high frequencies is elevated, the sound may become v-shaped sound. It is very important to manage it by the otolaryngologist who is the expert of hearing and acoustics.

A strong request to those involved in PA/SR engineers

Almost all concerts or events, the sound level is too high, not even a rock concert. If you really want to listen to music, you should keep the volume down. In addition, there is no end to the number of people who have hearing damage at many concerts and events. Lower it by at least 10dB. Throw away your preconceptions and illusions, lower the level by 10 dB, hold a concert or event, and feel the response. Let's end the loud era.

For those who are hard of hearing (hurt their ears at a loud concert)

Always carry earplugs. There are two types of earplugs recommended by our clinic. One is Nagashima Medical's Onchi soundproof plug. For people working in factories, etc., it prevents loud noises but allows conversation. Control the volume by how deep you put it in your ear. The price is also cheap at ¥1200, and there are 3 sizes from 1 to 3. In addition, the earplugs on both sides can be connected with the attached string and hung around the neck.

The other is HearDefenders-DF HearPlug ZDF（E.A.R.Inc）. You can also control the volume by how deep you put it in your ear. The price is ¥3950, which is expensive, but the sound quality is relatively maintained. As I wrote at the beginning, the first and most important step is to prevent hearing loss and protect your ears.

What is a person with excellent hearing?

Some sensory organs are extremely sensitive. A dog's sense of smell is said to be 1,000,000 to 100,000,000 times that of humans. Sharks can detect one drop from 25m pool, and this pool contains one drop from drum. This dram contains only one blood drop. The Hadza people of Tanzania have a visual acuity of 11.0. In a normal visual acuity test, if the Landolt's ring (C shape) can be identified at a distance of 5m, it is 1.0. Visual acuity of 11.0 is 55m ahead, and they can see the break in this ring. In Africa, if a native people says someone is walking with a rifle in his right hand, no one can see it. It seems several Km ahead. After a while, we finally saw a man walking with a gun in his right hand

Well, what about people with excellent hearing (ear sensitivity)? This is the hearing test result of the best hearing person I know.

Since all the minimum sounds were heard, it was impossible to measure (↑marks. scale out). This person could even hear cars driving on the road in front of the hospital outside the soundproof hearing room. There is a difference of 30 dB or more in dynamic range between this person and a normal person, for example, a person with a hearing level of about 15 dBHL. This is the example of sensitivity is extremely good, but sensitivity and and resolution are different because acquired brain learning is added. I will write about perfect pitch on another occasion. For people with good hearing and high resolution;

1. He feels the four seasons through changes in the sound of the moisture (humidity) of the speaker cone paper.
2. He can detect the failure of the power supply unit of broadcasting station equipment.
3. He can find out where the distortion is occurring in the recording equipment.
4. When he listen the recordings, he can see microphone settings.
5. The recorded booth acoustics give him an idea of the size of the glass window in front and the size of the room.
6. Even if he is listening to the TV on the back, he can instantly know which hall the performance is in.
7. Problems with audio equipment are too obvious for him and he cannot talk with audiophiles.
8. When walking in a restaurant street, the high-frequency sound of the mouse repellent pierces his ears and voice comes out involuntarily.
9. And so on....

People with this type of hearing ability are considered as abnormal, so they live a lonely life until someone understands them. So, is this kind of hearing evolution? There may have been times when it was sensitive to slight changes in its surroundings and would be killed if it didn't feel "killing intent". We don't need such keen senses now, so if there were people like this, we could call them ancient people. Public address systems are commonly used at gatherings in gymnasiums and schoolyards. The original human ear was capable of hearing without a public address system. Many modern people may have grown up without thinking about listening carefully. A child walking slowly in the middle of the road and not noticing a car coming from behind is a normal evolutionary and adaptive child. However, even without innate ability, hammer inspectors who work at canning factories and hammer inspectors at railways can master it through acquired training. I can't help but think that human adaptability is amazing.

At the Kyoto     Photograph: November, 2014