The Hearing Aid

The Equal Temperament

Chapter 26: The Hearing Aid

The hearing aids were small, smaller than Clara had expected, each one a crescent of beige plastic no larger than the first joint of her little finger, fitted behind the ear with a thin wire that curved down and forward into the ear canal, the wire terminating in a silicone dome that sat in the canal's opening and delivered the amplified signal to the tympanic membrane, and the aids were digital, were computers, were processors that received the acoustic signal through a microphone, converted it to a digital representation, applied algorithms that selectively amplified the frequencies where Clara's hearing was diminished while leaving the frequencies where her hearing was normal unchanged, and then converted the processed digital signal back to an acoustic signal and delivered it through a miniature speaker into the ear canal, the whole process occurring in approximately six milliseconds, six thousandths of a second, a delay that was, according to Dr. Chau, imperceptible to most users.

Clara was not most users.

Dr. Chau had fitted the aids on a Thursday morning in April, in the consultation room on the fourth floor of the medical building on Morrison Street, and the fitting had been careful — the audiogram loaded into the programming software, the amplification curve shaped to Clara's specific loss, the frequencies above 6,000 hertz boosted by the amount the audiogram indicated was necessary, the gain at 8,000 hertz set to compensate for the 50-decibel deficit in the right ear and the 55-decibel deficit in the left — and Dr. Chau had placed the aids on Clara's ears and turned them on, and the world had changed.

Not improved. Changed.

The first thing Clara heard was the ventilation system. The HVAC in Dr. Chau's office, which Clara had heard before as a low hum at approximately 120 hertz, was now accompanied by a high-frequency component — a hiss, a sibilance, a presence in the upper frequencies that the aids were amplifying, the sound of air moving through ducts at a velocity that produced turbulence, the turbulence generating broadband noise that extended into the frequencies above 6,000 hertz, and this noise, which Clara's unaided ears had not been hearing for months, was now present, was now audible, was now part of the acoustic environment of the consultation room, and the noise was — Clara searched for the word — the noise was intrusive.

"The aids will take some adjustment," Dr. Chau said, and Clara heard Dr. Chau's voice differently — the consonants sharper, the sibilants brighter, the "s" sounds in "some" and "adjustment" carrying a crispness that Clara had not heard in months, the high-frequency components of speech restored by the amplification, and the restoration was — Clara listened to the restored consonants — the restoration was accurate, was approximately correct, was something like what consonants had sounded like before the hearing loss, but the something-like was not the thing itself, was a reproduction rather than an original, a photocopy rather than a document, the consonants carrying a quality that was not natural but processed, not acoustic but electronic, the sound passing through the six-millisecond delay of the digital processing and emerging slightly altered, slightly different from the sound that would have reached Clara's ear if the ear itself had been capable of hearing it.

"Try speaking," Dr. Chau said.

"The S sounds are sharp," Clara said, and heard her own voice — her own voice — differently, the sibilants in "sounds" and "sharp" arriving at her ears with the same processed crispness, her own speech sounding foreign to her, the voice she had been hearing from inside her head for fifty-two years now arriving at her ears through a digital intermediary, and the intermediary was — was present, was audible as a quality, a coloration, a tinting of the sound that was not the sound itself but an addition to the sound, the way a colored filter over a lens is not the light itself but an addition to the light.

Dr. Chau adjusted the programming. Reduced the gain above 8,000 hertz by two decibels. The sibilants softened. The hiss of the HVAC receded. The world became slightly less sharp, slightly less bright, slightly more like the world Clara was accustomed to hearing.

"Better," Clara said.

"We'll refine the settings over the next few weeks. The brain needs time to adapt. You've been hearing without these frequencies for — how long since you first noticed the loss."

"Seven months."

"Seven months. Your auditory cortex has adapted to the reduced input. It's remapped. The aids are providing input that the cortex hasn't been processing, and the cortex needs to relearn how to process it. Give it two weeks. Wear the aids during the day. Start with quiet environments and gradually move to noisier ones."

Clara left the office wearing the aids. She walked to her car and sat in the driver's seat and closed the door, and the car was — loud. Not the engine, which she had not started, but the environment — the parking garage, the echoes, the distant sound of a car starting on another level, the hum of the fluorescent lights in the garage, all of these sounds arriving at her ears with their full frequency content for the first time in months, and the fullness was overwhelming, was too much, was the acoustic equivalent of walking out of a dark room into bright sunlight, the sensory system unprepared for the volume of information it was receiving.

She turned off the aids. The small buttons on each device clicked under her fingertips, and the world contracted, returned to the world she had been living in, the world with the reduced upper frequencies, the world that was warmer and darker and more bass, the world that was familiar, that her brain had adapted to, that was — Clara acknowledged this — that was comfortable, the comfort of the known, even if the known was diminished.

She sat in the car with the aids off and thought about what she had heard. The aids had restored the upper frequencies. The aids had returned the consonants and the sibilants and the hiss and the high-frequency components of every sound in the environment. The aids had done what they were designed to do. And the doing was — was not wrong, was not bad, was not uncomfortable in a medical sense — but was different, was altered, was the introduction of a mediator between the sound and the ear, a processor that stood between the world and Clara's perception of the world, and the processor changed the perception, not by much, not dramatically, but enough that Clara could hear the processing, could detect the artifact, the six-millisecond delay, the digital coloration, the quality that was not the quality of unamplified sound but the quality of amplified sound, and the two qualities were not the same.

She drove home with the aids off. She parked and went inside and sat at the kitchen table and looked at the aids in their case — the case was small, hinged, lined with velvet, the two devices sitting in their molded compartments like instruments in a case, like the tuning fork in the bag — and she thought about what the aids would mean for her work.

She took the fork from the table and struck it. A440 without the aids. Clear, true, present. The fundamental and the partials rising through the harmonic series, fading above the tenth, the familiar decay, the familiar edge.

She put the aids on. She turned them on. She struck the fork again.

A440 with the aids. The fundamental was the same — 440 hertz was in the range where the aids did not amplify, where Clara's hearing was normal, and the fundamental was unchanged, unprocessed, unaltered. But the upper partials — the partials above the sixth or seventh, above 3,000 hertz — the upper partials were different. They were louder. They were present in a way they had not been present for months. Clara could hear the ninth partial at 3,960 hertz, could hear the tenth at 4,400, could hear — she listened, searched — could hear something at 5,280, the twelfth partial, a whisper of tone that was not the natural whisper of a partial heard by a healthy ear but the amplified whisper of a partial boosted by the hearing aid, the partial present but processed, audible but artificial, the sound arriving through the digital intermediary rather than through the direct chain of air and eardrum and ossicles and cochlea.

The partial was there. But it did not sound the way partials had sounded before the hearing loss. It sounded like a partial heard through a hearing aid. It sounded like a partial that had been converted from analog to digital and back to analog, the double conversion introducing the artifact, the coloration, the quality that a tuner's ear — an ear trained to hear the finest differences in pitch, the subtlest variations in timbre, the most minute deviations from correct — would detect.

Clara held the fork and listened to the amplified partials and thought about whether she could tune with this sound. Whether the aids could restore enough of the upper-frequency hearing to allow her to tune the top octave by ear — by aided ear — without the Korg, without Yuki, without the compensations. Whether the amplified beats between the upper intervals would be accurate enough, clean enough, uncolored enough, for Clara to count them and judge them and act on them the way she had acted on the unaided beats for twenty-eight years.

She went to the Knabe. She sat at the bench with the aids on and played C7 and C8 together, the octave at the top of the piano, the octave that had been the test case for the hearing loss, the octave where the beats between the partials were in the territory above 6,000 hertz that the aids were amplifying.

She heard the octave. She heard the two notes sounding together. She heard — something. She heard a brightness, a presence in the upper frequencies that had been absent for months, the aids restoring the energy above 6,000 hertz, and the restoration included the beats, the interactions between the partials, and Clara listened for the beats and heard — beats. She heard a pulsing, a wavering, in the upper frequencies. The octave was beating. The octave needed adjustment.

She took the lever — the lever was on the table, she had not put it in the bag yet, had kept it close, had not been ready to stop holding it — and she seated it on the C8 pin and turned, and the pitch changed, and she struck the octave again, and the beats — she listened through the aids, through the processing, through the six-millisecond delay — the beats were slower. She adjusted again. The beats were slower still. She adjusted, carefully, a fraction of a degree, and struck the octave and listened.

The beats were gone. Or the beats were too slow to count. Or the beats were present but masked by the processing artifact, by the coloration that the aids introduced, and Clara could not tell which — could not distinguish between a clean octave and an octave whose beats were hidden by the noise of the amplification — and this inability to distinguish was the problem, was the reason Dr. Chau had said "for fine pitch discrimination, it's less clear," was the limitation that Clara had feared and was now confirming.

The aids could restore the volume. The aids could make the upper frequencies audible again. But the aids could not restore the clarity. The clarity depended not just on the volume of the signal but on the signal-to-noise ratio, the ratio between the information the ear needed and the noise the ear received, and the aids increased both — increased the signal and increased the noise, the processing artifact present at every frequency the aids amplified, the coloration constant, the digital intermediary always there, always between the sound and the perception, and the intermediary was — for speech, for conversation, for the daily sounds of life — the intermediary was acceptable, was useful, was a net improvement, the restored consonants and sibilants worth the slight coloration, the trade fair.

But for tuning the intermediary was not acceptable. For tuning, where the difference between correct and incorrect was measured in cents, in fractions of hertz, in beats so slow they were almost not beats but texture — for tuning, the coloration was too large, the artifact too present, the noise floor too high. The aids could help Clara hear the world. The aids could not help Clara tune the world.

She took the aids off. She set them in the case. She struck the fork without the aids.

A440. Clear, true, present. The familiar sound. The unprocessed sound. The sound that arrived at Clara's ears through the direct chain, air to eardrum to ossicles to cochlea to nerve to cortex, the chain that was weakening at the cochlear link but that was, in the range of the fork, in the range of the fundamental, still functional, still direct, still unmediated.

She closed the case. She set the case on the table beside the fork. The aids and the fork. The amplification and the reference. The device that changed the sound and the device that did not.

She would wear the aids. She would wear them for speech, for conversation, for the sounds of daily life, for the consonants and the sibilants and the birds and the high-frequency components of the city that she had been missing. She would wear them because they helped, because the world was fuller with them, because the aided world was closer to the world she remembered than the unaided world was.

She would not wear them for tuning. For tuning she would use the ear she had — undiminished in the middle, compromised at the top — and she would use the Korg for the top octave, and she would use Yuki for the concert pianos, and she would continue the compensations that had become part of her practice, the leaning, the harder striking, the checking, the hybrid approach that produced tunings that were correct by the combined standard of the ear and the device.

The aids were for the world. The ear was for the piano. The distinction was clear. The distinction was the distinction between hearing and tuning, between receiving sound and judging sound, between the passive act of perception and the active act of discrimination, and the aids could assist the passive and could not assist the active, could help Clara hear the piano but could not help Clara tune it.

She picked up the fork and held it without striking it. The steel was cool. The A was stored in the tines, potential, waiting. She held the fork and the aids sat in their case on the table and the rain fell on the roof and the house was quiet and Clara sat in the quiet and held the reference and thought about the difference between hearing and tuning and between the world and the piano and between what the aids could give her and what they could not.

The aids could not give her back her ear. Nothing could give her back her ear. The ear was the ear she had. The aids were a tool that worked for some things and not for others, the way the Korg was a tool that worked for some things and not for others, the way every tool worked for some things and not for others, and the tuner's job was to use each tool for the things it was good for and to know the limits of each tool and to work within those limits and to accept, as equal temperament demanded, that perfection was not available, that every tool was imperfect, that every system was a compromise, and the compromise was the work.

She set the fork on the table. She opened the aid case and looked at the two small devices, beige and discreet and technologically sophisticated, the product of decades of engineering, miniature computers designed to compensate for the aging of the human cochlea, and she closed the case and put it in the bag, in the pocket beside the Korg, the two devices side by side, the two electronic tools that supplemented the one organic tool that was Clara's ear, and the bag held all three — the devices and the lever and the mutes and the fork — the complete toolkit of a tuner who was adapting, who was compensating, who was working within the limits of what she had.

She went to bed. She did not strike the fork again. She did not put on the aids. She lay in the dark and listened to the house with her unaided ears, the ears that heard the furnace and the rain and the refrigerator and the settling of the foundation, the sounds that were in the range where the aids made no difference, the range where Clara's hearing was normal, the range where the world was the world she had always heard, unmediated, unprocessed, hers.

She slept in the world she had.