Copper has an exchange program with selected magazines, where we share articles, including this one, between publications. This one's from Switzerland's AAA Magazine.
Conscious listening to music is always linked to previous experiences of listening to music. After describing the functions of the brain in relation to hearing, I will explain how strongly experiences and expectations can influence our hearing.
The Brain Needs a Lot of Energy
Our brain accounts for only two percent of our body volume. However, it consumes 20 percent of our body's energy. That is an average of 500 calories per day. During intense thinking, this can increase by 200 calories. The brain also works at night because it maintains communication between nerve cells and their functions. This means that the synapses between brain cells require constant energy to remain functional. Among many other things, the brain must filter the sound waves that reach the ear according to their meaning, and make them recognizable.
The Brain Constantly Evaluates
Our brain helps determine whether we evaluate daily experiences positively, or critically, and tend to devalue them. According to many studies, both playing and listening to music has a positive influence on brain activity. Music keeps the brain active. Anyone who consciously and joyfully plays and/or listens to music takes a positive influence on his thought processes. We create our access to the world through our active perceptions. For example, taking an LP out of its sleeve, placing it on the turntable, and putting the tone arm on the record is associated with haptic processes that reward us with anticipation of the sound to come.
Processing of Auditory Signals in the Brain
Hearing is a complex process. Different sound waves with different frequencies reach our ear canal and eardrum. These physical vibrations are then “evaluated” by the cochlea by its hair cells according to their frequencies, with shorter hair cells responding to higher frequencies. From there, sound is transmitted to the brain in the form of electrical signals. The electrical impulses created by the hair cells gives the brain the auditory impression of hearing sound.
Even sound differences of 0.6 milliseconds between the two ears can be perceived, and allow us to determine the location from which the sound is coming.
Without this ability, we would not be able to hear a spatial stereo effect with two speakers. The brain's ability to perceive such tiny sound differences also enables us to perceive the smallest disturbances in sound – even if they do not enter our consciousness. This is because our brain perceives such differences and tries to integrate them into our overall sensory experience.
The primary auditory cortex processes the information coming from the cochlea. However, these signals are also processed in the secondary and tertiary auditory cortex with experiences from other sensory systems and from memory. This means that every sound we hear is linked to previous experiences and automatically to expectations.
Anatomy of the human ear. Courtesy of Wikimedia Commons/Lars Chittka, Axel Brockmann.
Emotional Aspects as the Basis of Hearing Experience
This can be further explained by listening to speech. We can easily distinguish between similar syllables such as "lake” and "take.” Children learn the difference between “bad” and “dad” at an early age. These syllables are recognized in the left hemisphere of the brain. However, it is only through the recognition of the tonal quality of a specific person’s voice, and the sentence structures used, that the right hemisphere of the brain enables words or sentences to be clearly associated with specific meanings.
Both hemispheres of the brain allow analytical hearing based on stored life experiences, and at the same time create emotional involvement in hearing. There are voices that are perceived as pleasant or unpleasant due to one's own socialization. We listen emotionally with the right hemisphere of the brain. And the music that one person likes may not be enjoyed by or even understandable to others. Listening to music requires emotional access. For some people, for example, this may manifest itself as a love of early punk rock, while others may find this music absolutely terrible.
In any case, these feelings are guided by the subjective emotions with which the music was and is listened to. Similar contrasts can be found in free jazz – and 12-tone music is still waiting to become part of everyday classical music in concert halls.
This YouTube video from the National Institutes of Health (NIH) shows the pathway of sound from the outer ear to the brain:
Variability of Hearing
I experience how we influence our hearing with our brains every time I listen to music at home and then drive in my car and turn on the music. The difference in sound between the two systems is significant – and yet, after a short time in the car, I can enjoy listening to music and discover new music. The reduced sound quality in the car soon ceases to bother me.
The brain adapts the sound we hear to our listening habits – to a certain extent. However, listening to music on a lesser-quality car radio system can lead to listening fatigue, because the brain has to work constantly.
On the other hand, our brain can also easily adjust to and welcome the sound of a very good audio system. And when listening to a new audio sound system for the first time, say, at a friend’s house, we often consciously or unconsciously compare it with our own system. It takes 15 to 30 minutes before we can consciously recognize the qualities of the other system.
Expectations for Better Sound
In my experience, high-end listeners are constantly looking for new (and possibly better) components for their systems. The expectation that a potentially better sound can be achieved drives this search. It is exciting when friends with good systems and good hearing recommend something, whether a cable, the “ultimate” remastering of an old recording at a price of $200, a new phono cartridge that allows you to hear the smallest details in an LP in a way you never heard before, and so on and so forth. As every audiophile knows, it is always possible to invest into new equipment in one’s audio system.
What I find exciting is how these demonstrations at friends' houses, or dealers or audio shows, leave an impression on our minds and often inspire new purchases. The expectation of better sound is created within our brains, especially when it is reinforced by a group of friends who are listening along with us. This often has to do with focusing on what we expect. We hear what we want to hear.
We live in a consumer society that thrives on constantly creating new needs through marketing and advertising, promising to satisfy them. We hear the same kinds of sentiments in high-end audio: “I heard my music in a completely new way!” “Suddenly, details came to light that I had never noticed before!” “The dynamics and soundstage are incredible!” And every reviewer has a repertoire of favorite catchphrases. I like it best when critics end a review by saying how much they would have liked to keep the product they reviewed.
Frequency mapping of the auditory cortex. The numbers correspond to the cochlear frequency spectrum, shown in kilohertz. Courtesy of Wikimedia Commons/Chittka L, Brockmann.
Sound Improvements
Despite these reservations, I know there are products out there that can improve the sound of an already-excellent system. As audiophiles and music lovers, that's what drives us.
Something as basic as a lower-impedance (electrical resistance) speaker cable can make the music sound better, since a higher cable impedance requires more voltage to achieve the same volume, and the brain perceives a higher volume as better sound. [The oldest speaker demo trick in the book is to play one speaker louder than the other one in the dealer showroom and the listener will tend to think the louder speaker is better – Ed.]
During listening comparisons done in public, I sometimes wonder whether the clearly audible improvements we hear under these situations would also be detected at the same volume level in a blind listening test, or whether we are “hearing” the brain's reactions to our expectations. Or, what is rightly perceived as a different sound on first listening may turn out to be a deterioration in sound quality after a component or loudspeaker is purchased and listened to at home. Or, perhaps a sound that was previously heard as an improvement, due to the listener's expectations in the brain, turns out to be identical and not an improvement after all.
It has been said that only when a new speaker or component can be clearly recognized three times in a row in a blind test does it actually sound different. And let’s not forget that a change in sound does not necessarily mean an improvement in sound.
The Brain Adapts to the Sound
In many peoples’ opinions, new components and loudspeakers in an audio system first need to be broken in, although when it comes to phono cartridges, some experts believe they need break-in time, while others feel that the sound of a brand-new pickup system is the best possible. Some reviewers recommend 100 hours of break-in time even for cables. On the other hand, some feel that there is no such thing as break-in and that the “change in sound” is just the listener getting used to the new item in their system.
It is true that the brain listens with expectations. It makes sense to admit this to ourselves. We ultimately get used to the sound of a system or any part of it, whether the cartridge, amplifier, or speaker. This habituation is clearly evident to any owner of a tube amplifier who, after years of enjoying the wonderfully warm sound of their amplifier, has to replace the power amplifier tubes. Suddenly, the sound is much brighter and clearer. The brain now has to get used to it again.
Or the capacitors in the preamplifier and power amplifier may have gone out of spec, causing the sound to become darker. The speaker cones may have lost their original firmness, or become porous, and slowly change in sound.
This raises the perhaps cynical question of whether high-end listening enjoyment is ultimately more determined by the brain than by the equipment itself. Does the purchase of a new component always confirm the subjective nature of our listening experiences? Or is buying a new component just a “research object” for our subjective listening habits?
None of these considerations should influence our enjoyment of listening to music, though, because happiness is a subjective category. Ultimately, we want to experience the joy and satisfaction of listening to music forever.
******
The following explanation of how the ear and brain gather and process sound is translated and edited from the website Dasgehirn.info (thebrain.info), used here with the kind permission of author Arvid Leyh. For the complete original article, please click on the following link:
https://www.dasgehirn.info/wahrnehmen/hoeren/hoeren-mehr-als-nur-schall-und-schwingung
It's in German but can be translated into English using Google Translate.
Hearing – More Than Just Sound and Vibration
The task of collecting sound is performed by the auricle of the outer ear. It forms a kind of funnel and directs sound vibrations into the ear canal, from where they reach the middle ear. Sound waves hit the eardrum at the end of the ear canal and cause it to move, which in turn causes the three ossicles, or bones in the middle ear, to vibrate. Then the cochlea, located in the inner ear, converts this mechanical input into neural impulses, which then travel along neurons along the auditory pathway to the brain. Simple vibrations become the wonderful diversity of sounds we hear!
The auditory signals are transmitted to the brain stem – a kind of distribution station from which parallel signal paths run. Near the end of the auditory pathway, the thalamus transmits the information to the primary auditory cortex in the temporal lobe. It is mainly thanks to this "auditory center" that we are able to consciously perceive the acoustic diversity of the world.
But what makes the small but crucial difference between whether the neurons in our heads are processing a Beatles song or our partner's declarations of love? Different groups of neurons in the auditory cortex respond to different frequencies, and different sounds each have their own characteristic frequency spectrum. Human speech, for example, ranges from 80 Hz to 12 kHz. The auditory cortex uses these differences to pre-sort information: it distinguishes human words from other acoustic sources and forwards such information to other groups of neurons and areas of the brain, whether the roar of a jackhammer or the sound of a Beethoven sonata.
When we listen to music, the auditory cortex is only the entry point for the sonic information. Many other areas of the brain come into action to process experiences and associations related to our experience of music. What these are and to what extent we experience them varies from person to person. When we listen to a string quartet, for example, the brain also links the acoustic information with the visual images of violinists and cellists that we have stored in our memory, as well as with the emotions and memories that we associate with the music. So it's no wonder that music can send a pleasant shiver down your spine or bring tears to your eyes, or that teenagers are overcome with joy at a concert by their favorite band.
Header image courtesy of Shopify AI.
0 comments