Your sense of hearing is a delicate instrument that is exquisitely sensitive to the nuances of sound. While our senses tend to be dominated by vision, hearing is subtly pervasive, affecting our consciousness and even our emotions.
A key part of that is the ability to discern pitch. If you're lucky enough to enjoy normal hearing, you can detect differences as small as 1-2 Hertz in the mid-frequency range (around 1000 Hz). Considering that the notes C and D are about 32 Hz apart, that's a fine margin.
That, however, varies somewhat depending on a few things including age. Generally we are better at picking differences in the lower registers.
People with musical training are typically more sensitive to pitch, which might be a curse when listening to a clumsy player.
Certain types of hearing loss can damage both your sense of pitch and volume.
It is also affected by the mix of sounds present, because sounds almost always include harmonies, disharmonies and random extraneous noises. The most beautifully played notes of a musician get shuffled around as they bounce back and forth against objects such walls, chairs, floors and other people.
Considering what can be a tortuous route from player to ear, it's remarkable we can make any sense of it at all.
As sound travels through the hearing mechanisms of the outer ear, the canal and the eardrum, it is further modified. Even the tiny middle ear bones called the ossicles have a resonant frequency, which affects the sound. But, at least for an individual, this sound imprinting is mostly constant.
The real magic of pitch perception begins in the small snail-shell-like structure called the cochlea, which is about the size of a pea. The spiral, fluid-filled channel through the cochlea is lined with microscopic hair cells that are waggled by passing sound waves.
The wide end where sound enters is most sensitive to high frequencies, while those at the far - or narrow - end, are most sensitive to low frequencies. They're arranged like the keys on a piano, stretching from high frequencies at one end, to low at the other.
Signals from the cochlea are sent into the auditory cortex in the brain, which interprets them as different pitches. How the brain does that, is one of nature's wonders. Somehow, the entire tangled plot is assembled into a cohesive experience we call music.
On July 15, your Ask Fuzzy columnist will be teaming up with the Canberra Symphony Orchestra to present Music To Your Ears, a fun and interactive show for all ages, normal, deaf and hearing impaired.
Free tickets available at https://unchartedterritory.com.au/etn/music-to-your-ears-science-of-hearing-though-classical-music/
Listen to the Fuzzy Logic Science Show at 11am every Sunday on 2XX 98.3FM.
Send your questions to AskFuzzy@Zoho.com Twitter@FuzzyLogicSci
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