I am 72 years old and i had tuned my room 100 resonators by ears in a one year period...Use what you have for what you have : your ears/brain...
Perceiving sound is not explained by frequencies Fourier linear analysis , it is way more complex... If the window of your house is more narrow now than it was before because you decrease his wall dimensions , you can anyway see and RECOGNIZE the scenery as well than before... Why ? it is because you had learn how to perceive sensible qualities of sound which cannot be described and understood only by mere references to the frequencies responses maps...There is other acoustic, psycho-acoustic factors...And concepts cannot be erased by a decreased frequencies perception...We can think with half or almost no brain , in the same way we can listen and conduct an orchestra in old age with a lower high frequencies perceptive ceilings... For sure we need some level of frequencies perception and not a too low level ...Nobody want hearing aids... But old age of healthy people dont erase music and sound PERCEPTION...
My wife with better measured hearings than me could not have tune my room because she never learn how to perceive sounds in a small room... Perceiving is also conceptualization...Without concept you cannot identify the song of a bird as the "song of a bird" only as an unknown noise...
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«We see sounds , we do not only hear them» Anonymus acoustician to a deaf patient learning echolocation