Hear Things: Frequency, Vibration & Audibility

  • Thread starter toesockshoe
  • Start date
In summary: While the nominal range is 20Hz to 20KHz, the upper and lower ends can start to degrade at different points depending on age and other factors. He also mentions the equal-loudness contour and how human hearing is less sensitive at lower frequencies. He clarifies that there is no hard limit for what frequencies can be heard and that even at very low frequencies, you may not hear a tone but rather individual pulses. This can be tested with a function generator and loudspeaker. In summary, the audible range is not a strict cutoff and varies between individuals, with some being able to hear a wider range of frequencies than others.
  • #1
toesockshoe
265
2
I know that the audible range is 20Hz to 20000 Hz... does this mean if give a string a vibration such that it has a frequency of 20Hz... it will cause a vibration in the air with a equal frequency and thus make it audible? Does this also mean that a string with 19 Hz will be inaudible?
 
Physics news on Phys.org
  • #2
Human hearing range is nowhere near that sharply defined. Yes, a 20hz string vibration is what we hear as 20Hz. The starting point for degraded hearing at the upper and lower ends is NOMINALLY 20Hz to 20KHz but the actual degradation points vary by individual. As we get older, the upper end starting point in particular drops off. Some people for example will be born with an upper end starting to degrade at 18KHz and dropping off such that they don't hear anything above 20KHZ but when they are 95 the degradation might start at 15KHZ and drop to nothing at 16KHz. These are just made up examples, but you get the idea, I assume.
 
  • #3
400px-Lindos1.svg.png
This is a standard ear sensitivity curve. See also https://en.wikipedia.org/wiki/Equal-loudness_contour.
 
  • #4
phinds said:
Human hearing range is nowhere near that sharply defined. Yes, a 20hz string vibration is what we hear as 20Hz. The starting point for degraded hearing at the upper and lower ends is NOMINALLY 20Hz to 20KHz but the actual degradation points vary by individual. As we get older, the upper end starting point in particular drops off. Some people for example will be born with an upper end starting to degrade at 18KHz and dropping off such that they don't hear anything above 20KHZ but when they are 95 the degradation might start at 15KHZ and drop to nothing at 16KHz. These are just made up examples, but you get the idea, I assume.
Alright, but you get my point... if an individuals hearing range IS defined to be 20Hz to 20KHz... they he would be able to hear a 20Hz string but NOT a 19 Hz string right? (again... assuming that some arbitrary individuals hearing range is 20Hz to 20KHz).
 
  • #5
toesockshoe said:
Alright, but you get my point... if an individuals hearing range IS defined to be 20Hz to 20KHz... they he would be able to hear a 20Hz string but NOT a 19 Hz string right? (again... assuming that some arbitrary individuals hearing range is 20Hz to 20KHz).
Sure, if things actually worked that way then yes that is they way thing would work but my point is they DON'T work that way. Nobody's hearing is such that they can hear one frequency perfectly and a small frequency different from that not at all and no "definition" you create is going to change that fact.
 
  • #6
toesockshoe said:
Alright, but you get my point... if an individuals hearing range IS defined to be 20Hz to 20KHz... they he would be able to hear a 20Hz string but NOT a 19 Hz string right? (again... assuming that some arbitrary individuals hearing range is 20Hz to 20KHz).
Wrong. No such hard limit exists. If you look at the curve in post #3, you will see, that the ear is progressively less sensitive below 1000Hz, and the sensitivity decreases fast when you get to about 20Hz. The curves stop at 20Hz and 20kHz because outside these frequencies it is hard to get good aural measurements.
 
  • #7
Svein said:
Wrong. No such hard limit exists. If you look at the curve in post #3, you will see, that the ear is progressively less sensitive below 1000Hz, and the sensitivity decreases fast when you get to about 20Hz. The curves stop at 20Hz and 20kHz because outside these frequencies it is hard to get good aural measurements.
alright got it.
 
  • #8
phinds said:
Sure, if things actually worked that way then yes that is they way thing would work but my point is they DON'T work that way. Nobody's hearing is such that they can hear one frequency perfectly and a small frequency different from that not at all and no "definition" you create is going to change that fact.

understood!
 
  • #9
toesockshoe said:
Does this also mean that a string with 19 Hz will be inaudible?

no, you hear ALL the way down as low as you care to go ... the difference is that from around 20 - 25 Hz and lower in frequency, you no longer hear a tone, rather you hear the individual pulses.
So at say 1Hz you hear a pulse once a second, at 0.1 Hz you hear a pulse once every 10 seconds

This is quite easy to experiment with a function generator that has a good low frequency range into a loudspeakerDave
 

FAQ: Hear Things: Frequency, Vibration & Audibility

1. What is frequency and how does it relate to hearing?

Frequency refers to the number of sound waves that pass through a specific point in one second. It is measured in Hertz (Hz). Our ears are able to detect frequencies between 20 Hz and 20,000 Hz, with higher frequencies being more audible to younger individuals.

2. How does vibration play a role in our ability to hear?

Vibration is an essential component of sound. When an object vibrates, it creates sound waves which travel through the air and eventually reach our ears. Our ear drums vibrate in response to these sound waves, and this vibration is converted into electrical signals that our brain interprets as sound.

3. What is the relationship between frequency and pitch?

Frequency and pitch are closely related, with higher frequencies corresponding to higher pitches and lower frequencies corresponding to lower pitches. This is why we perceive a high-pitched sound when a violin string is plucked and a low-pitched sound when a bass guitar string is plucked.

4. How does age affect our ability to hear different frequencies?

As we age, our ability to hear high frequencies decreases. This is due to the natural aging process and exposure to loud noises over time which can damage the hair cells in our ears responsible for detecting high frequencies. This is why many older individuals have difficulty hearing high-pitched sounds such as birds chirping or children's voices.

5. Can we hear frequencies outside of the normal range?

Yes, some individuals may be able to hear frequencies outside of the normal range of 20 Hz to 20,000 Hz. This is known as having a "supersonic" hearing ability. However, this is rare and not necessary for most day-to-day activities. Some animals, such as dogs and bats, have a wider range of hearing and are able to detect frequencies much higher than humans.

Similar threads

Can we hear beats between ultrasounds in the audible range?
Replies
23
Views
6K
Resonant Frequencies from Fourier Analysis
Replies
6
Views
2K
I How long would a tuning fork vibrate in vacuum?
Replies
27
Views
2K
Can a loud inaudible sound drown out audible noise?
Replies
5
Views
1K
Can We See Audible Frequencies?
Replies
2
Views
3K
Understanding the Fundamental Frequency f1 and Its Role in Sound Waves
Replies
6
Views
2K
How to solve this sound problem (minimum sampling rate required)
Replies
3
Views
1K
A Why does a guitar string "beat" as if it is out of phase?
Replies
11
Views
2K
B How does the ear distinguish multiple different pitches?
Replies
18
Views
2K
Exploring the Interaction of EM Waves & Molecular Vibrations
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top