Why do emergency detectors use high pitched sounds?

  • Thread starter newjerseyrunner
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In summary: Lower frequency alarms need bigger speakers to achieve same volume....it stands to reason that a higher pitched sound would be more effective since it will be heard over a greater range.In theory, because it is out of the range of the most commonly used frequencies. Usually apart from some bird songs there are not many sources for that range.This makes sense. In summary,-There is a practical reason for emergency alarms using a high pitched sound - it is out of the range of the most commonly used frequencies.-Lower frequency alarms need bigger speakers to achieve the same volume, so a higher pitched sound would be more effective.
  • #1
newjerseyrunner
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I know that as humans age their abilities to hear high pitched deteriorates, even if the rest of their hearing doesn’t. So why do emergency things like CO detectors use such a high pitched sound? I got to my in laws and their detector needed new batteries. Neither are hard of hearing but neither had any idea their detector was going off. Made me wonder if they’d even be able to hear it if it went off for real?
noises
 
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  • #2
Maybe because shrill sounds carry farther than lower frequencies?
 
  • #3
phinds said:
carry farther than lower frequencies?
Do they? Google "elephant communication."
 
  • #4
Bystander said:
Do they? Google "elephant communication."
Yeah, I googled around a bit. Turns out I apparently had it backwards.
 
  • #5
Shrill is maybe 1 or 2 kHz? That's well within the peak of human hearing.
 
  • #7
Smoke detectors aren't that high of a frequency. I believe they commonly use a frequency around 3 kHz.
 
  • #8
phinds said:
?

That's very low on in the range of human hearing:

You're misreading something. 1.76 kHz is two A's above middle C.
 
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  • #9
Vanadium 50 said:
You're misreading something. 1.76 kHz is two A's above middle C.
I'm just saying ... the human range of hearing goes up to 20KHz, so a couple of KHz is low on that scale. Maybe everything over a couple of KHz sounds high pitched but is still audible.
 
  • #10
phinds said:
I'm just saying ... the human range of hearing goes up to 20KHz, so a couple of KHz is low on that scale. Maybe everything over a couple of KHz sounds high pitched but is still audible.
In terms of octaves, the human range is 11 octaves with 2 kHz falling in the 7th octave.

Also, the (normal) human ear is most sensitive to the 2-5 kHz range, so it would make sense to place an alert tone in this range.
 
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  • #11
newjerseyrunner said:
So why do emergency things like CO detectors use such a high pitched sound?
Interesting question, which makes me think of many alarms clocks which also have (relatively) high pitched sounds. I wonder if it is beacuse it sounds more intense/is more annoying, so the listener is more inclined to take action or even wake up?

EDIT:
Janus said:
Also, the (normal) human ear is most sensitive to the 2-5 kHz range, so it would make sense to place an alert tone in this range.
Sounds like a good reason.
 
  • #12
LOL, nope, nope, nope.:smile:
newjerseyrunner said:
I know that as humans age their abilities to hear high pitched deteriorates, even if the rest of their hearing doesn’t. So why do emergency things like CO detectors use such a high pitched sound?
There is a practical reason for this, but it has little to do directly with the best range for human hearing...
Small, inexpensive piezo-based sound makers for low-cost consumer electronics happen to have that frequency range. You are not going to spend several dollars for a speaker-based sound maker in a product design, when you can use a simple sub-dollar piezo beeper instead... :smile:
 
  • #13
phinds said:
the human range of hearing goes up to 20KHz, so a couple of KHz is low on that scale.

Ah, here's the thing you are missing. Hearing is logarithmic. Each octave is a factor of two in frequency.

berkeman said:
There is a practical reason for this, but it has little to do directly with the best range for human hearing...

I suspect the reason the devices are inexpensive is because they are mass produced in the range that is best for human hearing.
 
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  • #14
Simple and solid state construction probably helps as well.
 
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  • #15
Vanadium 50 said:
I suspect the reason the devices are inexpensive is because they are massed produced in the range that is best for human hearing.
Just a commercial goodness coinkidink. :smile:
 
  • #18
newjerseyrunner said:
So why do emergency things like CO detectors use such a high pitched sound?
In theory, because it is out of the range of the most commonly used frequencies. Usually apart from some bird songs there are not many sources for that range.

In reality, it is what @berkeman wrote under that spoiler button...
 
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  • #19
Lower frequency alarms need bigger speakers to achieve same volume.
 
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  • #20
if i remember right the resonant frequency of the human ear canal is around 3khz, so I am guessing that has something to do with it as well..

i know when mastering a music track, its common to dip down the volume in that range.
 
  • #21
Rive said:
In theory, because it is out of the range of the most commonly used frequencies. Usually apart from some bird songs there are not many sources for that range.
Well, since birds already got mentioned - http://users.aber.ac.uk/rmm/urbansong.htm
 

1. Why does a high pitched beep occur?

A high pitched beep can occur for a variety of reasons, but it is often associated with electronic devices such as alarms, timers, and notifications. This is because these devices use a specific frequency to produce a sound that is easily heard by humans.

2. What causes a high pitched beep in the human ear?

When sound waves enter the ear, they vibrate the eardrum, which then transmits these vibrations to the inner ear. The inner ear contains tiny hair cells that are responsible for translating these vibrations into electrical signals that the brain can interpret as sound. The frequency of the sound determines where in the ear these vibrations are detected, and a high pitched beep is typically detected in the higher frequency range.

3. Can a high pitched beep cause damage to hearing?

Yes, prolonged exposure to loud high pitched sounds can lead to hearing damage. This is because the hair cells in the inner ear can become damaged or die off if they are exposed to loud sounds for an extended period. It is important to protect your ears from loud noises, such as high pitched beeps, to prevent hearing loss.

4. Why do some people find high pitched beeps more annoying than others?

Everyone has a different level of sensitivity to different frequencies of sound. Some people may find high pitched beeps more annoying because their ears are more sensitive to those frequencies. Additionally, personal preferences and experiences can also play a role in whether or not a sound is deemed annoying.

5. Can a high pitched beep be a sign of a medical issue?

In some cases, a high pitched beep in the ear can be a symptom of tinnitus, which is a condition that causes ringing or buzzing noises in the ear. However, if the beep is only heard externally and not in the ear, it is unlikely to be a sign of a medical issue. If you are concerned about a persistent high pitched beep, it is best to consult a doctor for a proper evaluation.

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