# Fire alarms - why high-pitched noise? **URL:** \ **Category:** Factual Questions\ **Created:** [January 16, 2008, 11:24am UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725 "2008-01-16T11:24:38Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [January 16, 2008, 11:24am UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/1 "2008-01-16T11:24:38Z")
My father was complaining about not being able to hear high-pitched smoke alarms due to partial deafness, so I had a look on the [RNID factsheet](http://www.rnid.org.uk/information_resources/factsheets/equipment/factsheets_leaflets/?ciid=304996) with a view to finding alternatives and it says > [@RNID / BS5446-3](#): > > a self-contained smoke alarm that makes a high-pitched noise when it detects smoke But why high-pitched? Wouldn’t something that emitted a loud low-pitch noise be just as effective? ---
**Author:** ![Jean\_Gray](https://avatars.discourse-cdn.com/v4/letter/j/7feea3/32.png) [@Jean\_Gray](https://boards.straightdope.com/u/Jean_Gray)\ **Post date:** [January 16, 2008, 1:03pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/2 "2008-01-16T13:03:43Z")
Speaking as a normal-hearing person, loud low-pitched sounds (like, say, the bass line at a stadium concert in which you happen to be standing right in front of the speaker) grab your attention, but in a bone-thrumming kind of way that’s not that unpleasant. If I were asleep when the sound started - and I’m a heavy sleeper - I doubt I’d notice unless the bed were also shaking. A high-pitched sound is absolutely painful on the ears though - have you never experienced a fire alarm up close? There’s a reason that “piercing screams” are invariably referred to as high-pitched! ---
**Author:** ![groman](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@groman](https://boards.straightdope.com/u/groman)\ **Post date:** [January 16, 2008, 4:51pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/3 "2008-01-16T16:51:17Z")
[QUOTE=Jean Gray] A high-pitched sound is absolutely painful on the ears though - have you never experienced a fire alarm up close? There’s a reason that “piercing screams” are invariably referred to as high-pitched! [/QUOTE] A lot of fire alarms I’ve heard at schools and companies were intolerable for me. As in outright disorienting vomit inducing audio-horror. I don’t know who came up with one particular “screech-hiss-screech-whine” pattern combined with off-beat strobe lights but it felt like the 9th circle of techno hell. I’d love to know there is some justification for it other than being an effective emetic. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [January 16, 2008, 5:05pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/4 "2008-01-16T17:05:20Z")
[QUOTE=groman] \ I’d love to know there is some justification for it other than being an effective emetic. [/QUOTE] It made you want to leave the room. Mission accomplished. ETA: They’re not _supposed_ to be tolerable. ---
**Author:** ![Solfy](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@Solfy](https://boards.straightdope.com/u/Solfy)\ **Post date:** [January 16, 2008, 6:06pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/5 "2008-01-16T18:06:19Z")
Lower pitches are omnidirectional. It is easier to determine the origin of a high pitched noise, which makes it easier to realise that the noise is coming from up on the ceiling where the smoke detector is. ---
**Author:** ![UltraVires](https://avatars.discourse-cdn.com/v4/letter/u/ecccb3/32.png) [@UltraVires](https://boards.straightdope.com/u/UltraVires)\ **Post date:** [January 16, 2008, 6:16pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/6 "2008-01-16T18:16:05Z")
[QUOTE=Santo Rugger] It made you want to leave the room. Mission accomplished. ETA: They’re not _supposed_ to be tolerable. [/QUOTE] Yes, but the problem is, I would guess that I have heard over a thousand smoke/fire alarms in my life and the number of those alarms that represented a real fire? Zero. People have become so accustomed to the false alarms that they will sit through a real one until it’s too late, all the while bitching about the noise.. ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [January 16, 2008, 7:39pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/7 "2008-01-16T19:39:14Z")
Being hearing-impaired, I cannot hear the super-high pitched smoke alarms unless I am in their immediate vicinity. This causes no end of consternation from my wife while I am cooking 😃 I would love a smoke alarm that emitted lower frequency noise. It doesn’t have to be a deep relaxing bass, just not super high pitched. Something along the lines of a low altitude cockpit alarm in aircraft. Those are loud, and DEFINITELY get your attention without sounding like a piezo-electric buzzer on steroids. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [January 17, 2008, 3:22pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/8 "2008-01-17T15:22:24Z")
Things like ships’ klaxons are lower-frequency and they seem to grab attention just fine. ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [January 17, 2008, 3:35pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/9 "2008-01-17T15:35:59Z")
[QUOTE=Quartz] Things like ships’ klaxons are lower-frequency and they seem to grab attention just fine. [/QUOTE] EXACTLY! If I could get a smoke/CO alarm that sounded like a ship’s klaxon I would be a happy camper. The coolness factor would be a plus. ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [January 17, 2008, 6:35pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/10 "2008-01-17T18:35:34Z")
[QUOTE=jtgain] People have become so accustomed to the false alarms that they will sit through a real one until it’s too late, all the while bitching about the noise.. [/QUOTE] Hence the arms race to make them less and less tolerable. Mark my words, in twenty years, fire alarms will have to shoot out _actual jets of fire_ before people will leave when they start. ---
**Author:** ![BellRungBookShut-CandleSnuffed](https://avatars.discourse-cdn.com/v4/letter/b/bcef8e/32.png) [@BellRungBookShut-CandleSnuffed](https://boards.straightdope.com/u/BellRungBookShut-CandleSnuffed)\ **Post date:** [January 17, 2008, 9:38pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/11 "2008-01-17T21:38:32Z")
Dunno how widespread they are, but at college they had the ones that not only had a high-pitched bell (BRRIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIING), but also a low-to-middling pitched buzzer (BRAAAAAAAAAAAAAAAAAAAAAAAAAAW). Maybe they’re covering all of their bases? and thus ends my first attempt to find onomatopeoias which transcribe pitch ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [January 17, 2008, 9:43pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/12 "2008-01-17T21:43:28Z")
[QUOTE=jtgain] Yes, but the problem is, I would guess that I have heard over a thousand smoke/fire alarms in my life and the number of those alarms that represented a real fire? Zero. People have become so accustomed to the false alarms that they will sit through a real one until it’s too late, all the while bitching about the noise.. [/QUOTE] I don’t understand where you’re coming from? Are you saying fire alarms should just have a small LED, and no noise, so they’re easier to sit through? ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [January 17, 2008, 11:31pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/13 "2008-01-17T23:31:01Z")
As many of you have noted, there was no standard for many years. Bells, sirens, buzzers, and more could be used as audible fire alarm notifying signals. From the National Fire Alarm Code, NFPA 72, 1999 edition: > [@](#): > > A-3-8.4.1.2 Paragraph 1-5.4.7 requires that fire alarm signals be distinctive in sound from other signals and that this sound not be used for any other purpose. The use of the distinctive three-pulse temporal pattern fire alarm evacuation signal required by 3-8.4.1.2.2 became effective July 1, 1996 for new systems installed after that date. It had been previously recommended for this purpose by this code since 1979. It has since been adopted as both an American National Standard (ANSI S3.41, _Audible Emergency Evacuation Signal_) and as an International Standard (ISO 8201, _Audible Emergency Evacuation Signal_). The NFPA and other organizations continue to study the problem of emergency notification via audible means and their effectiveness on children, the elderly, and the hearing imparied, as well as the general public. ---
**Author:** ![SharkB8](https://avatars.discourse-cdn.com/v4/letter/s/977dab/32.png) [@SharkB8](https://boards.straightdope.com/u/SharkB8)\ **Post date:** [January 17, 2008, 11:34pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/14 "2008-01-17T23:34:48Z")
We had a fire in the lower level of my house in 2003 and I SLEPT through the fire alarm, which was on the ceiling in the hallway right outside of my open door…maybe they should all play “Reveille.” ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [January 17, 2008, 11:42pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/15 "2008-01-17T23:42:47Z")
The drivers (speakers) for higher frequencies are both smaller and more efficient. Both of these characteristics are desireable from a design and manufacturing POV. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [January 17, 2008, 11:57pm UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/16 "2008-01-17T23:57:10Z")
[QUOTE=Cervaise] Mark my words, in twenty years, fire alarms will have to shoot out _actual jets of fire_ before people will leave when they start. [/QUOTE] To paraphrase Irish comedian Tommy Tiernan: You could be sitting in a pub made of Christmas trees and petrol, in between a fireworks factory and a home for young criminals, and if the fire alarm went off, people would be sitting around making jokes about it: “Hahahaha. Is that my phone?!” ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [January 18, 2008, 12:13am UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/17 "2008-01-18T00:13:26Z")
[QUOTE=jnglmassiv] The drivers (speakers) for higher frequencies are both smaller and more efficient. Both of these characteristics are desireable from a design and manufacturing POV. [/QUOTE] But they’re not desireable in this case! ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [January 18, 2008, 7:12am UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/18 "2008-01-18T07:12:13Z")
[QUOTE=Dorjän] Being hearing-impaired, I cannot hear the super-high pitched smoke alarms unless I am in their immediate vicinity. [/QUOTE] They make fire alarms which include a bright strobe flash as well as a audio alarm, specifically for the hearing-impaired. I imagine there are similar smoke alarms available, if you want one. ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [January 18, 2008, 7:15am UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/19 "2008-01-18T07:15:05Z")
[QUOTE=t-bonham@scc.net] They make fire alarms which include a bright strobe flash as well as a audio alarm, specifically for the hearing-impaired. I imagine there are similar smoke alarms available, if you want one. [/QUOTE] They do, but if the smoke alarm is in the hallway, and I’m asleep in my bedroom, a strobe light won’t do much good. ---
**Author:** ![Jeff\_Lichtman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jeff_lichtman/32/1531_2.png) [@Jeff\_Lichtman](https://boards.straightdope.com/u/Jeff_Lichtman)\ **Post date:** [January 18, 2008, 8:30am UTC](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725/20 "2008-01-18T08:30:03Z")
It takes a big speaker and a lot of energy to produce a loud, low-pitched sound. Smoke alarms are small and most of them are powered by small batteries. I suppose it would be possible to make an alarm with a ten-inch woofer that would run off of household current, but most people wouldn’t want one like this. [Next page](https://boards.straightdope.com/t/fire-alarms-why-high-pitched-noise/433725.md?page=2)