Why do I hear a different tone of an ambulance sirene when it is coming to me/ going away from me?
355465
Doppler effect is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. URL: http://en.wikipedia.org/wiki/Doppler_effect
759343
thats abit wierd.... \n\nwhen you get a txt or your phone rings the speakers go dodgy.. but never heard of that... \n\nSure ur not haunted!!!
413598
blackpowder or gunpowder exploding makes the cracle sound. they just put it in smaller sections so it wont be as loud
246654
It is a lyricle ring tone that is meant to be an attention getter.\nYou might hear it upon causing some "event" to happen in Windows software. (as you probably already know)!
923187
Since sound travels faster than the speed of the train,there will be overlapping of sound as it approaches you (i.e Doppler effect) the pitch is high and highest when it crosses you..The closer you are to the track ,more will be the effect.As the train passes away from you the sound dies down in a drawn out fashion.
609158
someone will come along and answer this better than me! but i think its something to do with the fine hair things in our ears (forget what there called) they get bent down during loud nusic, they try to get back to normal and create this sound while trying to get back to normal.(am i making any sense here) my ears are ringing now as i have just come in from a club!
201175
well if you have dialup and that's when you hear it then it would be your modem connecting to the internet through the phone line, and the noises would be the electrical signals being changed into sound and then being sent through the phone line
180649
Broadband spectrum of non- regular pulses from 10 Hertz to\n200 KiloHertz in bursts of alternating frequency ranges\nof high/low,  to cover the entire human ear range of\nsounds, in a manner that is not consistent with other\nsounds, such as the regular pulse of CD/radio/MP3 speakers within a passenger vehicle playing music, and as diverse\na range so that people with a gap in one or more frequency ranges will pick up the other frequencies, and...\nirregular enough that the pulsing does not combine in a\nheterodyne-type of mixture with road tire noise, heater/airconditioning blower fan pulses, and composite road /drive train/wind noise to creat a harmonic blend that is dampened. Irregularity is a key to increase the awarness time. Alternating high/low frequencies means that the low frequencies travel well through the heavy frame members, and \nhigh frequencies travel thorough lighter areas of vehicle construction. Expensive automobiles have heavy ( weighted) padding glued to many interior car sections to cut out road noises - and it works. They also have lighter styrofoam and composite materials filling air pockets to dampen the low frequency road and drive train "throbs" comming from the engine compartment. I have had the radio on an alternative music station with synthesizers blasting unusual\nfrequencies, and much to my horror, glanced in my mirror to find an ambulance behind me trying to get my attention. It was not until I turned off the radio that I heard the pathetic BEE BAW of the siren. ... Locomotives use two or three different frequencies, which are quite LOW on the human audio scale, and these low frequencies can be heard MILES away. Transports, again use two or three lower frequency blasts from air horns, and again, the lower frequencies can vibarate right through most well insulated vehicles. The "standard" pathetic BEE BAW two tone regular patterned, weak siren common today is too narrow a region of the human range, too regular, too weak, and easily blocked by any expensive vehicle's sound insulation. Turning on any music can totally obliterate the noise.... Much better technology can be employed, ... and should be!\n How come I can hear some kids punked out stereo system BOOMing 2 city blocks away, as the car races towards me, and I can't hear an ambulance that is sitting on my back bumper?\nGo figure.
274177
The volume change is only a matter of distance from the horn to you.\n\n As a sound emitter approaches you, the frequency change, doppler effect, is caused by the shortening of the wave length as the back end of the wave is "compressed" against the front of the wave . Shortened wave length equates to higher frequency for approaching sounders. \n\nAs an emitter moves away from you, the back end of the wave is stretched out away from the front end of the wave, the wave length increases, and the frequency decreases.
399636
sounds like an anxiety/panic attack
790288
This is due to the Doppler effect. You know how when a car is coming towards you it has a higher pitch sound, and when it is driving away from you it has a lower pitch sound? This is called the Doppler effect, and it basically works like this:\nSound (and light) are waves that are emitted by the source (in this case the car, and as the source travels towards or away from you, these waves bunch up (towards) or spread out (away). This bunching / spreading causes the waves to interact with eachother. Basically, if the source is moving away the wave's frequency decreases (so the sound is lower) and as the source moves towards you, the frequency increases (so the sound is higher). It works the same with light (red for lower frequencies, blue for higher frequencies).\nSo, does this mean that all the stars out there are moving? Hell yeah! And they're moving pretty fast, too! The vast majority are moving away (so most are red-shifted), bt a few are racing towards us, so they are blue-shifted. The light from the big bang that created the universe itself is moving away from us so quickly, it has shifted past red and all the way to the microwave spectrum (yup, that stuff you use to reheat your morning coffee), and appears as background radiation.\nHope this helps.
249913
It may be possible that your phone line is not working well \ncheck your telephone if its producing strange sounds then you must contact your line-man and solve this problem.
1110838
Just leave your radio off.I'm sure they have a radio blarring somewhere.Smartass.
161386
Probably ultrasonic....
919461
Yeah it sounds haunted to me man get the hell out of there
353520
Dude, Sound travellin thru air is 'different' from the digital sound that goes thru ur phone!
771371
You just need to tell us everything is OK. \n\nHowever, if say, someone was screaming, and we called back and you say everything is ok--- you would still get the officers knocking on your door. (That happened last night, cuffed & stuffed, assault, family violence )\nWe listen to the background on all calls as well as your voice. \n\nIf not an emergency and we can't hear anything suspicious, we will cancel, but only then.