my ear phones working as a mic!

[ace.neerav]

or me this is like when all over india the idols of lord ganesha were drinking milk! its simple amazing. here is what happened.

my bro, surfing on the thoshiba laptop, came over to my room and asked me to accept the yahoo voice conv invitation. i said that i was on adium on my mac which doesnot supprt voice. i asked him what he was trying out. he said his friend told him that one can use a pair of ear phones as a mic simply by plugging it in the mic in port. i said "are u gone dumb! what kind of an electronics engineer are you". next thing i know i get an email which has a voice main over gmail from my bro. i can hear his voice! he calls me in his room and shows me how it works. now i know my toshiba doesnot have an inbuilt mic like my mac. but to be sure, i unplug the ear phone and try to do it again. it doesnot work. with the ear phones it does work! this were my ipod nano 2nd generation ear phones.

now, i plug the ear phones in the mic in jack of my mac. and from system preferance pane i see to it that Line in is selected and not in built mic. whoa! it does work.

but is it only with my apple ear phones? well no, even my aiwa ear phones work! i was wondering if those tine whole on the other side of the ear phone were working as a mic. but whatever it is, it makes no sense why someone would add mic to an ear phone. and from my knowledge of amplifiers, i know, its not possible for an out put device to record input whithout a sensor.

can anyone give me any insight?

 

[ariakovo]

or me this is like when all over india the idols of lord ganesha were drinking milk! its simple amazing. here is what happened.

my bro, surfing on the thoshiba laptop, came over to my room and asked me to accept the yahoo voice conv invitation. i said that i was on adium on my mac which doesnot supprt voice. i asked him what he was trying out. he said his friend told him that one can use a pair of ear phones as a mic simply by plugging it in the mic in port. i said "are u gone dumb! what kind of an electronics engineer are you". next thing i know i get an email which has a voice main over gmail from my bro. i can hear his voice! he calls me in his room and shows me how it works. now i know my toshiba doesnot have an inbuilt mic like my mac. but to be sure, i unplug the ear phone and try to do it again. it doesnot work. with the ear phones it does work! this were my ipod nano 2nd generation ear phones.

now, i plug the ear phones in the mic in jack of my mac. and from system preferance pane i see to it that Line in is selected and not in built mic. whoa! it does work.

but is it only with my apple ear phones? well no, even my aiwa ear phones work! i was wondering if those tine whole on the other side of the ear phone were working as a mic. but whatever it is, it makes no sense why someone would add mic to an ear phone. and from my knowledge of amplifiers, i know, its not possible for an out put device to record input whithout a sensor.

can anyone give me any insight?

I know that it works.I tried this 8 years before with a friend.I try to explain this now.The microphone is electrolitic so the capacitor that takes the waves (voice) on air and "translate" them in change of capacitance.So the line in lets a litle curent pass throug the capacitor and as the capacitor change the current change and this small change is you voice (pA if I remember well).About the head phones now.I think I am not sure of cource but if you put a head phone in the line in then a small curent will pass throgh the head phones because of the shape (they use a magnet and a material like plastic or paper) any change on the open air will affect the head phone (the material pulsed and the the current change) and of cource this small change will affect and the current pass through them so you can translate it again to voice.I think that this is a good explanation because it works and there must be an explanation.Sorry for your time I hope I help.

 

[Nigel Goodwin]

I don't like to 'rain on your parade', but this is so commonplace I doubt anyone would even mention it?.

Almost all audio transducers work both ways, with varying degrees of success.

My daughter (who isn't into electronics) has even used her MP3 player headphones as a microphone to record vocals at school, purely from her knowledge of music and music technology.

 

[Torben]

A speaker works as a microphone if hooked up as one. Try hooking up a speaker to the input of a preamp and shouting into it. A speaker works on the same principle as a microphone, just reversed.

Speakers perform much better when used as speakers than when used as microphones, though. And a microphone works better as a microphone since it was designed for the job.

So yes, it's perfectly possible. It's not usually a very good idea though.


Torben

[Edit: Nigel beat me to it.]

 

[rahulan999]

This would not seems to be a new idea bro, if you know the principle behind a mic and an earphone(speaker). Both are run by same principle and a speaker will 'resonate' when it is connected as a speaker and vice versa. You know most of the mics - ie dynamic, condensor,piezo will work as a speaker when connected to a audio source!

 

[Hero999]

Earphones are probably better than speakers because they have less resonance.

Old walkie talkies used the speaker as a microphone when in talk more. They hissed and crackled a lot because they used a regenerative receivers.

You can make a simple telephone by connecting a pair of speakers together with wire, if you talk into one, you'll hear your voice very faintly out of the other.

 

[3v0]

...You can make a simple telephone by connecting a pair of speakers together with wire, if you talk into one, you'll hear your voice very faintly out of the other.

A more techie version of 2 tin cans on a string.

 

[radiomate]

Andre Marie Ampere of France noticed that a wire carrying a changing current will move in a magnetic field, Michael Faraday of England noticed that a wire moving in a magnetic field will generate a current... Bedi bedi bedi that's all folks

 

[valve]

This person will fall down with excitements when he connects his dc dynamo into a powersupply

 

[radiomate]

Depends if the power supply is AC or DC

 

[radiomate]

Hey Nigel, how come members with fewer posts than me have reputation=good, while my reputation=newbie?

 

[Nigel Goodwin]

Hey Nigel, how come members with fewer posts than me have reputation=good, while my reputation=newbie?

Reputation is set by how people vote for you - they can give you positive rep or negative rep.

 

[radiomate]

Hmmmm so that's how it works... we live and we learn

 

[jasonbe]

Why is it that when I go to http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=720968;keywords=microphone and http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=720966;keywords=speaker I find that microphones are rated in terms of volts and speakers are rated in terms of watts? What would be the best way to compare both of these devices, by dB levels? I’m actually interested in making a microphone port connection (not a microphone) compatible with a speaker port connection (not a microphone), and would like to hear any ideas that people have about how to do this.

 

[abg]

Yes it has to work. If not can't be an electronic gadget. Enjoy it. One more Idea.....connect a simple diode to it and put it in your "ear hole" ...it receives local Radio station signal.. multyply the usage.

 

[ormo]

It's possible because almost all audio transducers work both ways. You'll probably get a better sound with a real mic though

 

[audioguru]

A speaker is rated by it max power handling in Watts. Its sensitivity determines its dB level at its max power rating. Most speakers also have a dB rating when the input is 1W and the dB level is 1m away. Most speakers are 86dB to 92dB at 1W, 1m.
Tiny little speakers have much less sensitivity.

 

[Hero999]

They also give a test frequency of 1kHz.

 

[jasonbe]

Can you compare the energy involved in microphone and speaker usage in common units other than decibels? About what would an actual measurement be in these common units for the types of microphones and speakers used in portable compact tape recorders?

 

[audioguru]

Tape recorders have not been used for at least 15 years.
The output from an electret mic at a distance of about 15cm and you talk with normal volume is 10mV.
Speaker output levels are on their datasheet.