Using analog sound equipment, backwards!

[WiscoMetro]

So today I accidentally plugged a wired unamplified microphone into my laptops headphone jack while I had music playing and noticed the music began to emanate from the microphone !

 

It didn't damage it it appears, though I'd still be reluctant to try this on purpose with anything expensive.

 

Then I tried doing the reverse and tried plugging my earbuds(Stereo TRR) into the microphone port and lo and behold I was able to hear my voice recorded by the left earbud.

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While I'm sure this effect is known and this might not be surprising to some people, it was entirely unexpected to me. Mind blown, and gave me quite the burst of wonder this afternoon!

[Alex Atkin UK]

1 hour ago, WiscoMetro said:

So today I accidentally plugged a wired unamplified microphone into my laptops headphone jack while I had music playing and noticed the music began to emanate from the microphone !

 

It didn't damage it it appears, though I'd still be reluctant to try this on purpose with anything expensive.

 

Then I tried doing the reverse and tried plugging my earbuds(Stereo TRR) into the microphone port and lo and behold I was able to hear my voice recorded by the left earbud.

 

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While I'm sure this effect is known and this might not be surprising to some people, it was entirely unexpected to me. Mind blown, and gave me quite the burst of wonder this afternoon!

You're right, its completed expected as functionally there is no difference between a speaker and a microphone - same way there is no difference between a motor and a dynamo/generator. 

 

The only difference is the amount of voltage you are dealing with so yes it will damage the microphone, hopefully not enough to notice from your short accidental experiment.

 

A microphone is designed to be super sensitive to generate tiny amounts of power from faint vibrations, whereas a speaker is designed to use power to create orders of magnitude more powerful vibrations.  The smaller the speaker, the less power/vibrations are needed, so headphones are closer to a microphone than a desktop speaker.

[Heats with Nvidia]

5 hours ago, Alex Atkin UK said:

You're right, its completed expected as functionally there is no difference between a speaker and a microphone - same way there is no difference between a motor and a dynamo/generator. 

 

The only difference is the amount of voltage you are dealing with so yes it will damage the microphone, hopefully not enough to notice from your short accidental experiment.

 

A microphone is designed to be super sensitive to generate tiny amounts of power from faint vibrations, whereas a speaker is designed to use power to create orders of magnitude more powerful vibrations.  The smaller the speaker, the less power/vibrations are needed, so headphones are closer to a microphone than a desktop speaker.

This is correct when you have a dynamic microphone, but please don`t try this with any other kind of microphone. With some it might work, bur many have electronics inside that might not like that trick.

 

But using headphones as microphones is always safe. That is a trick some DJs use when they have no microphone. The sound quality usually is not that great, but it works. By the way, if you have a loudspeaker chassis that you can directly contact to, using it as a pretty bad microphone will also work. But with two or three way speakers it doesn`t work very well, because the crossover is in the way.

[cooky560]

Most analog solutions work both ways, ie playback is the opposite of recording. Vinyl and tape work the same way btw. Technology connections did an excellent youtube video on this.

 

Provided that the voltage level is within what the hardware can tolerate, you will not damage your stuff using it backwards. The most common reason to do this is to turn headphones into a MIC in a pinch.

 

I should comment here that while vinyl also works both ways, to try and record vinyl without dedicated equipment will cause a lot of damage, and probably not work at all. The reason for this is that recording needles are designed to cut the vinyl, and so are configured very differently.

[Alex Atkin UK]

Indeed, analog audio after all is about replicating vibrations either electrically or mechanically.

 

I mean technically so is digital audio obviously, just with math tricks.

 

Then what really blows your mind is when you realise that light and radio waves are all part of the same electromagnetic spectrum, plus how and why it can be relatively easy to convert vibrations into EM waves and back again.

 

The key to all our technology has been figuring out how to record waves accurately and then play them back as accurately as possible.

[GoldenSound]

There's not much difference between a speaker/headphone transducer and a microphone at a basic level.

For a speaker/headphone an electric current applied to the coil causes a corresponding movement, pushing air and creating sound.

For a microphone, the air moves the transducer, and that causes the motion of the coil to induce a current that can be recorded.

 

The only type of transducer that can't be used as a microphone is an AMT (air motion transformer). Besides that, normal dynamic driver, planar magnetic driver, and electrostatic transducers can all technically be used in either scenario.

[Heats with Nvidia]

6 hours ago, GoldenSound said:

The only type of transducer that can't be used as a microphone is an AMT (air motion transformer). Besides that, normal dynamic driver, planar magnetic driver, and electrostatic transducers can all technically be used in either scenario.

They can be, but since most of the non-dynamic microphones have electronics inside. They won`t work if you try this without ripping out or replacing their electronics with something built for their new purpose.