How does stereo sound get recorded in a phone?

Divit Dsouza March 22, 2012
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I just found out that some phones are capable of recording stereo sound (with video).

How does it record? Doesn’t it need multiple mics?

Would be nice if someone explained the process of recording stereo sound.

  1. Silverdragon
    March 24, 2012 at 1:22 am

    Hi well you are quite correct in saying that there is only ONE mic, and subsequently how does it record and playback Stereo.. well to put it simply it can't and it doesn't however what it does do is in software it can manipulate the data stream and effectively recode it into two data streams, the signal can be frequency interpolated  and mixed these are then fed to the stereo amplifier and hey presto stereo.. but NOT true stereo as say from an FM radio, or an old fashioned stereo audio tape.. however our ears are unable to differentiate anyway. So it is sort of pseudo-stereo all done with software filters etc... in reality we could compare it to surround sound, which takes one stereo input and puts it out to 5 speakers. This is why if you listen to an old fashioned dual microphone and analogue filter recording and playback, there is far more tone, timbre and depth, of the sounds that just isn't there in these "modern" devices, however when one has nothing to compare to, no-one knows any different see...

  2. Achraf52
    March 24, 2012 at 1:15 am

    First, true stereo need 2 microphones and 2 speakers, then phone are an electronic device that handle sound very precisely so it would switch between two channels in recording at high speed the bring those together in software to make them look like stereo, but because the switch duration is very high it is impossible for Human to notice the difference .

  3. Tom
    March 23, 2012 at 3:05 pm

    I'd love to see a link to one of those phones, but you're correct - If it's "true stereo," it would need two mics. On the other hand, if it's simulated stereo, the effect can be "faked" through delays.