Binaural Stereo Recording

Posted by glen609 on May 2, 2009

Please don’t talk to me, I’ve got microphones in my ears.

What?

It makes perfect sense, grasshopper. If you want to capture in an audio recording exactly what you hear, then you need to put the microphones in your ears. But why?

Have you ever wondered how it is that you can discern whether a sound is in front of you or behind? You only have two ears so something is going on. Two evenly spaced microphones can only distinguish Right and Left because two points makes a line and that’s the definition of One Dimensional. Right and Left, for example. But stick those microphones in your ears and the magic happens.

I use these mics from Soundprofessionals.com. They’re great powered by one of their battery modules and a High MD minidisc recorder, going into the line in jack for loud shows. Perfection.

It turns out that the shape of  your head and ears, pinnae in the parlance, play a not so surprising and important role in what your brain hears coming from your ears. There are very subtle temporal and phase shifts from the incoming sounds that your brain deciphers and translates  into a fully Three Dimensional soundscape. That means you can tell that that annoying girl on her cellphone is actually behind you, or in front of you, or above you, if you’re lucky, below you.

And you can capitalize on those facts by sticking the microphones into your ears and playing back the resulting recording on headphones, making sure you have them on the right way or your poor brain might get things backwards, might think the band is actually behind you. It’s wierd, I know, but true.

Now, it’s unfortunate that the best listening experience comes from the person that did the recording because she has the identical pinnae and other’s heads might get confused, but there’s nothing I can do about you stupid pinnae. The recordings are still nice. Enjoy.

Wiki on this subject for more.