Creating a Binaural Headset

The theory behind making a binaural microphone system is pretty straight forward. Geeks might argue over which is the best set, the £6000 one or the latest in ear gear. If binaural is going to be listened to over the internet using some average head or earphones, then I imagine that the following plan would work well enough.

The idea of doing this came when looking at the Whatsapp conversation in the ‘fineartdigital’ group. Friederike has posted some binaural pop tracks which were so effective that it really did sound as thought the music were coming from outside the head and not in the ear.

The effect is not only due to the proximity of the sound being recorded nearer one microphone than its stereo other. This panning alone can be done in a sound editor, but it results in a rather flat movement from one side to the other.

The art of creating a spatial effect is somewhat more complicated than simply panning. For it to be as true to life as possible, the gain (or volume) of the sound does not alter all that much as in panning. I noticed as much in the Friederike’s music track. This made me think as to what else could be causing this effect.

If one ear is closer to the source of the sound than the other, and there is little or no connection between the two ears on account of a dense head being between the two, then the only other reason for the spatial effect must be the time it takes for the sound to reach either ear.

The nearest ear to the source will receive the sound a fraction of a second before the other ear. Perhaps as little as 1 millisecond. This delay then creates the sense of space as the brain triangulates the location of the source with respect to the head. And as the source moves further away from the microphones, the gain also diminishes and gives the sensation of being placed further away, or further outside the head.

How clear this effect is probably depends not only on the arrangement of the microphones but also their quality. But as I mentioned above, I think a pair of average lavelier microphones would do.

All this could be achieved in an editor or digital audio workstation or DAW. However, the amount of work in graduating not only the panning but the delay would make this a very complex task. Perhaps there is some software out there that can achieve the same thing but I suspect that most if not all such recordings are produced using a binaural setup rather than in postproduction. Post production could be used, however, to enhance the effect.

One of two microphones ordered today – chosen for its dynamic range for its class in relation to price.

I could build a binaural recording setup with two lavelier microphones, the Zoom H5 recorder as a preamp and some other bits and bobs. These would include: a dense material with which to simulate the width and mass of the head to isolate one mic from the other. The mics would have to be placed one head width apart. And I could fashion something resembling ears to act as actual ears and simulate the directionality of the listening organ.

I know of set ups which use a polystyrene head. I think there are better materials that can be used. Polystyrene is nowhere near as dense as a head and beside, the whole thing become unwieldy and silly looking. There is a set that can be bought which consists of a rectangular material one head width apart with very large, what appear to be, silicon ears. It is very expensive so I imagine that what maters is the distance apart and the density of the intervening mass to create the right amount of isolation.

The microphones have to be mono, which laveliers usual are and most importantly omnidirectional. Apparently electrotet mics are the ones to use. These are small so they need a preamp hence the Zoom. I could buy the mic capsules, but this would involve me in having to rig circuits with resitors and jackets and what have you. It really is not worth the trouble: it would only save a few pence and I would end up spending valuable time building the mics from scratch.

I could experiment with the ear configurations and make say, jackal’s ears – what the divine Anubis heard in the tomb!