Ever listened to a track with headphones on and heard a sound that seems like it’s coming from behind you? This is achieved with binaural panning - a tool that allows you to emulate the origin of a sound in three dimensions.
To understand binaural panning, think about the structure of the human head. We hear in stereo – two ears (microphones) plugged into our brain. It doesn’t matter if we’re listening to a 9.1 surround sound system, it’s all being heard via this stereo line-in built into our heads. Incredibly, our brains can still determine the origin of sounds fairly accurately. This is a complicated process, but in simple terms our brains determine the origin of a noise by assessing the differences in the sound as it reaches each ear. This includes the time difference between it reaching your left and right ear, and frequency differences as your body blocks some frequencies from being as prominent on one side as the other. Our brains interpret all this data in an instant and tell us the origin. Pretty cool, huh? And because all sound is condensed down to our stereo ears, it’s theoretically possible to trick our ears and replicate any immersive sound experience via binaural panning.
The downside: before we go crazy and create a magical 3D song with instruments surrounding you, it should be noted that this panning method really only works ideally when heard with headphones. Further to that, playing a track that heavily utilises binaural panning through speakers is likely to sound very average as the effect doesn’t work correctly when each of your output channels is heard in both ears, so the levels will be out of whack. Thus, an approach to this technique with some level of forethought is required. One approach is to stick to standard L/R panning for the bulk of your track - the essential bits that you want heard perfectly every time, regardless of what system it’s played back on. Then utilise binaural panning for those extra bits that are likely to only be noticed by headphone listeners anyway - things like ambient textures, subtle percussion, delay trails etc. Those easter eggs can add up to a fantastic immersive experience for your listener.
Some DAWs like Logic Pro have binaural panning built-in; for others there are aftermarket plug-in options, one of which is the new free plug-in from Sennheiser called Ambeo Orbit - a professional but exceptionally user friendly introduction to binaural panning. It’s a great time to experiment with playing tricks on one of the many interesting abilities of our brain.