Best way to record a spatial experience

Question

I'd like to record a single voice 'in front' of me. I'd like for it to move left and right but still give the impression of being in front. Whenever I try it, it the voice feels inside my head, moving from right to left side, but still within my head.

Most tutorials I've read head into YouTube VR territory which isn't what I want. I don't care about tracking. I just want the ability for things to sound like they are around me in various locations.

I've read about ear shaped microphones (like 3Dio) and I can certainly do that but I was hoping to at least approximate the effect by recording 4 channel (with my Zoom H2N) and mixing it down. Does anyone know a) if that's reasonable and b) if there is a tutorial on how best to attempt this?

I hope it's clear I appreciate that the 3Dio microphones are probably the best solution. I just wanted to know if there was a way to use my existing equipment, even if it doesn't give as strong an experience.

Answer 1

Another great free tool for HRTF-based binaural encoding is the Ambisonic Toolkit: http://www.ambisonictoolkit.net/ This is a B-format encoder/decoder: when you suggested recording 4 channels and then converting to binaural, the technology to do so is ambisonics, using a 4-channel encoding called B-format. However, I'm not sure how easy it is to manually record 4 channels and get them to translate properly to B-format. There are mics that do that. It -might- be relatively simple, but I've heard that even with the specially made soundfield mic you can run into all sorts of phase issues.

BUT: Ambisonic Toolkit will also encode a mono source, let you pan it around in 3D space, then decode to binaural.

When you install it and realise how many separate plugin components it consists of it might seem intimidating, but the documentation includes some very helpful videos that explain the workflow. You'll realise that for binaurally spatialising mono sound sources you just need a set configuration of at least 3 plugins - and you can save this as a template session in Reaper. I've used exactly this setup to do just what you're proposing - making a voice pan left to right (AND up and down and behind) in a way that puts it 'outside your own head' on headphones.

The one thing you'll notice is lacking or mismatched when working in this way is the reverb. This is especially so if your source recording is not completely dry, and its roominess/reverb is carried with it as a constant no matter where it's panned. To some extent that breaks the illusion, but it's still very good - as long as your recordings are clean.

Of course the most complete binaural image, including reverb/room response, comes from recording binaurally. But besides 3Dio/dummy head microphones you can easily do the same thing by sticking small (lav-style) omni mics directly into your own ears. I've done this with DPAs with great results.

Answer 2

It seems achievable using mono files and doing extra-careful,senstive mixing.

If you're also interested in useful VR tools, the spatializer Occulus included in their development kit is quite useful at setting sound at a specific point in space. You can use it standalone, in daw, middleware, in game engines - it's pretty awesome:

https://developer.oculus.com/downloads/audio/

Answer 3

I am assuming you are auditioning the content on headphones - going by your experience of the sound of the voice being "inside" your head.

There are a couple of ways to achieve bringing the voice forward into the front of the sound-stage.

1. you use spatial audio techniques with ambisonic encoding and binaural decoding with a specific Head-Related-Transfer-Function (HRTF).
2. a simpler way might be to mix in some delay to each of the Left and Right channels. Normally stereo works like this - A->L B->R. To achieve what I am outlining you do this.... A+(B')->L B+(A')->R . A' is A with a small amount of delay (i.e. 15-20ms) - same with B. You can vary the delay to achieve movement of the sound source in the sound-stage.