Creating Realistic Binaural Acoustics

[amka]

Hello,

Two and a half years ago, I started making music; I find it a very interesting and vast subject. I would like to deepen my work and, in that regard, I was impressed a few months ago by a song I heard on the radio.

I honestly thought a sound (from the radio) was not coming from my headphones - I believed something producing that sound was actually in my room.

I would love to be able to create such a sound. I am currently working with Ardour (DAW) on Debian Linux (OS); I have started using Panagement2 (binaural plugin) and IEM (Ambisonic plugin).

Could someone please help me move forward with this task?


Thanks!

Amer

[Pan Athen]

I love that topic because it's a complicated one, and you know what's the great thing about complicated topics? It doesn't matter if you achieve 100% of what you're going for or not, you're still gonna learn a lot about it.

Now, let's say you want to achieve the same sound as if the source is coming from your living room while listening to headphones, right?

A simple answer would be that you should try to emulate some of the characteristic of a sound that passes through the same changes as a sounds that really came from your living room would. You could for instance get a dry sound like a short burst of wideband noise and play it through a speaker placed in the room exactly where the source should be, and then put a microphone at the position of the listener and record that short burst coming from the speaker. You can then analyze the recorded file, and if you have the ability to also reverse engineer any changes that the speaker and the recording chain added to the final file. This is not easy but can you see where I'm leading you? You need to know what changes happen to the sound while travels from it's point of origin to your ears.

Here's a list of what changes as sound energy is transferred from the point of origin to your ears:

1. It loses high frequencies because of the friction between the air particles, the phenomenon is called damping. Temperature and humidity also play a role here.
2. It gets multiplied by all the reflections that are created by the sound interacting with the surfaces around the space. Those are separated into Early Reflections which are the first sparse reflections that our brains use to define spatial information, and Late Reflections which are the diffused multiple reflections that arrive later and our brains use to define the space's size and other things. The characteristics of both the early and late reflections also define the room.
3. Two ears actually get two copies of the sound, the main differences between them is the difference in time (because of the ear-to-ear distance) and the difference in frequency spectrum (because of the acoustic shadow that our head produces for each ear). Those differences define a lot of the information at our brains for where a sound is coming from. This is what binaural plugins usually do.

So as you see the effect you try to achieve is not only done by binaural panners but also needs careful set up of a reverb plugin and filters to simulate air damping by distance.

To add to the complexity of that, think that even if you do all that, the final sound will still emulate your living room and not another person's living room.

But you can simulate a more generic living room and achieve a high percentage of realism so that the end result will be believable in most living rooms from listeners with headphones.

More realism can be achieved my augmented reality technologies but that's out of the scope of this discussion, unless you want to also develop a specialized app that delivers your music in this unique but very believable way.

Thoughts?

[amka]

Thank you for your messages, Pan, and please excuse the delay in my reply.

It's true, "the journey is as important as arriving at the destination"; I've noticed this several times, and this mindset makes any study far more rewarding. I’m truly passionate about our subject, and things are becoming increasingly clear — thanks in large part to your help.

Your information is more than interesting. For example, the two types of reflections, damping and the sound shadow of the head, have allowed me to understand the phenomenon.

I’ve started some experiments following your advice, and I’ll be happy to share them in this part of your forum.

Sincerely, and see you soon!

[Pan Athen]

Sounds good, I'm looking forward to hear your experiments.

Btw, I changed the title of the topic to be a little more representative, for those who seek the same knowledge, I hope you don't mind