Issue link: http://digital.copcomm.com/i/1152266
Here are a couple of questions I was looking to answer when researching Aural ID. What do you need to do on your end? What do they do with what you give them? What do you get? And what do you do with it? Here's a look into my experience. CAPTURING I In order to create an accurate HRTF, one would, traditionally, have to put special microphones in their ear canals (not dissimilar to how the Realiser captures this) and record test signals in an anechoic chamber to remove the effects a room has on direct sound. The subject would have to be extremely still during the process so the orientation is consistent. Given the unlikelihood of people actually doing this, Genelec created a very clever approach for capturing this information using readily available technology. The technology needed is a video camera and a person to operate the camera. For me, it was my iPhone and my teenage son Michael. If you want to illicit a strange reaction, tell your kid, "Hey (insert said kid's name), I need you to video my head and pay particular attention to my ears." While not the cinematography debut he was looking for, Michael recorded my head by walking slowly around me as I sat on a stool in our garage (see photos on the next page). Genelec provides a good video example of how to do this with enough detail for the video to be effective. It's very easy to record this too quickly. Slow and steady are your friends, though you may have to introduce the concept to your kid. You then put a ruler up to your ear and take a picture to show its length and to provide a measurement reference for the folks at Genelec (again, insert odd reaction from kid). The video and the ruler photos of your ear are then uploaded to Genelec's site. PROCESSING I Back in Finland, Genelec's team uses software to create a 3D model of the head recorded in the video and seen in the photos. Once this is created, they use an acoustical simulation to calculate the acoustical field. The process measures the equivalent of 836 different orientations. Think about that for a second: 836. This allows for hundreds of aural origination points (e.g., monitors) to be represented in the HRTF. DELIVERY I Once Genelec has completed their processing, you are sent .SOFA files at three different sampling frequencies: 44.1 kHz, 48 kHz, and 96 kHz. The file to be used is based on your session's sampling rate. If you're unfamiliar with the .SOFA format, it stands for "Spatially Oriented Format for Acoustics" and is a format standardized by the AES to store acoustical data such as HRTF and binaural or directional room impulse responses. You can read more about the file at www .SOFAconventions.org. With Aural ID, this file contains your HRTF. INCORPORATION I Once I received the file, I was curious to hear what it would do. To use the file, you need a plugin or program that can read a .SOFA file. Pro Tools does www.WBSound.com ©2019 Warner Bros. Entertainment Inc. SOUND FROM PRODUCTION THROUGH POST.