Dolby Atmos Horror Noise

In an earlier blog I discussed what Dolby Atmos is, and what it is all about. Over the past few weeks I have been exploring more of what Dolby Atmos can do. Here I will share with you a short experimental binaural soundscape I have created.

Dolby Atmos is based upon a 7.1.2 channel bed, with up to 118 additional audio objects which can be positioned within the space. My experimental piece utilizes two audio objects moving around the room. These objects are horror voice and sound effect samples. Each object will be sent to a reverb which will make up the 7.1.2 channel bed of room. The screenshots below show the Pro Tools session:

Screen Shot 2017-12-07 at 2.26.52 PMScreen Shot 2017-12-07 at 2.26.52 PM (2)

The top screenshot shows the Dolby Atmos Panner automation and the movements within the Dolby Atmos Monitor application. The bottom screenshot shows the mixer page with reverb settings, including positioning and divergence amount for each of the two audio objects within the room.

A really useful feature of working with  Dolby Atmos is the ability to easily monitor both binaurally and using the speaker configuration of the studio working from. It is easily configurable within the Dolby Atmos Renderer application. In this case I was monitoring the 7.1.2 in Virtual Reality (VR) mode over headphones, while being able to switch to the 5.1 surround speaker setup of the studio. I was very impressed with how everything sounded through the 5.1 speaker configuration.

If you would like to have a listen to my short piece, put on your headphones and click below.

Ambisonic Orchestra

On 24th and 25th November 2017 I had the great pleasure of recording Ramsbottom Choral Society and Orchestra during their final rehearsal, then concert performance of Handel’s Messiah. Having used surround microphone positioning (Rode NT4, Rode NT2-A, 2 x AKG C214) and the SoundField ST450 microphone, I decided to take a short piece from the recordings to create an ambisonic and binaural mix.

The surround microphone setup was recorded into a laptop running Avid Pro Tools, while the SoundField ST450 was recorded into a Zoom F4 field recorder. The recorded audio was to be synchronised later.


The Zoom F4 was ideal to capture the first order B-format W,X,Y and Z audio channels from the SoundField ST450. These B-format audio recordings were decoded using the free SoundField SurroundZone2 plugin within Reaper. This plugin can be used to decode any B-format audio, not restricted to audio recorded using SoundField products. Below is a screenshot of the decoded 5.1 positioning using the SoundField SurroundZone2 plugin.

SurroundZone 5.1

Having decoded the SoundField ST450 recordings to 5.1, I needed to position the other microphones recordings within the mix. I have been using the ambiX ambisonic plugin suite for a while and would like to demonstrate some of its’ uses. The ambiX suite uses convolution of head related transfer function (HRTF) databases and loudspeaker impulse responses (IR) to create ambisonic and 360 audio content. It is also possible to use the ambiX suite with HRTF databases or IR presets created by yourself. This is something I am exploring further, but I need to understand MatLab in more detail. If you are interested in creating your own databases the AES69-2015 standard is a good read.

Using the Binaural Decoder within the ambiX suite, I was able to simulate 12 virtual loudspeakers in a dodecahedron array. The screenshot below shows the pan positions of the five microphones used.


The AmbiX Encoder is a spherical panner. The Rode NT4 was positioned high above the conductor’s head when recording, so I have positioned it with left/right at -/+ 90 degrees azimuth with 60 degrees of elevation to give some stereo height within the mix. The Rode NT2-A mono mic was also high and behind the conductor, so is central with 75 degrees of elevation.  The pair of AKG C214 were stereo room mics and have been positioned accordingly within the mix.

I did experiment with using higher order ambisonics and more virtual loudspeakers (up to 50), however due to the natural room reverb within the open recordings, it causes phase issues during convolution with the impulse responses.

If you would like to listen to the audio, please click below (headphones required):

Avid Pro Tools S6 and Dolby Atmos

Last week I returned to The University of Salford to commence Semester 2 of the MSc Audio Production course I started in January 2017. After a long summer break I have been eagerly awaiting my return to the course.

As part of my studies over the next few weeks I will be using some new studios and equipment. The University of Salford has installed two new Avid Pro Tools S6 control surfaces into it’s studios at the MediaCityUK campus. Today a short introductory session was arranged with Bernie Steer, to demonstrate the operation of the Avid Pro Tools S6 and the workflows within the Dubbing Theatre.

The Avid Pro Tools S6 control surface is based upon a modular design, which enables it to be fully customizable to the user’s studio requirements. The recent Pro Tools HD 12.8 update, introduced support for Dolby Atmos mixing and audio rendering. The Avid Pro Tools S6 control surface should give deep integration with the software, for parameter control, manipulation and speed of mixing.  A promotional video by Avid,  demonstrating some of the new improvements with the Pro Tools HD 12.8 update with Dolby Atmos support is shown below:

Dolby Atmos is a form of three-dimensional audio, which is designed to give the listener a fully immersive experience. Conventional stereo and surround sound setups (such as 5.1) place the audio around the horizontal speaker positioning, Dolby Atmos uses height and objects to create an audio atmosphere. Audio objects can be placed anywhere around the listening position, to enhance the experience for the listener. Below is a video by Dolby explaining in detail the principles of how Dolby Atmos works:

During this semester of the MSc Audio Production I shall be undertaking some mixing in Dolby Atmos for video and audio projects. I will post further updates as I begin to use the Avid Pro Tools S6 for mixing the projects over the next few weeks.