To enable you to dive into Ambisonics, we’ve created a quick overview of the main features of dearVR AMBI MICRO. In this article, we want to show you how to listen to Ambisonics in your DAW using regular headphones, adjust an Ambisonics recording, and encode microphone signals coming from an Ambisonics microphone.
1. Listen to Ambisonics in your DAW using regular headphones
First, we have to prepare the DAW project. Because our goal is to listen to an Ambisonics-encoded audio stream, we have to create an Ambisonics output bus in our DAW. Depending on the selected DAW, we can choose between a first-order, a second-order, and a third-order Ambisonics format. The first-order Ambisonics (FOA) is in a 4-channel format, while the second-order Ambisonics (SOA) consists of 9-channels and, last but not least, the third-order Ambisonics (TOA) has 16-channels. The higher the order of the Ambisonics format is, the better the perceived immersive resolution will be.
If you want more information about setting up an Ambisonics project in Pro Tools, Nuendo, or Logic Pro, you can find detailed information in our dearVR AMBI MICRO manual.
To listen to the Ambisonics signal on headphones, we first have to insert dearVR AMBI MICRO into our Ambisonics output bus. This allows us to monitor Ambisonics signals using regular headphones and to render Ambisonics tracks right out of the box (supporting Ambisonics B-format inputs up to 16-channels TOA). Now, we want to listen to a first-order Ambisonics stream. To do this, we have to select the desired input format in the input section.
dearVR AMBI MICRO serves as an Ambisonics-to-binaural decoder. In the output section, dearVR AMBI MICRO lets us choose between the dearVR HRTF, the YouTube VR, the Facebook360 or the Neumann KU100 binaural rendering engines. Using this functionality we can immediately check our mix using the different final Facebook and YouTube format decoder.
To keep the scenario simple, we will simulate the possibilities to edit Ambisonics streams using the instance of the dearVR AMBI MICRO plugin, which we already inserted in our main output.
We can achieve a three-dimensional rotation of the sound field using the Yaw, Pitch, and Roll knobs. Yaw rotates the horizontal direction of the signal. Pitch can be used to correct the vertical orientation of the signal as well as enabling up and down movements. Roll adjusts the vertical orientation of the signal, enabling left or right changes.
3. Encode an Ambisonics microphone
The easiest way to dive into Ambisonics is to use an Ambisonics microphone like the Sennheiser AMBEO VR Mic. This mic has four matching capsules, thus enabling us to capture the 360 degrees surrounding sound from one single point. To record signals coming from the four capsules, we need a 4-channel field recorder or an interface with four gain-matched, phantom-powered, microphone preamps.
We also could caption the sound using a second-order Ambisonics microphone with 9 capsules. This would result in a better spatial resolution but also in a higher degree of complexity during the production process.
There are many ways to use Ambisonics microphones. We could arrange the musicians in a circle around the Ambisonics microphone positioning a 360° camera in the middle of the ring to capture a vivid 360° video performance. Another option would be to place the microphone like a traditional main microphone system (AB, XY, ORTF) in front of a stage, for example, in a jazz club.
The signals coming from the four capsules of the Ambisonics microphone build the so-called A-format, with which we won't work during the mixing and transmission process. The A-format consists of the four recorded signals coming from the four capsules. To be able to work with the audio file, we use dearVR AMBI MICRO to transfer them to the working format, which is called the B-format. In addition, dearVR AMBI MICRO offers an Ambisonics correction filter improving spatial accuracy when used with the Sennheiser AMBEO VR Mic.
To encode the A-format into the B-format we create an Ambisonics channel in our DAW. Then, we insert dearVR AMBI MICRO into the first slot to encode the signals coming from the capsules (A-format) into the Ambisonics B-format.
Within dearVR AMBI MICRO, we select “A-Format (AMBEO)” in the input section and “B-format FOA” in the output section. While the A-format consists of the four capsules, the four B-format channels are named W, X, Y, and Z. These four channels represent a microphone with a dedicated polar pattern, each of which is pointed in a specific direction. Channel W represents an omnidirectional microphone that records sound coming from all directions. Channels X, Y, and Z are figure-8 microphones that point in different directions. All combined channels represent a 360° sound field.
In addition to the adjustments described above, we can select the position of the microphone on the stand. Was the microphone basket directed upward or downward? Or was it headed forward towards the sound source? The mic placement is only available if you set the input format to A-format or A-format AMBEO.
We hope that this article helps you get a first impression of the possibilities of what you can do when working in Ambisonics. We showed you how to prepare your DAW for Ambisonics monitoring using regular headphones, how to rotate Ambisonics recordings, and how to encode recorded audio material using dearVR AMBI MICRO.