On many occasions I have been asked for a simple tutorial how to set up a recording session for an ambisonic microphone. This is a step by step guide for setting one using Zylia microphone on both Windows and mac OS. You can use that guide as a reference for any microphone, you just need to use proper A>B decoding plugin, channel setup and interface setting.
This is very basic manual, that doesn’t go into the science of the ambisonics.
ZYLIA has it’s own audio interface, so you don’t need to use any additional hardware. To connect use the USB 2.0 cable (male A > micro-B).
For monitoring purposes you can use the built-in interface of your workstation.
If you work on mac OS the Core Audio (native mac OS sound system) will support you with option to create aggregate interface (ZYLIA as input, build-in as output). Here you will find manual for setting this properly.
(15.04.2019) Unfortunately at this moment on the Windows you cannot monitor audio during recording. The driver gives you only mute dummy interface output.
(03.02.2020) You can monitor Zylia on Windows machine using additional software. Here is the descripton of this walkaround.
Download and install latest Reaper for your system. Open the application.
Go to Options > Preferences and go to the Audio/Device section.
On Windows select: Audio device: ASIO, ASO Driver: Zylia ZM-1, Enable inputs should be ticked on and the first device set to Microphone 0, last device can be Microphone 19 (ZYLIA ZM-1 has 32 inputs but uses only first 19).
On mac OS choose your aggregate device in the Preferences window.
Place an empty track in the session. Click “routing” button on the track stripe on the mixer at the bottom of the screen. In the routing window set the track to have 20 channels (Reaper lets you set only an even number of channels). We will use 19 of them.
Next, select FX from the mixer stripe of your track. Find ZYLIA Ambisonic Plugin and choose it.
In the plugin you can choose your model of microphone. There are 3 different ZYLIA microphones available at the moment: ZM-1-1C (discontinued), ZM-1-1D (discontinued) and ZM-1-3E. Choose your version. Set proper ambisonic parameters form AmbiX (3rd, ACN, SN3D). Define position of your microphone on the set (Upright/Upside Down/End-Fire) and the rotation/elevation of the microphone. All of those settings are just for monitoring/rendering purposes, and they work in real time. You can change them also after recording, they don’t affect the input signal.
For setting the volume I use O3A Gain and O3A Meter. On the end of the chain place O3A Decoder – stereo if you have stereo or headphone monitoring setup or 5.1 if you have surround speaker setup in studio. In the stereo plugin choose Panner if you use speakers or Basic head if you monitor with your headphones.
You can experiment with other tools from Blue Ripple Sound O3A Core such as Virtual Microphone which can give you a bit different stereo render than the Decoder Panner or you can test other plugins for monitoring. It’s worth to try SSA a3Monitor plugin, sophisticated AIIRADecoder from IEM or SPARTA from AALTO.
I hope this manual will help you starting your first ambisonic session.
The cover photo of this article was made by Mateusz Smoczyński from Atom String Quartet.