Zylia 6DoF Recording System

Beitrag von Eveline Vervliet

Introduction

The Zylia ZM-1 microphone is a 19-capsule microphone array used for 3D/360 audio recording in 3rd-order ambisonics. It allows the user to record sound scenes and separate single sound sources though a combination of microphone array technology and digital signal processing algorithms. It’s easy to connect to your computer with a USB cable and compact in transportation.

The spherical microphone has 19 capsules that each have an omni-directional polar pattern and that use Micro-Electro-Mechanical Systems (MEMS) technology. The durable casing features an LED ring status indicator. It is capable of recording at sample rates of 44.1 and 48 kHz and 24- bit sample depth. Gain adjustment controls in steps of 0.5 dB from −12 dB to +32 dB are provided. The microphone is 6.1 in high and 4 in in diameter. It weighs 15.5 oz. The ZM-1 has an integrated desktop stand and it can be mounted on microphone stands that use 1⁄4-in and 5⁄8- inthreads. It connects to computers using a micro-USB port in the base.

This article first describes the 6DoF volumetric audio capture system with its respective software and then moves on to show possible applications for streaming and binauralization.

Software

For proper functioning of the Zylia ZM-1, you must install a driver. Download the driver specific for your operating system here. The following software is available:

Zylia 6DoF Recording Application for recording with multiple Zylia microphones
Zylia Ambisonics Converter for converting from A to B format
Zylia Control Panel with some information on the connected microphone
Zylia Streaming Application for setting up your live audio streaming with the Zylia microphone
Zylia Studio for recording with one Zylia microphone

Zylia Studio is a software application for recording and processing from the Zylia microphone. It can be used to balance and pan the multichannel recording and to separate it into individual audio tracks for use in a digital audio workstation (DAW), if required. Two separation modes are available, a virtual microphone mode and a high separation mode. The first of these mimics a directional microphone and allows any part to be isolated from the three-dimensional space. The high separation mode uses an additional process to mimic the behavior of a close microphone, reducing ambient sounds and background noise and giving even better sound source separation. The audio can be stored as PCM WAV files or using a lossless compression that reduces the size by half. The software is compatible with Macintosh, Windows, and Linux operating systems.

A PRO version of the software is available as a VST/AU plug-in. This provides spatial filtering and signal separation tools within a DAW and gives the user access to virtual microphones with different polar patterns and characteristics in post-production. A number of different group and surround sound presets are provided.

Download the software here. Note, that for some applications licenses are required.

An Ambisonics converter can process convert multi-channel audio into b-format higher-order Ambisonics. It also supports FuMA or ACN channel ordering and SN3D or N3D normalization. It is also compatible with YouTube’s ambiX and Facebook’s TBE formats. The converter is available as a standalone application or as a VST plug-in.

Workflow

Recording

Recording with the Zylia microphone can be done either in the standalone application Zylia Studio or in a DAW with the Zylia Studio Pro audio plugin. As a DAW, Reaper is most recommended.

Conversion

To use the recordings on other platforms or for applications like videos, the recordings have to be converted to an Ambisonics B-format. You can either use the standalone application or the Zylia Ambisonics Converter plugin.

There are several standards in the ambisonics world related to channel ordering and normalization levels. The most used one is the ambiX standard. For this, you choose the following settings: channel ordering ‚ACN‘ and normalization ‚SN3D‘. The following video from ZYLIA explains the workflow for converting a recording.

Stream on Zoom with the Zylia Microphone

Stream on Zoom with multiple speakers

Download Reaper session template

Use recording with Binauralix + BITalino R-IoT

The raw recording from the Zylia microphone will contain of 19 channels. The converted file in B-format in 3rd order will have 16 channels. First encode the B-format in a software like MultiPlayer-mini before integrating it with the open-source software Binauralix.

In the following demonstration video, I open the 3rd order B-format of a Zylia recording in multiplayer mini and send it to Binauralix over Blackhole. The I communicate with Binauralix over OSC in Max. In this way, I can use the BITalino R-IoT sensor to control the listening orientation in Binauralix in real-time.