SoundGrid 201 Part 2: Clocking in a SoundGrid System

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Please note: Completing the SoundGrid 101 certification course is a prerequisite to taking the SoundGrid 201 test.

Clocking in a SoundGrid System

Generally speaking, an audio clock is a time signal used to synchronize devices which communicate via digital audio signals. Clocking prevents audio jitters and other unwanted noises and artifacts.

In any digital audio network, one device is designated as the clock Master. The other devices in the network will be ‘Slaves’ to that device. The clock Master distributes the clock signal to the other devices in the network.

SoundGrid distributes the clock signal to devices in the SoundGrid network using conventional Word Clock or Digital stream sources, or digitally, through an Ethernet connection, using SoE (Sync over Ethernet) – which uses the same Ethernet cable that carries the audio and other network information for sync.

Each SoundGrid-Compatible I/O device may use one of multiple available clock sources. These various clock sources belong to one of the following categories:

  1. Internal
  2. Digital clock
  3. Word clock
  4. SoE

Internal

This is the clock internally generated by a SoundGrid I/O device. All SoundGrid-compatible I/O devices have clocks built-in and each can serve as Clock Master.

Digital

Some third-party devices, like digital mixers, can send Master Clock data using a digital audio connection.

For example, DiGiCo consoles can send clock data using a MADI connection. In that case, when for example using a DiGiGrid MGB (MADI to SoundGrid interface), the MGB’s clock source will be set to Digital, while all other SoundGrid devices in the network will be set to SoE.

WordClock

A dedicated WordClock device can be used to generate the Master Clock signal.

When using a dedicated WordClock device, it will be connected to one of the SoundGrid I/Os equipped with a WordClock input.

This SoundGrid interface’s Clock source will be set to WordClock, while all other SoundGrid devices in the network will be to SoE.

SoE – Sync Over Ethernet

Sync Over Ethernet is Waves’ proprietary protocol for passing a clock signal to devices via the SoundGrid network. It’s is a solid and simple way to sync up devices on your network and works like most audio clocking formats do – a Master/ Slave relationship between devices.

SoE does not require additional cables to synchronize devices, it uses the same cable that connects the SoundGrid interface to the SoundGrid network.

Also, SoE eliminates the need for an additional external clock device, because all SoundGrid-compatible I/O devices have solid clocks built-in.

When using SoE, one SoundGrid-Compatible I/O is set as SoE Master, then all other I/O’s and devices are automatically set to SoE Slaves.

After a device is made SoE Master, it will start broadcasting clock sync frames 10 times per second to the network.

All slave I/O’s, servers and other SoundGrid devices will get this frame and will start following the master clock.

Sync Over Ethernet

SoE was developed from the ground up by Waves and was designed to be sample-accurate.

Waves also implemented a jitter reduction mechanism into all physical SoundGrid I/O’s, as well as the SoundGrid Driver to guarantee maximum accuracy.

There is no sound quality difference, or extra stability gained by using an external WordClock device instead of SoE.

The only reason to use a WordClock device for sending one output from one’s personal favorite external clock to an I/O device on the SoundGrid network. The other devices on the SoundGrid network will still synchronize via SoE.

CONTINUE TO PART 3