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The digital audio revolution of the last 25 years has brought about exciting changes. For most live audio engineers, the external racks with compressors, reverbs, pre-amps, etc., are gone, and in their place are software effects that reside as software on the audio console or an external server. Also missing in most live environments are the long analog cooper snake runs that go from the stage to front of house. Used in its place are Ethernet or fiber cables that carry digital audio. Audio console settings can be organized and saved into scenes or snapshots for quick reference and recall as songs, speakers, and needs change during use. Virtual soundcheck has transformed the practice environment to give live audio engineers a chance to hone their mix while giving an opportunity to sit down with band members and singers and have a genuinely collaborative approach to mixing live.
Your digital audio system is only as stable as the clock that syncs it.
The digital audio revolution has also lowered the price of full-featured audio consoles for worship services and ministry events. However, quite a few churches and ministries are experiencing new problems with an expanded digital audio environment and network. Pops, clicks, or dropouts occur at seemingly random times and moments, causing frustration to audio engineers, church staff, and regular attendees. Technical leaders check connections, cables, and firmware, but these clips, pops, and dropouts still happen. Frustrations mount. Fingers are pointed. Instead of allowing this level of conflict and mistrust into our technical ministries, church technical leaders need to learn more about the importance of a word or PTP (Precision Time Protocol) clock.
A word clock synchronizes digital audio devices by providing a standard reference for sample rates. It pulses a square wave signal at the sample rate (44.1 kHz, 48 kHz, 96 kHz, etc.). Each pulse indicates the start of a new sample. When multiple AD/DA converters (analog to digital/digital to analog) are interconnected, the clock's synchronization keeps the converters from having timing errors. When a digital audio device experiences a timing error, the audio system will experience an audible clip, pop, or dropout. A word clock is primarily designed for a local, self-contained audio environment like a studio or a smaller-scale live deployment. In a smaller church setting, the digital audio console can provide the master word clock for all the system's digital devices.
Clocking keeps the chaos in check.
A PTP clock is like a word clock, providing a standard reference for digital audio devices. However, this protocol syncs clocks on an Ethernet network to the microsecond or even to the nanosecond level. The PTP clock is essential for networked audio systems where timing is an absolute must, such as large or larger-scale live audio setups or broadcast environments, where complex routing and processing across networks are needed. An example of where a PTP clock is necessary is in digital audio networks, where multiple devices are accessing distributed audio across longer distances. This is where it’s vital to have equipment and network infrastructure (like switches and cores) that are compatible with a PTP clock residing on the network. Depending on the size of the network, an external, rack-mounted PTP clock can be the best solution instead of the front-of-house audio console or a computer running something like Dante Controller. The external clock is usually located in a secured area, always powered on to provide a continuous sync even when other devices aren’t currently on. This ensures that the audio network always has a reliable sync source as devices join the network.
Clocking is an important part of our churches' digital professional audio systems. As more digital capabilities are added at all price points and budget levels, it’s crucial to understand how digital audio systems operate and where clocking for all AD/DA equipment comes from in your system.
Understanding clocking is critical for church techs to deliver clear, dependable audio.
Knowing these things about your church’s digital audio system will help you as you partner with the pastor to tell the good news of Jesus Christ to as many people as you can with a reliable and dependable audio system.
