What is Word Clock?
For two or more digital audio devices—like effects processors or digital preamps—to work smoothly together as a group, there needs to be a master device that sets what’s called the word clock rate. All the other devices (the slaves) must follow this clock rate.
This is necessary because each digital audio device has its own built-in clock generator, which provides the basic timing for processing audio data. While we’re on the subject, the process of moving media—whether it’s video, film, or computer animation—also needs to be synchronized.
When multiple devices are working together, they need to have their basic clock rates in sync. This synchronization is achieved using the word clock, which is the base clock signal that allows information to flow accurately between devices.
Simply setting all connected devices to the same sample rate isn’t enough, because even small differences can cause noise, interference, or even complete signal failure. These timing errors are called jitter. An external word clock tells all the devices exactly when the clock pulses start and stop.
All digital devices must reference the same clock—otherwise, one of two things will happen, depending on the specific devices involved:
- The receiving device detects incoming audio data that isn’t synchronized with its own clock cycles, so the data is rejected. The result? No audio passes through.
- The receiving device detects incoming audio data and tries to play it, but because of slight differences in clock timing tolerances, pops and clicks are heard in the audio.
How Does Word Clock Work?
A Word Clock is a steady square wave pulse that operates at the sampling frequency. Word Clock signals are often generated by oscillators, which use quartz crystals that resonate at a precise frequency.
The digital audio device locks onto this pulse and uses every maximum and minimum value of the wave as the ‘tick’ of the clock, marking where each slice of audio begins and ends. It’s crucial that this clock is as stable and free from variations—called jitter—as possible. Irregularities in the clock signal can lead to less high-frequency detail, poor stereo imaging, and an overall dull sound.
Word Clock becomes even more important when connecting two or more digital audio devices that send signals to each other. All of them must synchronize to a single ‘Master Clock.’
If you don’t set up the Word Clock correctly, you might end up with no signal at all, or signal errors like drop-outs, pops, clicks, or even loud bursts of white noise that could damage speakers. Since most live sound equipment now shares signals digitally, it’s essential to understand how to set up and manage your clock.
Simple digital setups, like an audio desk and a remote stage box, usually handle the clock settings automatically. Most digital stage boxes are designed to be clock slaves, taking the clock from their digital connection with the desk. Most desks default to using their internal clock generator. Even if you change the sample rate on your desk from 44.1kHz to 48kHz, it shouldn’t cause any problems in these situations.
Does the Word Clock Improve the Sound?
Originally, a word clock is simply used to sync two or more digital devices together. It doesn’t act as a converter, nor does it contain any components that can directly improve your sound quality.
However, using a word clock is important to prevent potential problems that can arise when your digital gear isn’t properly synchronized. As mentioned before, issues can occur if you don’t use a word clock—so while it won’t make a good signal sound better, it is essential for avoiding failures in sound quality.
Getting a better or more expensive word clock for your studio will improve the stability of your signals. While it won’t enhance the sound itself, it will provide more stable clocking, which results in reliable audio without problems like jitter. This means you’ll get great, consistent results without any unwanted issues.
Conclusion
This was a brief overview, but we believe we’ve covered all the essential information about word clocks for both newcomers and experienced mixers. If you look back through the text above, you’ll notice that we bolded certain words and phrases containing “digital.” That’s because you’ll need a word clock if you’re using only digital devices, or if you’re combining digital devices with a digital mixer.
If you’re sticking with the tried-and-true analog signal using regular cables, then you don’t need to worry about clocking. But if you decide to use any digital devices, you’ll almost certainly need a word clock for your studio.
If you have any questions about this topic, please let us know in the comment section below. We’ll be more than happy to provide you with answers!
