How to handle clicks in the audio

Clicks (buffer underruns) are the enemy when working with live digital audio. There can be several causes of these buffer underruns. We will go over them and look at ways to prevent them.

Windows Schedular

Especially with older CPUs (we have not seen this on the recommended CPUs yet), there can be problems with the Windows Schedular that cause clicks: When you have as many worker threads selected in the settings screen (or more) than the amount of logical CPU cores in the system, windows is running other processes on cores that also need to run real-time audio. Because of context switching, these cores need time to switch between the real-time audio processes and things like storage indexing, virus scanners, memory swapping etc.

A solution for this is to set the worker threads 2-4 threads lower than the number of logical cores. So, if the system has 12 logical cores, try 8-10 worker threads.

Audio Device Buffer

The audio device buffer determines the time between each moment the audio device presents and needs a new buffer of audio information. The lower this number, the lower the latency the audio device produces. But like the windows schedular problem, the lower this number, the higher the probability that there is an event on the computer that locks the CPU for a time that is long enough to cause buffer underruns. As a general rule of thumb 256 or 512 samples buffer should be good options to try.

Sometimes it’s not possible to use these settings, for instance when using certain Ravenna (AES67) drivers with 2202-07. If the driver can only be set to a value much lower than the recommended value (and this causes clicks) you can try the multiplier settings in the settings menu. When the multiplier is set to a setting higher than 1, we enable an internal buffer that takes multiple audio buffers, then processes them in 1 go after which it gives the buffer back to the audio device in small parts. To a certain extent, this emulates a higher audio buffer inside the LAMA Platform.