If you experience crackling/static when adding your interface into BEACN Mix create our first suggestion is to check your interfaces support website for driver updates for that specific interface. Some interfaces (for example: Scarlett solo and 2i2) do not come with any update checking or program that checks for driver updates so you could be a few driver revisions behind the latest release.
We have also seen issues when devices have different sample rates which cause a crackling/static sound to occur between devices. The most common fix we have seen is making sure that the input devices match the sample rate of the BEACN Devices as closely as possible.
To do this, you will want to open your mic interface's control panel (ex. Focusrite control panel) and find the option for sample rate and make sure its at 96000, if it has an option for 32-bit that would be best to apply as well.
If your interface does not have a control panel but does have a DAW (Digital Audio Workstation) that was provided with it, you should be able to adjust the sample rate there. Most DAWS will put the options under "Preferences" and then audio settings. Then same as above making sure to request 96000. There are plenty of free/trial DAWS that you can use to request the sample rate.