How to handle slight variation in MCLK Frequency

[Flavia]

Hi, we have an industrial application with audio where we need to have dynamic control over MCLK frequency on the Xcore-200 MC audio board (This is due to a special application on the Host that has some variation).
The output of the PLL seems clean and the audio glitches happen a within one second of the change (not necessarily immediately).

Are there any constraints or buffering we can add to the app_usb_aud_xk_216_mc example application to allow for this?
How could we implement this in a glitch-less way?

[Ross]

How much variation are we talking? The Async feedback system should handle this, within reason.