How to propagate ValeTreeChange to compound parameter assignments

I’ve followed the tutorial for uising AudioProcessorValueTreeState to store and retrieve parameters and attach to my GUI and all is fine. It’s a pretty small plugin.

However now I have a case where the parameter values will not be accessed directly in processBlock instead they will be used in a computation that I believe should not be part of the audio thread. In my case I will need to re-calculate IIR-filter coefficients when I change filter gain, frequency or q.

The solution I see is to implement my own subclass of the abstract AudioProcessorValueTreeState::Listener and then implement it’s parameterChanged and that’s fine. But it seems a bit overly complicated for just a few parameters.

Is there perhaps some smarter way to add callbacks directly on a few parameters in a PluginProcessor? In that case I intended to implement callbacks directly in the PluginProcessor instead of making a new class just for these few fuctions.