DSP crossover, anomaly on start and song change Options

[Ray_D]

Hi

I have written a digital crossover dsp for three way speakers using fourth order Linkwitz-Riley filters and a low shelf filter for boosting the bass.
The version with hard coded frequencies and gains (no preset) works perfectly and sounds great.
I subsequently wrote a version with a preset allowing for user input.
It works; but, there is a clunk sound for a fraction of a second on start up and when a song change is forced.
The frequency display also shows full bars for a short time.
No anomaly is heard when songs change naturally.
I would like to understand the function calls that happen at those times to help debug this issue.
I am also unfamiliar with .dll debugging techniques.

Thanks

Ray