Well, I just revised the two designs for the three way and two way crossovers. I added a noise gate and slightly reduced the already very limited FIR filter. But, making sure noise is removed will help more than the phase filtering in this use case. I chose -80dBFS, but considering the signal detection threshold is set to -60dBFS threshold, you can play with both of those to figure out the best balance and agreement. After all, if the speaker trigger is at -60, you might want to filter all signal less than -60dBFS, which is signal at less than 0.1%, which is around the noise floor for the amp unit anyways.
I chose peak for the noise gate instead of RMS to fully limit noise at that amount rather than an average. If you are going to use the compressor to also limit the volume on the high end, then that module needs replaced with the RMS filter as the RMS will allow transient amounts on the top end to exceed the max value set, which can help with dynamics of the audio playback. For the ADAU1701, there isn’t really enough to do RMS and Peak, unless you want to further reduce or eliminate the FIR filter, which you could also do. On a two way, that is easier.
If you are using 1 board to do 4 outputs to 2 bookshelf speakers, then eliminate the FIR filter and copy the rest of the signal chain for the other two channels.
Edit: Made a four-way and dropping it here. made the extra changes so that one volume know would control both speakers and updated the output channels, as that would have been a source of confusion for people.
The four way is made for speakers where the person sets them up to be able to bi-amp the speakers. By setting it up to bi-amp, you can do the control of both speakers externally and you can mount the KABD inside an enclosure by itself, separate from the speakers. And that allows for the speakers to be usable with other external components sometime in the future.