Adding Tectonic speaker to existing speaker design

[gcl]

I am looking at adding Tectonic TEBM65C20F-8 3.5" speaker to existing speakers as a experiment for better off axis response . Any played with these? Do I need to seal these off from existing speakers.

[billfitzmaurice]

You need to seal them and create a new crossover. The first isn't difficult, the latter is.

[fpitas]

I'll add: where you locate them with respect to the other drivers will determine if you improve off-axis performance, or turn it into a hash of lobes.