Humm, @dallasjustice describes it somewhat differently.
"The JBL M2 is 2 way speaker system without a passive crosssover. There is a protection circuit built into the speaker which is designed to protect the D2 compression driver from DC and excessively loud low freqeuncy noise. Harman recommends an 800hz crossover for the JBL M2.
https://www.audiosciencereview.com/...nse-digital-crossovers-w-subs.2369/post-66200