It's a question of two things: (1) the expense of high component-count passive crossovers, and (2) the linearity required of drivers in the first place. If equalisation is cheap, linearity needn't be as central a focus in driver design/selection.
And then there are the very few speakers with NO CROSSOVER AT ALL due to judicious driver selection, such as the:
Frazier Super Monte Carlo, An 8 inch mid/woofer with a Helmholtz tuned forward facing for a port & a Piezo tweeter using the natural roll off of each. 1 watt = 90+db. (maybe 93 db?: with 18 watts RMS in stereo I got 112 db in a 12X14 bedroom). Bass below 50 Hz? No. Treble above 16 KHz? No. But seemingly OK in between. No claim on +- db of the frequency response. Jack Frazier (from TEXAS & friend of Paul W. Klipsch) died in 1988 and all his speaker designs were only in his head. He did make a living building speakers. I will say that these sound OK, much better than you would expect for being designed to not have a crossover. This is in a secondary setup for background music for my mothers bedroom. I bought mine new (based on what my ears told me, fully subjective [In 1977 was starting to learn about better stereo equipment, still uninformed but I liked what I heard]) shortly after I bought my ADVENT 300 new. Good with low power, like the ADVENT 300's internal amp. I am curios and plan to stick them into my main system & hook up DSP to them in the upcoming year and see how bad or good they really are (and how good they can be made to be). I suspect that with NO CROSSOVER WHAT SO EVER the DSP will have a lot to do.
And then there are the very few speakers with NO CROSSOVER AT ALL due to judicious driver selection, such as the:
Frazier Super Monte Carlo, An 8 inch mid/woofer with a Helmholtz tuned forward facing for a port & a Piezo tweeter using the natural roll off of each. 1 watt = 90+db. (maybe 93 db?: with 18 watts RMS in stereo I got 112 db in a 12X14 bedroom). Bass below 50 Hz? No. Treble above 16 KHz? No. But seemingly OK in between. No claim on +- db of the frequency response. Jack Frazier (from TEXAS & friend of Paul W. Klipsch) died in 1988 and all his speaker designs were only in his head. He did make a living building speakers. I will say that these sound OK, much better than you would expect for being designed to not have a crossover. This is in a secondary setup for background music for my mothers bedroom. I bought mine new (based on what my ears told me, fully subjective [In 1977 was starting to learn about better stereo equipment, still uninformed but I liked what I heard]) shortly after I bought my ADVENT 300 new. Good with low power, like the ADVENT 300's internal amp. I am curios and plan to stick them into my main system & hook up DSP to them in the upcoming year and see how bad or good they really are (and how good they can be made to be). I suspect that with NO CROSSOVER WHAT SO EVER the DSP will have a lot to do.