Do No Harm ... well the least harm anyway

Why would you want to limit bass to a full range speaker system?

I'm also in the camp that prefers to run my main speakers full range, and just use to sub to augment the bottom octave or so.   Some male vocals can go down near 60hz, and are best reproduced by your main speakers so the fundamental notes plus their harmonics all come from the same place, where they stand a much better chance of sounding like a single coherent music wave. .  Just my 2 cents.

+1, @cleeds

Unless your speakers sounds distorted, I would not limit any high or low frequencies. If that’s the case, I would look at the alternate amplification (amplifier) and preamp.

OK, thanks all. My reasoning for wanting to do this is to limit cone movement of the 2 full range drivers. Since they have no crossovers at all, they must play the delicate midrange as well as the thumpy bass. I figure if I can cut out the cone movement of the bass, the mids won't be smeared by that back and forth motion. I do use subs (Velodyne DD15's) next to each speaker. Since the main speakers are away from any walls their bass is not as strong as in a conventional room. My listening room is large as it encompasses the living room, dining room, kitchen and den all in an open floor plan. I have the subs lowpass set to 55Hz.

Yes, I also realize, the other option is to leave it alone. I'm just not sure if it's better to go down this path, or not.

I can see why you'd want to use subwoofers with your speakers, but I'd still run the speakers full range and set the low pass on your subs really low, which is really what usually sounds best.