I suppose anyone with an EP 500, 600 or 800 could chime in with advice please. I have my pre pro bass management settings as follows:
-All speakers set to small
-M80s and VP 180 at 60 Hz
-M22s at 80 Hz
My question comes from varying guidance on the setting for the physical crossover knob on the sub itself. Even the user manual does not make perfect sense to me:
"If you are using the Bass Management crossover menu settings in your A/V receiver or processor, turn the subwoofer crossover control to the setting at or just above the highest crossover point you selected on your A/V receiver menu, i.e. for a 90-Hz or higher receiver menu setting, use the 150-Hz setting."(why not 100?) "For 70 – 80 Hz on the A/V receiver’s menu, use 80 Hz on the sub, and so on." This would tell me that in my case, set it at 80. I know one school of thought, however, is that when using bass management in the pre pro or receiver, the sub's crossover control should be at the highest setting (150 in the case of the EP 800). The "average" of these two recommendations is the 100 setting -- maybe that's the answer for me! Is this where the discussions of "roll off" and "smooth integration" come into play? I trust your collective experience more than my not-so-golden ears? Any thoughts (scientific or otherwise)?

If you are using a pre/pro or receiver to handle bass management, then you want to get the sub crossover knob out of the way. Crank it to the highest setting, or to bypass, if you have an older EP series.

If the receiver is doing it's job properly, then you want the sub to get its crossover out of the way, so they don't interact. That means setting it as high as possible.

Smooth integration is more about when you don't have a crossover in the receiver and you're sending full range to the speaker and sub. The speakers will start to roll off at some point. The idea is to get the sub to start picking up at that point.

With a crossover in the receiver, it does the work. If the lowpass filter in the sub is set too near the point of the receiver there can be interaction between the two.

So with a modern receiver set it high. I don't know why Axiom documentation says different.

Thanks for the early responses. By the way, I just watched Alan's old EP500 setup video. He recommended either 80 or bypass, suggesting one tries it both ways to see which sounds better. Is choosing the 150 setting on the current Axiom amps essentially doing a bypass?

Essentially, yes.

Another reason to leave it at 150, is there can be unique content in the LFE channel up to about 120 Hz, that isn't originating from the other crossed-over channels.

Blu, yes, with a modern receiver or pre-pro doing a precise crossover, there's no good reason to involve the(usually less precise)low-pass internal sub filter in the process. Set it as high as possible to get it out of the way of the receiver set crossover frequency. On those subs with a bypass setting or an input that bypasses the low-pass filter, use that.

i know this is slightly off track but how do you like your front 3 crossed over at 60hz? i have the same front 3 but crossed over at 40hz and love it. just curious...

Thanks everyone. Looks like the smart axiomite goes with highest frequency setting (or bypass if available).

Solar- You're living on the edge. Guess I'm too conventional. I don't think going down to 40 would stress my amp (Rotel 1575 -- 500 watts per channel into 4 ohm load). I should try it.