To Gonk, if a preamp has Bass Management internally like most do, why does a subwoofer manufacturer build in a crossover freq dial on the back of subs systems?

Are there preamp and or receivers on the market that don't offer Bass Management and that is the reason for the crossover dial on the back of the sub?

Laslty, most web sites that I have visited suggest setting the crossover point at approximately 10hz above that recommended by the speaker manufacturer. On my speakers, B&W indicates these speakers can handle down to about 44hz. Based on the sites I went to, that would mean setting the Bass Management crossover freq to 55hz...???? Why would one allow the fronts and center to handle the bass that low when I could easily set the crossover through the preamp to say 70 or 80 and allow the sub to everything up to that level instead of everything up to 55 level?

Does my logic seem correct make sense?

look forward to your reply.

thanks in advance

Dm

If you put a sub in a stereo system or any system without a relatively modern surround receiver or processor driving things, you are not likely to have bass management (the RR2150 being the only exception that I am aware of), so there is still some value to retaining the ability to manage bass at the sub (assuming the sub offers the option of bypassing that management).

Some people like to keep the crossover point as low as possible to make maximum use of their speakers and to keep the sub tied to lower frequencies (which are less directional in nature, making the point source of the sub less likely to point itself out).