The reason that it's there is that not all users need it. So that begs the question. If you turn it off and your woofers start pumping, or you have acoustic feedback, you need it. If not, you don't.
The roll off at the bottom of the audio band is usually pretty subtle, though a few are actuall down at 40 cycles, you can verify this for yourself by turning it on and off and listening. On the other hand, it will most certainly have a marked effect on phase response in the audio band, and the jury is still out on that one, as well. So it all comes back to trying it both ways.
The roll off at the bottom of the audio band is usually pretty subtle, though a few are actuall down at 40 cycles, you can verify this for yourself by turning it on and off and listening. On the other hand, it will most certainly have a marked effect on phase response in the audio band, and the jury is still out on that one, as well. So it all comes back to trying it both ways.