HPF - together with preamp, enhancer, exciter?

[plangy]

Dear TalkBass,

First, big thank you for the ton of info regarding everything.
I am still curious about one thing - if the HPF setting should be somewhere around 40 Hz (lets not discuss the number) and the preamps has the bass section somewhere around 20-40 Hz, does it make any sense to use it, meaning bass boosting?
The same for the enhancers, exciters.

I am just thinking if it is reasonable to use any of the bass boost if I am going to filter it by HPF anyway.

And the last thing - sorry for my grammar, I am not a native speaker.

 

[Stumbo]

When you use a HPF, it cuts out subsonic lows aka "mud". So, if you set it for 40hz (or, better yet, at your cab tuning frequency), any bass tone control you use will modify the hz above that, allowing you to boost/cut the good stuff.

FYI, same with an LPF for the highs.

 

[plangy]

Thanks for the answer.
If you say my HPF should be better on my cab tuning frequency, does it mean I should also want the filter slope to be set more steep to be able to filter out as much "mud" as possible?
Just to be sure - the cab tuning frequency is the value mentioned as the frequency response (the lower one)?