# BFD filter to mimic HPF at 40Hz



## zheka (Jun 11, 2010)

Hello,

Attached is the near field measurements of my subs (Epik Legends). As you can see, there is some sort of boost at 25Hz. That is the area where the subs typically run out of juice and begin to compress. What I'd like to do is limit the bandwidth to much more manageable 40Hz and up range. Is it something I can accomplish with the BFD? 

The reason I'd like BFD is because I already own one though I have no experience using it yet. 


thank you


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

See here - substitute “HPF” for the word “crossover.” :T

Regards, 
Wayne


----------



## zheka (Jun 11, 2010)

Wayne A. Pflughaupt said:


> See here - substitute “HPF” for the word “crossover.” :T
> 
> Regards,
> Wayne


Thank you, Wayne.

What if I do not call it a HPF? I am not concerned with the slope and , perhaps foolishly, with phase artifacts. All I am looking for is a way to sufficiently attenuate signal below 40Hz. What's the best way to accomplish this with BFD?


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

zheka said:


> What if I do not call it a HPF?


Not sure why you’d say that, since you already said a HPF is what you're looking for? :scratch:

All you need to do is open up the “Equalizer” panel in REW and start piling on filters until you get what you're looking for. With that panel, REW shows on the graph the electronic response of any filters you employ. When you get the attenuation curve you want, transfer the filter settings to your BFD.

Regards, 
Wayne


----------



## zheka (Jun 11, 2010)

Because after reading your post I realized it is probably wrong term to use.

You are absolutely right though, I should have tried to do something myself before asking for help.


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

No problem, a lot of people aren’t aware that you can “model” EQ filters in REW without taking any measurements. Just thought I’d throw it out in case you weren’t aware of that. :T

Regards,
Wayne


----------

