highpass on a kickdrum?

[John_C]

Freeing up headroom by using high pass filters with minimum phase eq's is a myth and can be verified easily.

Because of the phase shift of the eq, when applying a hp filter you are boosting the frequencies right above the cut off or shoulder frequency. If you have a cut at 35 Hz, it's inherently boosting around 40 - 45 Hz.

If you take a broad band recording, run it through a 35 Hz hpf and notice the peak level before and after, you see you're loosing head room.

you say "because of the phase shift". how does that work to create a boost above the cutoff freq?

 

[Genius Gone Insane]

My kick HP entirely depends on where the bass is sitting...if I put the bass below the kick then I'm going to HP the kick near 60. If the bass is sitting around 120 then I'll HP the kick at 40 etc

 

[guitarguru777]

I HP on the Master bus at about 40hz

 

[waltz mastering]

you say "because of the phase shift". how does that work to create a boost above the cutoff freq?

With mp eq, the more you adjust for gain or the attenuation of a frequency , the more its phase changes, shifts or distorts (same thing). This transfer function is non linear and the phase shift around the cutoff makes constituent frequencies 'add up' differently as they are all shifted progressively by different amounts.

Here's a graph of a Low Shelf 200 Hz cutoff. +3 to +18dB shown. Q set to minimum.

..anyway this is getting a bit off topic..back to kick drums...