Low cut filter at 50Hz with a 12dB/Octave slope

I wanna keep using this feature, but get rid of the EQ unit itself

Sorry, I'd assume that this means it's cutting 50Hz freq. by 12dB, but I'm not positive, nor do I have the slightest idea what they mean by octave slope

Basically I'm asking how much of what should I EQ out of my rig to simulate what this filter is doing.

Disclaimer: i searched some, and i have NO idea what im talking about when it comes to these numbers. I know 'gain, bass, middle, treble, volume' when it comes to my amps and EQ, thats about it.