Quote Originally Posted by davef View Post
Are you referring to the high level speaker inputs on the F12 with A370PEQ or the low level HPF outs?
Low level output, a while back I had a conversation with Brian and he confirmed the line out on the A370PEQ has a fixed 80Hz 12dB high pass filter build in while the low pass filter on the line in side can be either 12dB or 24dB slope depend on the setting..

I also found out there is another version of the A370PEQ offered by GR Research with modified low level line out with 100Hz -3dB q=0.6 (12dB) high pass filter, I guess it is used with the GR Research paper driver which can cross-over higher than the Rythmik aluminum cone?