Re: Where the slave beater strikes...
Just to let you know, AXIS designed SONIC HAMMER beaters can be positioned so both the primary and slave hit off center.
99.68% of drummers do not have their bass drum beater hitting dead center due to the ratios produced by implied industry standards of pedal main shaft height- around 7.25" and beater length-around 8"
Half (center) of a 22" head is 11" The 99.999999% of us have our beaters extended above 4"
I gigged an 18x18 kick with a riser for almost a year, used that same riser on my 22" just b/c I had it. I can tell you hitting the 22" dead center 'did not' produce the most desirable sound.