41:35, I believe the B6 like many D&B subs runs higher than 100hz in "standard form" i think 125 or 140 ish depending on the model. The 100hz filter is therefore actually "lowering" the low-pass filter rather than raising it. The "INFRA" will shift that emphasis lower obviously... Im not sure any of this would affect SubAligner's operation none the less. On a side note related to this, I was taught many years ago, that D&B's philosophy regarding the use of their low filters, was to place EITHER a cut in the tops with the subs in "Full range"/standard mode, OR, run the tops full range and place a 100hz filter in subs but not both (though real world scenarios can take over) - I find that a number of longer term D&B user are familiar with this but not so many who are less familiar. Many manufacturers have similar "philosophy" it would seem but this was one that came back to mind. With newer D&B arrays with which I have limited experience so far, it would seem that it the above theory may alter somewhat as those boxes run down very low with a lot of control..... Im gonna stop rambling : please keep up the excellent work - I enjoy the insights and the smaart theories and thought concept have been very helpful in practice for me - CHEERS!