Thinking about it this might be based on the electrical "rule" -90 degree phase shift for a capasitor and +90 for an inductor. this is purely electrically though. Somehow Hornresp streches this to -+180 degrees...

Half of a bass cycle is a VERY long time. How in the **** can it be shifted this long purely acousticly ???

My method of learning is through understanding.. Its not working right now

It would be much more understandable if mr Mcbean would add groupdelay instead of phase. I have also seen some speaker measurement graphs that also speak of phase but omit the amount of full cycles and round off to the nearest cycle.

Thanks for any mental help ...