Perhaps your subs didn't play low enough. Subs should only provide 80hz to 20hz, or even 40hz to 20nz, depending on how low your mains will play. Anything from 80hz and lower is non-directional. For M22's 80hz to 20hz works well. For M80's, you could use the 40hz to 20hz settings.

https://docs.google.com/spreadsheet/ccc?...amp;usp=sharing