Paul McGowan of PS Audio just finished a detailed blog series on this. It looked quite thorough and sensible, although I don't have a sub to try it.
You can check it out at:
http://www.pstracks.com/pauls-posts/woofer/9990/
He posts his blog once a day and the subwoofer series was done in a week or two.
You can check it out at:
http://www.pstracks.com/pauls-posts/woofer/9990/
He posts his blog once a day and the subwoofer series was done in a week or two.