I have finished a project of column based upon Martin's design rules.
I was using the Fostex FE127e and was not happy with the result.
I have since replaced the FE127e by the FX120 since it could fit the existing design.
The Fe127e lacked control resulting into some bluring.
Yes the FX120 is much more expensive but the sound is cristal clear instead.

The box design or its practical construction are not to blame, the issue was actually related to the Fe127e.

Would anyone have similar unsatisfactory experience with the Fe127e?

I think that the limited displacement amplitude of the Fe127e is the origin of the problem. Could someone comments on this.

Regards, Jacques Candé