Any recommendations on a subwoofer to pair with the X7 and the EMU-X7 speakers, mainly for gaming and movies, doesn't need to blow the doors off, but would like it to add to games etc.

Hopefully, someone can help, shed a little light etc.   Had it 2 days, updated the firmware, if I touch the calibration under speakers the front left sounds "robotic" almost, anything other than the preset of 7.2ft will distort etc   Always more than one problem, wouldn't be any fun...