Hi Larry,
In comparing the X-LS Encores with the AV-1's, the Encores definitely have stronger, deeper bass since they use a larger 6-1/2" woofer compared to AV-1's 5-1/4" woofer. Also, the Encores have a flatter, smoother frequency response than the AV-1's, while the AV-1's have a warmer, livelier, sound without sounding over bright or harsh. From what I have read, the AV-2's , which use a second woofer in an MTM arrangement, really sound great. They have stronger bass, play louder, and have higher sensitivity, but have a 4 ohm impedance.
Ron