Just wondering something about these Boston Acoustic speakers from the VR line, this is particaually about the 975, but it also applies to the 965, and other powered towers in general. How do they sound when you do not use the internal subs, and instead use separate subs (like other BA subs, or SVS)? What about when you use ALL the subs, the included ones, and separates? Any cancelling frequencies? Also if you do not use the internal subs, do the bass drivers do anything (such as play lower frequencies from the amp), or are just dead silent? Thanks in advance for the info.