I have the VSM's, and mostly listen to 'rock' (although I prefer to call it virtuoso guitar music, which could range from jazz to classical to bluegrass to funk to screaming heavy metal). I have a large room, sit about 8-9 feet away from the speakers. I have no problem achieving 90 db levels (as measured by radio shack meter) at my listening position, and that's with my preamp only 25% of the way up.
Of course, volume is far from the only consideration. Even on lousy rock recordings, detail, soundstaging, etc. are excellent (to the extent that they can be, given the recording). As far as bass, I had a sub and sold it. Partly that was because it wasn't a great sub, and wasn't fast enough to integrate well with the VSM's. However, I don't think I need a sub for what I listen to. Several people have asked my where my sub is, even though I don't have one! No, the Merlins even with the BAM will not 'shake the family jewels', so to speak. But with the bam AND THE RIGHT AMPLIFICATION/PREAMPLIFICATION/SOURCE (capitalized on purpose, for emphasis!)you will get more bass than you would think possible from a 6.5 in. woofer. If you like techno or something that requires wall shaking bass, then you will need a sub.
Of course, volume is far from the only consideration. Even on lousy rock recordings, detail, soundstaging, etc. are excellent (to the extent that they can be, given the recording). As far as bass, I had a sub and sold it. Partly that was because it wasn't a great sub, and wasn't fast enough to integrate well with the VSM's. However, I don't think I need a sub for what I listen to. Several people have asked my where my sub is, even though I don't have one! No, the Merlins even with the BAM will not 'shake the family jewels', so to speak. But with the bam AND THE RIGHT AMPLIFICATION/PREAMPLIFICATION/SOURCE (capitalized on purpose, for emphasis!)you will get more bass than you would think possible from a 6.5 in. woofer. If you like techno or something that requires wall shaking bass, then you will need a sub.