I heard the 15B's today. I thought my SE-1's went deep. Those 15B's are amazing for a bookshelf speaker. IMO,no subwoofer needed for two channel listening. If I were doing a theater setup with them then I would use a sub.
Man cave-Marantz 8012, Oppo 203, 4K ATV, Sony XBR-75X940E, Bluesound Vault 2, Harmony One, 2 Paradigm Monitor 9's, CC-390, 2ADP 390's/190's, 2 PDR 100's,
4 SVS Prime elevations. B&W P5. Living room- Yamaha 2010, Bluesound Node 2, Paradigm SE-1's, Zone 2-Paradigm-Stylus 370-SM
Bedroom- Samsung UN60ES7100F, Oppo 103D, Pulse Mini, JBL Bar Studio, ATV3 and Harmony 650