Back up people. Wattage rating only means (well supposed to mean anyways) what the maximum wattage the speakers can handle without any damage for passives, it does not by itself indicated how loud it's going to be, otherwise for actives it indicates the amp wattage that's built into it.
For instance (not specifically picking on you photon, but using your post); putting 30 watts into a speaker can be more than you'll ever need. My example would be the JTR Noesis 212HT which has a sensitivity rating of 101dB/2.0v, which means one watt of pink noise and that speaker will play 101dB at one meter. At 32 watts it'll be around 116dB at one meter and with two speakers at 30watts each it's ~119dB at one meter.
@OP: The rating you want to look at is sensitivity, more so than wattage (for passive speakers). If they are actives, then hopefully they give you the max SPL.