well i'm pushing these with an adcom 555 which pushes 325 watts into 4 ohm.what i've read here they say i could not turn them up all the way in a 14 by 20 foot room but i can and i notice that 105 sound pressure on these sounds way louder and cleaner on these so the ?is sound presure = sound level?and by the way i can go to 110 sound pressure in this room with this setup.anyway DEF LEPARD never sounded SO GOOD