Hi Topten,
Your Focal 807W are around tested 88db efficiency, about normal. The worst tested impedance is 4ohm between 100hz and 200hz, while this is not too nasty a load by itself for a good 4ohm say 50-100w tube amp. You have to add to that, it is tested also to have a negative phase angle of -45 degrees at 100hz also, that would give with 4ohm impedance load a combined EPDR (equivalent peak dissipation resistance) of around 2ohms.
While a tube amp will drive this and sound ok'ish, that bass region around 100hz will sound much more punchier and tighter driven by an amp with good current drive, 100w-8ohm solid state that can almost double to 200w-4ohm.
Cheers George

