How to read speaker sensitivity rating?

I am certain that the specs. on the SPL ratings for the Kappa 9's are off by a long shot....CERTAINLY not 102db with 1 watt of input. I owned a pair about 25 years back, and would say they are more in the area of 83 db SPL at 1 meter and 1 watt input. I remember being in a room with some monster amps pushing them, and watching the meters on the amps jumping around between 200 and 700 watts, and the speakers were certainly not hitting levels in the room much beyond 105db or so. I also found the same specs. you mentioned on the Kappa 9's on a search on the web, and here they are:

Nominal Impedance: 4 to 6 ohm (recommends amps that can go lower)
Power Rating: 60-340 watts RMS
Efficiency: 102 dB SPL @1 watt, 1 meter
Crossover Frequencies: 80Hz, 800Hz, 4500Hz
Frequency Response: 29Hz-45kHz +/-3dB
Physical specs:
1x - SEMIT Supertweeter
1x - EMIT Tweeter
1x - 3" Edgewound Voice Coil Polydome Midrange Driver
1x - 5" Polypropylene/graphite Diaphram Polygraph
2x - 12" Cast Frame , L/C Tuned Woofers

It also shows their impedance to be 4-6 ohms, but they certainly dip WAY below that. Play a 1khz test tone through your Kappa 9's, use an amp with accurate wattage meters and give them 1 watt... Measure the SPL output from a meter away from the midrange drivers using an affordable Radio Shack SPL meter, and I bet it will read somewhere in the low 80db area. These speakers need a LOT of power to hit 102db SPL, The Zu speakers certainly do not.

.
Bug,

Yes, those are the exact specs that I used, which is why this
whole thread started. I bi-amp my Kappa 9's with four 900
wpc @ 4 ohm monoblocs. I did not understand what those specs
meant, but I do know that they looked very similar to the
specs that I read on the Zu Dominance. It was mentioned that
the Zu Dominance was being driven with authority by a 20 watt
tube amp. The Kappa 9 would vaporize a 20 watt tube amp.
The Kappa 9 specs posted on the web are what I've been using
as a comparison chart when considering other speakers. So,
all I've needed to know all along was that those Kappa 9
specs posted on the web are wrong.
.

Almarg -
Thank you for the explanation of "phase angle".

Typo. Another company spec sheet, if accurate.[http://www.infinitysystems.com/home/products/product_detail.aspx?prod=CS969000&CheckProduct=Y&Language=ENG&Country=US&Region=USA]