They are quite distinct from each other. dB/watt is the sound pressure level converted from 1 watt of electrical power signal. For 'speaker specifying purposes a 'speaker of 90dB/watt is said to be more efficient than another of 85dB/watt. The numbers have little relation to the quality of sound produced. This parameter is used by audio engineers to design their products and similarly applied to audiophiles to mix and match their different choice of poweramp/speaker combination in a less haphazard manner.
speaker effiency
hello can someone please tell why speakers with the same effiency, mind you different in that one is 4 ohm the other 8 ohm, that one would play loader then the other.the one that is 4ohm (thiel cs1.2 )is the one that plays loader. the other is gershman x-1.also next week i am adding the sw-1 sub.it is a passive sub.it has the same effiency as the others 87 or 88.my amp is ocm 200 (100 wpc ).will it get worse (if that's the word )