Spkrplus is correct in his differentiation of efficiency and sensitivity. Ask a speaker manufacturer what the "efficiency" of a model is, and in all likelihood, THEY DO NOT KNOW. It is a very complex thing to ascertain. I recommend that when you are seeking specs on a loudspeaker, you look at sensitivity, an impedence plot(rather than a nominal value), AND a plot of the phase angle. Phase angle is the most underappreciated spec in this whole argument. By, looking at the impedence and phase angle plots, you can often garner more information than you realized. By looking at a few specs provided by a manufacturer, we are often misled that a given loudspeaker will be easy or difficult to drive. In the real world, many speakers play a lot different than the spec in the literature. Another thing, if you can find out which drivers are used in the speaker, you can often go look at an spl(and impedance) plot(from the driver manufacturer). While this doesn't factor in the effects of the crossover, it can often tell you a lot. Example, if a driver's sensitivity is 88 dB/2.83V over most of its operating range, peaking at 92 dB/2.83V @ 1500 Hz, you can best believe the number you will be fed will be 92, when actually the number is more like 88.
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 )