All things being equal, the more efficient speaker will also produce a higher sensitivity rating. The only reason that it would actually produce a lower SPL is if it was a very low impedance and the amp could not properly drive it. While most amps do not have a problem with higher impedance loads, dropping the impedance or using a speaker that is highly reactive can give some amps fits. The more difficult the speaker load, the less options that you have in amplifiers. Thiel's have always been known as "power suckers" even though their sensitivity rating is reasonable. They are a little tougher to drive than most other speakers and as such, require an amp with TRUE "hi-current" output. As to Jim's statements about efficiency being measured as a percentage, he is correct. As we've all seen, sensitivity and efficiency are often incorrectly interchanged for each other. Most speakers are VERY, VERY low in terms of efficiency even though you might see what we normally think of as being a very high sensitivity rating for them. Sean >
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 )