Other things being equal--which they usually aren't--I'd certainly go for the more efficient speaker. The more efficient, the less power you need and the better potential to accurately reproduce dynamic contrasts. The less power you need, the less the voice coils will heat and the less the speakers will compress the sound. The less power you need, the more headroom your amp will have and--if you like to play loud music--the less likely you'll be to damage sensitive tweeters. Also, the more efficient your speakers, the freer you are to try a wider range of amplifiers. And so on.
In the interests of full disclosure, 35 years in the audio hobby has shown me that I more often enjoy efficient speakers. The four pair of speakers I have range from 92 to 100 dB.
It's also significant that one manufacturer's 86 dB may be almost the same as another's 90 dB. Most don't cite the parameters of the tests that established the efficiency rating they quote. The most important is whether the rating specified is for an anechoic chamber or for typical in-room conditions (the former is typically 3 dB less than the latter). The next most important is efficiency over what frequency bandwidth: the 86 dB speaker that maintains that efficiency over most of the audible spectrum may, overall, be as or even more efficient than the 90 dB speaker that was measured only at 1 kHz or over a relatively narrow bandwidth (say 200 Hz to 6 kHz).
Another issue is what sort of impedance curve is characteristic of a given speaker. An 86 dB speaker that never dips below, say 6.5 ohms impedance may be far less demanding on your amp than a 90 dB speaker that dips to 3 ohms.
As I said, "other things" are seldom equal, but when they are, the higher the sensitivity ("efficiency" is the term we commonly use, but actually refers to another parameter) the better.
Happy listening!
Joel.
In the interests of full disclosure, 35 years in the audio hobby has shown me that I more often enjoy efficient speakers. The four pair of speakers I have range from 92 to 100 dB.
It's also significant that one manufacturer's 86 dB may be almost the same as another's 90 dB. Most don't cite the parameters of the tests that established the efficiency rating they quote. The most important is whether the rating specified is for an anechoic chamber or for typical in-room conditions (the former is typically 3 dB less than the latter). The next most important is efficiency over what frequency bandwidth: the 86 dB speaker that maintains that efficiency over most of the audible spectrum may, overall, be as or even more efficient than the 90 dB speaker that was measured only at 1 kHz or over a relatively narrow bandwidth (say 200 Hz to 6 kHz).
Another issue is what sort of impedance curve is characteristic of a given speaker. An 86 dB speaker that never dips below, say 6.5 ohms impedance may be far less demanding on your amp than a 90 dB speaker that dips to 3 ohms.
As I said, "other things" are seldom equal, but when they are, the higher the sensitivity ("efficiency" is the term we commonly use, but actually refers to another parameter) the better.
Happy listening!
Joel.