How to read speaker sensitivity rating?


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When reading the sensitivity rating on speaker specs, does a lower number mean the speaker is easier to drive than a speaker with a higher number? Such as a speaker rated 78 db would be easier to drive than a speaker rated 102 db?
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mitch4t
Post removed 
Mitch4t.
Are you just pulling our legs ?
After looking at your systems I find it hard to believe you wouldn't know this.
Well over 100 discussions.
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Z-man,
Not pulling your leg here. the reason that I'm asking is
that I own several pairs of Infinity Kappa 9 speakers. They
are notorious amp-killers. I read the specs on them and it
says 102 db. Well the logic seems that if everyone knows
that those things are impossible to drive, the higher number
must mean harder to drive speakers. I am considering
purchasing a pair of Zu Dominance speakers. The sensitivity
rating is 101. I read an article about them being driven at
CES by a twenty watt tube amp. Well if the sensitivity
rating is only 1 db off of the rating of the Kappa 9,
something doesn't add up. Viridan noted that the impedance
would make a difference. The Zu speakers are 6 ohm and the
Kappa 9 are 4 ohm. I've always known that the lower the
nominal impedance of a speaker would make it harder to
drive, I just never understood the sensitivity thing.

Also, if you look at any of my previous posts, never have I
had a discussion of speaker sensitivity. I'm very sincere
about my lack of knowledge in this area. I posed the
question here because I do not want to make a $40k error out
of ignorance. The Zu Dominance speaker is a custom order
and there are no dealers that stock them so that I can
audition them. I'm trying to gather as much info as I can
in order to make an informed decision before I commit. So,
it's pretty much as I've always thought, lower impedance
ratings pretty much will determine the amount of muscle that
you would need to drive the speaker. In some threads around
here, it seemed that sensitivity ratings were thrown around
quite a bit as a big factor in the difficulty in driving a
speaker.

I'd like to try tube amps, and I know that the high powered
tube amps cost an arm and a leg, and I only have an arm....a
small arm. So it's important for me to make sure I get a
speaker that will play loud with serious bass when powered
by a tube amp. If you've checked the room size my system is
in, you'll see that the speaker will need to be able to
deliver some serious spl's.

Also, I checked my history of posting here and have seen
with a lot of consistency, that I've always posted a barrage
of questions prior to purchasing an item. With every
addition to my system, I find that I have posted lots of
questions on this forum about that item. Amazingly, every
time I don't post a question and I buy something, the
purchase turns out to be a clunker.

I'm more of a music lover than an audiophile. I've never
rolled a tube in my life. I don't know how to use a
soldering iron and I wouldn't dream of attempting DIY
project. By being here 10 years and asking lots of
questions, I've gained quite a bit of knowledge about audio.
But, also every week I read something here that reminds me
of how much I don't know.
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Sensitivity, like most other specs is somewhere between misunderstood and meaningless.
Without some other information, like some idea of maximum power handling and phase angles at frequency, sensitivity is just another number to hit back and forth over the net.

If your 100db sensitive speaker can handle 20 watts before the smoke gets let out, that is a much different animal than the same speaker with a max power handling of 400 watts.
Likewise for phase. If the speaker were a (mythical + flat) resistive load that would be a completely different kettle of fish than a similar sensitivity with a 3 to 20 ohm range and some wacky phase angle at the impedance minima.

By itself? Sensitivity is not worth much as a single number.
The Kappa 9's, when used with their "extended/normal" switch in the "extended" position (which iirc seemed to be the most commonly preferred setting), are conceivably the most difficult speaker load ever devised by mankind, at least among home speakers.

In that mode they go down below 0.8 ohms at multiple bass frequencies, where lots of energy is typically required. I know of no other speaker that comes close to doing that, although I believe the Kappa 8's are not too far behind. The "normal" mode is not quite as severe, but still very challenging.

I don't know what their phase angle behavior is in the bass region, but it wouldn't surprise me if it was significantly capacitive, adding to the severity of the load.

I can't imagine that a Zu speaker would be anything like that.

Regards,
-- Al