Efficency- Low vs. Hi?

Im trying to figure out the point in speakers with very low efficency, for example my speakers which are 4ohm and 86db. As far as im concerned they have no benefit besides being able to spend much more on an amp to get them to move. Right now they sound shut in, boring and thin with my Cambrdige Integrated amp, which is rated at 65 watts 4 0hm. I do not really have the budget to spend hundreds MORE on a power amp just to get these speakers to sound as good as a high efficent design on a lower powered amp, such as my current cambridge. So what are the benefits to having power hungry speakers? Why should i have to spend tons of money just because my speakers are designed with poor efficency?
Your low efficiency speakers will play deeper in the bass region than a high efficiency speaker with the same box size. There's a tradeoff between bass extension, high efficiency, and small box size. You can have any two of the three, but not all three.

If you're comfortable with larger boxes, then you can expect deeper bass, higher efficiency, or some combination of both.
Interesting question that's been asked before. SEARCH for more info.

There's no particular benefit to low sensitivity in moving-coil speakers that I know of, and low sensitivity is never a design GOAL, AFAIK. A designer may fall in love with a particular midrange driver that happens to be low in sensitivity; everything else has to be built around it. A designer sets as a goal high power-handling capability; that requires higher-order crossovers, which as a negative affect consume more energy than single-order crossovers.

There are lots of reasons speakers are low in sensitivity.

I must ask--why did you buy those unnamed speakers?
Isnt it great to have Duke posting and helping on this site! I always look forward to his responses!
This is a great question and not simple to answer. One benefit to lower eff. is in tone. It is easier to come up with a warm full tone than say with super high eff. horns which need tubes to make up for their bright ballance. There is allways a system synergy going on with any combination. None is better,none is wrong or wright. Its all a trade off. I have the exact same speaker numbers and amp power that you have and have no problem at all with volume or openness. The problem in your setup, is the current ability of the amp. Not the power output! the speakers present a load your amp is not happy with-just and only a system missmatch. A 50 watt BEL mk5 would blow your speakers apart without breaking a sweat because it has huge current. The power rating is way over rated because it never takes into account the load in real world use. Also just try a high power amp with super eff. speakers and be ready to race out of the room. Those low power amps are just a better match. System matching is by far and away the most important part of the entire chain. Low price equipment well matched will beat super super expensive equipment that is not well matched.

I forgot to mention my speakers are the PSB stratus Mini's.
Not to pick on you Dave, but I wouldn't consider the Cambridge being low powered at 65 watts. My amp delivers 2 x 25 watts......
Its all about synergy except with the most non linear loads. There are some speakers that just won't be satisfying without power. Apogees come to mind, you can read a million threads on how they really need a fairly powerful high current amps because of their impedance drops. On the other hand I have a fairly low power 40 watt Consonance tube amp driving 88db 6 ohm speakers (VR2s) as long as you don't ask it to blow your head back they have very pretty sound and stage well. In addition I have rock the house as loud as you can take it sound from a big efficient horns with much less refinement, but still pleasing synergy with a 50 watt Mac solid state. If you really want full sound from your system you have to dump the Cambridge or your speakers they are clearly mismatched for that purpose.
You should be less prone to audible grunge from some of the low level electrical noise sources, and this can save bucks on noise reducing / isolating gadgets and whatzits.
Also if you go tubes all those big glowing bulbs look cool.
Else, besides what was said previously about getting good bass from a smaller box, I don't know of an upside.
I'm not familiar with the PSB line but don't they have some floor standing models that are more efficient? If you keep your amp but change speakers, won't you get a lot more "bang for the buck"? I just looked on ebay and saw a pair of PSB Alpha T speakers with a "buy it now" price of $298. Efficiency is listed as 91 dB which means they should play as loud with your amp as your Minis would play on 200 watts/channel. What about those Status Golds that everyone raved about?
The stratus series IME is hard to drive in general and has to be pushed a bit to open up. I was able to drive a pair of stratus silvers with a 60W rotel amp. This was a seperate amp that weighed 20+lbs though. The silvers didn't really shine until I got a Bryston 3b-st.

Amps are a good buy used. If you can use the Cambrdige as a pre I would pick up a 100W rotel amp from as few years ago and try it out. You can add a real pre later if you want. If that doesn't help then the Mini's aren't for you and just move on.
There are so many medium and high efficiency speakers with excellent sound that I see little reason to use low efficiency speakers. Only exception to this statement is if you gotta have something like a big Soundlab electrostat or Acoustat vintage electrostats.
Sometimes high efficiency speakers have larger peaks and dips in their frequency response, and between the drivers at their crossover points, and less low bass extension.
Otherwise for low output amps and integrated amps, good high efficiency speakers are the way to go!
Audiokinesis- THanks for the reply, I wasnt aware of the bass being able to go deeper with a less eff. design, and no , I wouldnt be bothered with a larager box. A larger box design would most likely what id look at it if i ended up selling these speakers,as they seem to have a bigger warmer sound than smaller monitors.

Mahandave- Yeah, I kind of wasn't thinking when i made this amp/speaker match. I had originally planned on using this amp with a pair of Ascend Acoustics CBM-170 , which actually made a great match, but in the end i wasnt satisfied enough with the speakers so i sold them and bought the mini's. I bought the mini's unheard( i know i know) because of how impressed i was with my old pair of PSB IMage 2b's, so i figured that id like the mini's as well, and this was true to an extent. Shortly after buying the mini's i came across money troubles and wasnt able to buy a sub like i had planned, or a more powerful amp which is needed to drive these speakers.

Jeffreybehr- Ahhh, that helps me in understanding why anybody would build a non efficient speakers, thanks. And, i bought the mini's based on how much i liked the PSB sound from past experiances, thinking that low efficiency just meant I had to crank the volume more . Now i know better.

Brainwater- yes, Duke is an inspiration to us all and a hero to millions.

Mechans- Synergy. This was also something i wasnt aware of untill AFTER poor mismatching proved to be disastrous. And im guessing that the impendance dips is mostly the problem here, not just the low sensitivity. From what i remember my speakers have a pretty low dip in the lower midrange.

Jeff_jones- Are you recommending tubes ?

Elgordo- Actually, ive had some problems with resonance from the standmounts in the image series ( image 2b) that caused me to stop listening and take them in for a refund. I cant imagine how bad the alpha series would be in this regard *shrugs*. I appreciate your recommendation, though. And its not about playing loud, hell i cant stand turning my cambridge up 1/4 of the way because of how bad it sounds. I just want a full sound at low levels, high spl's are of little concern. But i do agree with u that a more efficient speaker would let me get more out of my amp, instead of spending more on the amp itself.

Satch- Well, 65 watts into 4 ohm, which is pretty low considering how hungry these speakers are. Or maybe its the current thats low? hmmm...

Nkturner920- Im not going to argue with you on that one, the minis seem very hungry for power. The bad thing though, is that right now im switching my system between two different rooms, one being a 9'11" x10'6" bedroom, and the other being a 20x20 living room, and when listening to the mini's in the small room i have to listen very carefully to hear all the details. I want a speaker that will sound good in both rooms. I was also considering the Bryston... untill i saw how much they cost used. too expensive IMO to pay that much just because my speakers have low effiency.

c123666- So far, IME i agree with you. If i had the money, then buying a big juicy power amp wouldnt be that big of a deal, but for me its more logical to just get more efficient speaker design, and not worry about my amp. As far as speaker with more sensitivity go, what would be a good choice to look at? Ive always like the way my Polk computer speakers sound, so maybe looking at some of the older,more high end models would be a good idea?

I forgot to mention that my musical tastes include Iron Maiden ( probabaly my favorite band), Metallica, Green Day, No Doubt, 80's New Wave, SOME Rap, even some classical and jazz every now and then. AS you can see my musical preference is very wide, so please keep them in mind if you want to give me recommendations, thanks.

I agree about the mismatch. My view (with all its biases):

PSB Stratus Mini: described as having great bass (for size)

Cambridge Audio: UK company with the "British sound" (warm)

Not having heard either of these, I'd expect an overly warm tonal characteristic that essentially hides the midrange that may be what you've described as "shut-in."

My guess is that efficiency is not really the issue though one can make some generalizations (a dangerous idea at best). That is, that lower efficiency designs tend to be more controlled hopefully with a more neutral tonal balance while higher efficiency designs let through more of the speakers inherent characteristics which includes colorations (the peaks and such mentioned before). IMHO, higher efficiency designs have a more immediate quality / quick response that provides a sense of openess (certainly not "shut in").

My inclination is to get the warmth from tubes rather than solid state components designed to sound warm and match them with high efficiency speakers that give immediacy and openess. It's just one approach. There are many others. Thinking through what direction you'd like to go with help from others at stereo shops might be useful.
Your taste is pretty bass-heavy. Grinding, crunching, woofer-throwing music isn't generally regarded as the stuff hi-eff is made for. Inexpensive, hi-eff, big bass? Hmmm. . .gonna have to think about that one.

For that musical taste, I'm thinking a used 150-watt+ amp. I don't think your amp is gonna push the power you need with any speaker. Just one opinion.

The midrange is actually MUCH too forward, anything with distorted guitar and/or yelling vocals is utterly unlistenable. Much too grainy ,harsh fatiguing whatever you wanna call it. This type of music takes up about 90% of my music collection. Its not the room either because i tried my system in two different rooms, one being large and one being small, and in both rooms the sound was almost identicle. However, what i meant by "shut it" was that the soundstage, imaging and detail sound restrained, almost "lazy". The bass is also very lean and weak sounding, even in a small bedroom. Im really confused on what the problem might be. Thanks for your response.
Dave123etc. - I'm not reccomending tubes per se. I've got similar musical tastes to yours and also low efficiency speakers. Tubes were part of the answer for me, but a lot of folks would like solid state just as well or better and would be able to find a more cost effective solution going that route.
Back to your original question, I went with a low efficiency speaker only because that was the one that happened to knock my socks off. Ida preffered it if I fell for a higher efficiency speaker, just didn't work out that way.
Good Luck!