high-efficiency loudspeakers

@kqvkq with regard to Quad ESL 57s the recomended maximum amp size was 45 wpc as I had them and when Quad brought out their 405 current dumping amplifier they stipulated that you had to put current limiting resistors in it to limit the amp to 45wpc when using the 57s. I'm afraid I know this to my cost as twice I had to replace bass panels as I thought I would be smart and not use the resistors.

Ken Shindo gets the hammer green color that he uses in some of his amps from the Altec Lansing 604C. 

He actually once used a pair of 604Cs in a pair of floor standing cabinets that were being sold for $33,000 in a Manhattan audio salon, maybe two summers ago. 

The pair I have are in an identically sized pair of cabinets. I added the Mastering Lab crossovers, the whole package costing me $3,300, a mere tenth of what the “Shindo” pair eventually sold for, to some unsuspecting Wall Street sucker no doubt. 

I’ve had my pair for 35 years. Every 7 or 8 years or so I figure there must be something better, I go shopping for a month or so and decide well, yes, this or that may be better but is it $50K better, and the answer is always decidedly no. 

The speakers are 103DB. I run them with a pair of Julius Futterman OTL3s, converted to triode. The depth and detail are outstanding. 

I’m basically a happy camper. 

I own Spatial Audio M2 Turbos - 94dB?  They're wonderful.

I have a pair of the new Spatial X2s on order.  92dB? Clayton Shaw and the world tell me they'll be wonderfuller.  Impatient?  Me?

I run the M2s with a PS Audio Sprout.  It's wonderful, too, and what? 33w/channel?  And a good 'nuff DAC, and Bluetooth.  Lively and fun with the M2s.

I also play my music very loud. I have a pair of  Source Loudspeaker Technologies 7211's with 2 H/VS 10 Subwoofers and I'm very happy. I have a DB meter on my ipad and I play in the 92 DB up to 98 range with ease. Don't hear much about these speakers but at $2400 and $1800 each for the sub's there a very good deal. Built in  South Windsor, CT by
John Sollecito. You can give him a call he's very happy to talk to you about your music needs. 

PWK Khorns for decades. They have a deep sound stage, when properly voiced with good quality amps. Quality is key. And most of my listening is done slightly below 90dB.

In the last 60 years of this hobby I've heard systems that sound as good or only different, but none better. And none that delivered a "live in the next room" sound.

I have Martin Logan ESL's in another room, which are extremely transparent but sterile. I like the MLs, but they are not very involving. They provide a good reason to talk about and discuss amplifiers with other audiophile. Good material for helping selling amps in audio rags. Had Maggie's, Quads . . . same issue despite throwing tons of watts at them at any level. Odd, that I still like the MLs.

Hello all,
First, wtf, you're going to LOVE the Decware. I've been playing around with that amp since 2004. Done more mods on it than you can shake a stick at. Never felt a need to go the true DHT route. ( And I've heard a bunch of them ). It's just that good.
But of course you need the right speaker to mate with it. Let me throw my two cents in for the Decware HDT. Been using that also since 2004. That combo replaced a very high end system of Sonus Faber Guarnieri Homages/REL Stadium III subs driven by solid state electronics. Wouldn't dream of going back.
The HDT does all the things exceptionally well that single driver loudspeakers are noted for. Plus its WAF is very good. That combo gets plenty loud enough for me.
For the record I have no stake in Decware other than being a happy customer for a long time.
Cheers,                   Crazy Bill

Daedalus Audio speakers are very efficient and beautiful to behold too.

While there is no "best", I will say that Legacy Audio comes close..I've heard most of the above mentioned brands, and Legacy is the one that captures my heart and soul. A very efficient speaker not needing a lot of power to drive, but at the same time will handle a huge amount of clean power. Even the Legacy bookshelf speaker (Studio HD's) have a awesome sound, and have sound much larger than they actually are...they also score well on the wife factor, with their custom finishes she will find something that will fit her taste..the Rosewood finish did the trick for my better half.
www.legacyaudio.com

@bbarlow The Spatial Audio X2's look very promising indeed, and they could turn out to be real contenders.  I'll be watching the thread on A. Circle carefully.

Twoleftears:  I promise to report back.  Unless I keel over from their wonderfulness...

There are several manufacturers of hi-efficiency speakers, nut not many that are commonly discussed on this forum.  There is no "best", just what's best to you.  Mating a speaker to an amp for best sound involves a lot of factors besides the sensHere are some more manufacturers:
- Audio Note E,J, K or their DIY counterparts from ANK kits
- Avantgarde Acoustics - extremely efficient and pricey
- Bob Crites horn designs - the Cornscala will change the way you think about horns
- Cain and Cain - single driver speakers
- Classic Audio speakers
- Coherent - made in Canada.  Look beautiful but I have not heard them
- Coincident
- decware - all great
- Devore O/97 and O/93 - outstanding speakers
- Omega - the best single-driver speakers I have personally heard
- Pi
- Reference 3A - you will see a lot of PP amps using these
- Rethm - the Bhaava is an amazing, affordable point source/rear loaded horn speaker w/ an active bass driver
- RL Acoustique - Lamhorn
- Shindo - upscale Klipsch designs, sound wonderful but $$$
- Silverline - some models
- Spatial - the M3/M4 Triode Master versions.  Quite affordable
- Trenner & Friedl - some models
- Tyler Acoustics - some models
- Volti Audio - 21st century reworking of the classic Klipsch horn designs
- Tekton & Zu - not my cup of tea but a lot of guys love these

I may have missed some.  There's also a whole world of older/classic speakers from an age when high-efficiency was a requirement and not a choice.  Here are a few suggestions:
- Altec Lansing - Specifically the models 14, 15 and 19
- Cain and Cain - single drivers, highly regarded, company recently demised
- KEF
- Klipsch - all classic Klipsch models w/ horns are very efficient
- Snell E, J, K or the /II models - the genesis of the Audio Note line.  If you want to see if AN speakers will work in your room for cheap, grab a pair of these in good condition
- Tannoy - some models, although I always found these to be much less efficient than listed by the specs 
- Von Schweikert db99 speaker - a recent model from a current mfr

I'm sure that I missed someone's favorite speaker vendor.  If so my apologies...

The real test for a high efficiency speaker is if it can be powered by an 1W amplifier and reproduce the entire frequency range (including bass) with 1W or less. Here is one review that covers such a system: http://theaudiobeatnik.com/linear-tube-audio-mz2-s-originally-released-microzotl2-0-teresonic-magus

In addition to Teresonic, I would add Auditorium23. I heard a pair at CAF, and liked them a lot. But with the caveat that they were in a small room.

I prefer 10 foot wide burl wood horns with dual 30 inch woofers powered by a .127 watt vintage telephone amp….cloth covered wire from 1918…sounds awful but looks nice.

wolf garcia :   Good post , I have similar  Bacheaudio-002

Several people have mentioned the subjective nature of finding "the best" of anything, and I don’t think anyone disputes that. It still remains a journey we undertake willingly, because it’s so much fun. Over the last days I’ve read the Posts and thought about the concept of "Best" and about how much I continually learn about measuring sonic performance. Education never stops. "The Best" is a moving target. With that said: efficient speakers and am I happy with them?

Early on, Aric of Aric Audio shared with me that he was about to launch the first of several speakers on his website. At the time, my interest and focus was on structuring the tube system to maximize it’s ability to blow me away every time I powered it up. The undertaking was highly successful yielding 3 preamps and 3 amps. Then I started thinking about speakers. To cut to the chase, I bought a set of his Dynaltos which are 30" floor standing 3 ways, crossed masterfully, which (I live in rural Nebraska) with freight, came in under $4K.

These speakers are incredible.
The build quality is excellent, fit and finish makes you not even notice it, and the sound -- that’s why we do this, right?

I find them very articulate due to the ribbon tweet and its marriage to the mid because of his unique crossover design It sounds like one speaker -- even up close. To me, they also have both a dynamic and a 3-dimensional presence and throw a sound stage that’s wide. He rates them at 95db @ 1 watt/1 meter. My SE can drive them with ease with all of its 18 watts yet they maintain composure when driven hard by my Enigmatic mono blocks which are 120 watts a piece. Additionally they produce very low bass for a 10" in a "smallish" sized cab. Their footprint is only 11" X 13" but they sound like they are much bigger than that.

It’s a bit ironic that what I believe to be among "The Best" are truly "Unknowns" at this point because they haven’t officially been rolled out yet. Stay tuned. You might be hearing a great deal about these speakers.

 "The Best" is a moving target.

*S*  Absolutely...typically, what you have....until you fall out of love with it when 'Better' appears....

wolf_g, yeah, and the Edison cylinders just complete the Experience.....  (...the crystal tuners' whisker forces one to turn off the Mazda lamp, which invariably knocks it off signal....as a source, a notable fail....*sigh*....) 

Classic Audio Loudspeakers T3.4 or the Bigger Brother T1.5 Field Coils.
Dynamics are scary, the speaker is so fast, smooth, and emotionally engaging.

Over the holidays I took delivery of a pair of Daedalus Audio Apollos. Far and away the best speakers I have ever owned and among the best I have heard at any price. Simply gorgeous and sound incredible. I have done some writing about them here:

 https://forum.audiogon.com/discussions/daedalus-audio-apollo-speakers

and will continue to add impressions to the thread. Very efficient, easy impedance load, high power handling, easy to place in the room, big, bold, natural sound. I am running them with an LTA Ultralinear amp which is a great match. 

I have a pair of Shindo 604 Field Coils at 16ohms/101+sensitivity. They are pretty special and I don't see moving away from them. I also don't see moving them period as they're the size of a washer/dryer set.

Note that my still surprisingly great sounding Klipsch Heresy IIIs cost (from a reputable Ebay seller/dealer with factory warranty) about 1500 clams including shipping. For a beautiful sounding 99db efficient 3 way I  think they are unique little speakers that will raise the roof with my massive 12wpc single ended tube amp. Unfortunately it does require payment in actual clams, which need to be refrigerated. 

Yes, currently using Hawthorne silver Iris drivers in a open baffle, sounding very very nice now as my kt77 gold lion tubes in my amp have settled in very nice.With high efficiency speakers I recommend all tubes or tube pre and SS amp.Most of these speakers have horns or compression drivers.For me I won't buy a horn loaded speaker but you may like them .

I have Horning Eufrodite Ellipses which have 98db efficiency.  They sound really well with my Frankenstein 300b monos and First Watt SIT-3 amp.

hocheye  Hawthorne uses a horn loaded coaxil so you did buy a horn speaker

One thing about the Heresy IIIs that's interesting and noticeable when looking at them (which I often do since they're in front of my eyeballs when listening) explains part of the musical coherence they display in spades...measured from the center of the tweeter horn to the center of the woofer is only about a foot...to the edge of the woofer much less of course...all due to the mid horn being narrow top to bottom and placed right on top of the woofer (even has a cutout in the same radius as the woofer to help in the proximity), and the tweeter horn right on top of the mid. For a 3 way that's pretty close, and the design works amazingly well with tseamless blending of the drivers...a good thing.

I am a fan of many high-efficiency systems, but, most are systems built from high efficiency drivers and custom cabinets and crossovers and not complete packages.  I like some vintage drivers and a few modern drivers that are either straight out replicas of old drivers or are modern updates of old drivers; these however, are crazy expensive (e.g., G.I.P, Cogent, Goto).  

Of the modern, complete systems, my favorite are the Charney Audio systems utilizing full range drivers in back-loaded horn configurations.  Until I heard the Charneys, I did not think that a single driver system could really be a complete speaker capable of playing all sorts of music very well.

For a fairly low-cost high efficiency system (albeit with a built-in amplifier for its bass driver), I like the Rethm Bhaava.  At a substantially higher price level, I like the Avantgarde systems that also use powered bass drivers.

For not so high efficiency speakers, I like the entire line of Audio Note speakers, The 093 family of Devores, Trenner and Friedl speakers, Classic Audio field coil driver speakers and Horning.

I know they aren't the "best", but I really enjoy my Legacy Audio Focus 20/20 speakers. I've heard better speakers, but purchasing a used set of these was the best price / performance compromise for me. I also have a pair of Klipsch klf-30 speakers and a pair of Klipsch heresy I. I've gone through and replaced the crossovers and all of the drivers in the heresy and the crossovers mids and tweets in the klf-30s with parts from Bob Crites.  They are both very listenable speakers.

By the way, tseamless isn't an actual word.