How important is the efficiency of a speaker to you?

@invalid --

That's not to say it can't be great match sonically. 

@phusis  It is not a myth, it has to do with the low output impedance of solid state amps.

@atmasphere wrote:

I look at it this way- if you can’t drive it well with 100 Watts (in most rooms), its a problem.

+1

... and 1000 Watt amps that sound like music don’t seem to exist although class D is getting close with amps that can make 600 Watts or so.

Whether or not there’s a generality to your claim above, I can’t say, but I was surprised to learn that a 600W class A/B power amp from MC² Audio was perhaps even more "musical" sounding than a 30W class A ditto from Belles (which was a great amp) - that is, driving a 111dB horn/compression driver combo connected directly to their terminals (i.e.: actively, sans passive crossovers). Nothing sterile, tonally lean, mechanical or bright sounding about the Brit, I can tell you that, or whatever you’re implying about high power amps sonics. To boot its inherent noise level (in fully differential balanced mode) is slightly lower than the Belles (unbalanced), even with a 32dB vs. 26dB gain. I feared it would have been the other way ’round.

Btw. it’s 8 ohm EV DH1A drivers (that can also be had in 16 ohm versions), but without the intervention of passive crossovers, added to +110dB sensitivity and the amp being limited to run the load from ~600Hz on up, it’s a piece-of-cake job for an amp if ever there was one. Show me an amp running a 16 ohm load, full-range and looking into a passive crossover that will be running in cruise mode the same way. Not going to happen.

It’s not that I need that much power in my setup (also falling in line with the first quoted part of yours above), but I wanted to use the same amps in my 3-way active system from top to bottom, and ended up "replicating" the one used on the subs to begin with - one that turned out to be great sounding full-range as well (which I expected, given their reputation). As they say: if it sounds great, it sounds great.

@invalid wrote:

The amount of solid state amps that sound good with high sensitivity speakers is also limited, that’s why a lot of people choose set amps with these types of speakers.

Another generality, indeed this one is a myth that has gone on forever. From my experience it holds little to no bearing (I can imagine it would have been an issue back in the very early days when SS amps likely sounded like crap, or certainly worse than today), but you’re certainly allowed to take fuller advantage of a low wattage SET design when driving very high efficiency speakers, and such a combo can indeed sound fantastic. The inherent noise level of such amps sees some filtration through passive crossovers. Actively, another matter, and it’s also why I prefer SS amps in that constellation.

@daveyf  : Trouble ( if any ) with the whole subject  that is confirmed through the thread posts is that each one of us have our each kind of target for home MUSIC reproduction and even several of us just do not have targets about.

In my opinion and before to look for efficiency/amps and the like is to be very specific the kind of MUSIC/sound each one of us want it I think that this is the main and critical factor to decide the: MUSIC reproduction sources, transducers, electronics, room treatment, cables and the like even our seat position and the kind of chair to listen sessions.

R.

Example: even its inherent importance of speaker impedance phase no one name it and this is something to take care when we are choosing an amp

@rauliruegas Actually this has been brought up in this thread.

The amount of solid state amps that sound good with high sensitivity speakers is also limited, that's why a lot of people choose set amps with these types of speakers.

Dear @daveyf  : It seems to me that if you put together some vali with facts and knowledge levels on speakers it looks as some way or the other we need something that just does not exist and we are looking in a transducer that makes all to be posible: there is no single or"  surrounded " perfect speakers/transducer and never will.

In the other side some of those gentlemans with good speaker knowledge levels have not the same good knowledge levels about amps/electronics and this fact makes everything more complicated to really have a good conclusion.

Example: even its inherent importance of speaker impedance phase no one name it and this is something to take care when we are choosing an amp we need to know the speaker impedance measures/curve and its phase down there.

Topic per sé is endless..

R.

@invalid   You bring up a great point. The signal to noise ratio is a factor with most gear. Tube gear is likely to be noisier than ss gear. The question is how important is the tube noise through the more efficient speaker to the listener. I'm not so sure that it off-sets the overall performance to such an extent as to rule out certain speakers?

Gents, I think we can summon up the above posts with this: It is extremely important to acquire a speaker that has a good synergy with the amp that powers it.

@daveyf

You are right about the amp issues regarding hi vs lo efficiency designs, well said. Yes, a low efficiency design might require more power.  But these issues are truely complex and trying to make a blanket statement that some performance related feature is always good or always bad doesnt really work in audio. People long for universal truths, but in audio, the truth is conditional.

Brad

@daveyf  you also have to consider that tube amps with high sensitivity speakers also limit many tube systems because of noise and hiss which you can't hear as well with low sensitivity speakers. Not all tube equipment is quiet, just like not all high powered amps sound bad.

@lonemountain wrote:

When you say that efficiency is not the most important aspect of performance ...

I wrote it’s "not the only" important aspect. These last ~15 years I’ve avoided low efficiency speakers as anything I’d consider buying (with the exception of seriously considering at one point larger and active ATC models, in particular the SCM150ASL Pro’s (and ultimately the SCM300’s, had economy allowed)), but efficiency as a standalone parameter isn’t as much the true indicator vs. what it leads to design- and size-wise, and so it’s really the other way ’round: the designs I prefer are mostly horn-based and large, and therefore, in effect, high to very high efficiency as well. It’s not that I can’t enjoy the sound of many a low. eff. design, quite to the contrary, but I’m simply pursuing a different route with different strengths sonically compared to what smaller, more inefficient and passively configured speakers can deliver.

I disagree that efficiency is the "preferred route" in achieving lower distortion, improved dynamics or increased bass. There are so many other avenues to these features.

Fair enough, but coming down to it we’ll have to disagree on this one. Yes, there are other avenues and areas of importance here that can make a low eff. package sound indeed very good in named areas, but when higher efficiency enters the "equation" to boot (again, not as the only parameter as anything worth considering) the significance in performance - to my ears and sensibilities - is not trivial.

ATC is a notable exception here, to an extend, in that their engineering prowess in driver development and overall execution is on another level compared to most lower eff. speaker manufacturers (and thus, and this needs to be stressed, they’re hardly representative of the low eff. segment of speakers). Active config. only adds to this advantage. The SCM150 and SCM300ASL Pro’s - that I’ve auditioned quite a few times - are excellent speakers in their own right that I could easily live with, and yet a large horn-based system (not least actively configured) does something else both dynamically, with regard to ease(!), scale, presence, immersively, viscerally and bass delivery that you’ll have to experience to fully understand and appreciate.

I did not say that low eff. designs avoid the limitations of poor efficiency simply by adding more power. There may not be limitations of lower efficiency designs, depending on your goals. Or there could be limitations of a high efficiency design.

Different contexts will have things in variables, yes, but getting a true bearing on a more complete wallop and significance of uninhibited dynamics, low distortion imprinting and smooth, effortless bass prowess at more than moderate SPL’s and shorter listening distances will require setting a different benchmark; to some these very aspects aren’t main priorities, let alone secondary, but to others they’re quite another connoisseur matter and will necessitate measures that goes beyond smaller, passively driven and low efficiency speakers.

I think the whole array of solutions are far more complex than high or low efficiency "spec" on a spec sheet. Whether something is 92dB 1w/1m in a loudspeaker gives you zero information about quality when compared to a 86dB 1w/1m spec.. You only know the designer chose to chase efficiency (probably for more than one reason). Intended application is everything..

Chasing efficiency in itself would seem crude, but let’s make it actual high efficiency to begin with if we really want to refer to it as such; my understanding of high efficiency, all along, has been a sensitivity from 95-100dB’s on up. Few designs really accomplish that, and if you intend to have a fairly uniform and controlled directivity pattern at the vital crossover(s), not least crossing low enough to avoid the central midrange while maintaining sensitivity all the way down low to the 20-30Hz region, then you’ll have yourself a large sized package that can really show its mettle with the parameters referred to earlier.

Some lower efficiency designs can achieve lower distortion in the driver, or can extend low frequency of that driver or both. Or your lower effieciency design may improve cooling and power handling without extending voice coil length. I guess to me its like horsepower tells you zero about the performance of a car. There are so many different options available to a skilled designer that focusing only on a high efficiency design is not wise, again, depending on your goals. I favor lower distortion myself, I want to hear more of the fine details, the reverb tails, the room sound, etc. If I can have lower distortion that reveals more of that fine detail in exchange for a larger power amp, I’m in. That’s the trade off I am talking about. And I’ll stick to my guns on this one, you cannot have it all.

And this is where we are ultimately disagreeing. Within the design differences inherently at play here I do believe we can more or less have it all; care taken with a specific design is not limited to low efficiency dittos, and if you’re willing to go the distance and let size and physics have its say, it means upping the potential of such designs even further. No, I wouldn’t cram speakers that large in small rooms, but contrary to common belief they can be implemented excellently in moderately sized listening spaces - not least actively.

@lonemountain   While I would agree that sensitivity alone is not a indicator of quality or sonic virtue in loudspeakers, it certainly is an indicator as to what one can expect as to choosing an amp that will work well with said speakers. As such, the number and type of amps that will work is now significantly diminished, and as pointed out above by atmasphere, said amp will almost certainly NOT be working at its best. It also pretty much removes certain types of amp designs...mostly in the tubed genre.

@rauliruegas I think we need to be more clear as to what we are discussing when it comes to lower sensitivity. There is little question that a lot of great speakers are in the less efficient camp, meaning that they are not in the 100db/w mode, but closer to 85db/w etc., These very same speakers may drop down into the 3-4 ohm load in the bass, which might present a more challenging load to some amp designs, but like pointed out, with a sufficiently beefy power supply, will still work fine. These are not really the speakers that I am talking about here ( not sure about others), instead the designs that are on the market ( or have been on the market) that drop down to 1 ohm or less, and as such, are now presenting a very difficult load to the upstream amp. There are not too many speakers that this applies to, but you might be surprised by how many it does. Plus, many of these designs are from well known ( and respected) manufacturer’s, like the ones in my OP.

Again

Speaker sensitivty alone is not an indicator of quality or sonic virtue in loudspeakers.  I can think of other values that might be related to sonic virtue, such as widely varying impedance (in a passive design), high distortion, limited dispersion, inconsistent dispersion across the audio band, etc, etc.  High efficiency is simply an engineering choice made, not an evolution.

Brad       

@daveyf  : Yes, maybe me.

@unsound   " speakers designers have to choose what paramters and associated compromises combine to best meet ultimate design goals. Some if not most of the best measuring loudpseakers have lower impedances, and ergo lower sensitivity. There are a bountiful number of well designed amps that can handle such loads with minimal consequence. "

In total agreement with you.

R.

@rauliruegas Which other gentleman are you referring to? I don’t think anyone on this thread is totally wrong…except maybe you, lol😁.

just kidding..😎

Dear @daveyf  : First than all I'm a MUSIC lover and each single week at least I ttend to enjoy Live MUSIC and this " attitude " I have it for the last 25+ years.

I hate to listen the system Hardware and my room/system is builded through several years around nothing less than MUSIC but to enjoy MUSIC in my home we all need some kind of source/hardware.

I used tube electronics over 10+ years till I learned.

My ADS L2030 " old " speakers has 95db efficiency, no there is no single design problem with:

Vintage Holy Grail ADS L2030 High Fidelity Stereo Speakers and ADS C2000 Control Photo #1889387 - Aussie Audio Mart

The other gentleman ixs totally wrong, maybe he need to talk with J.Curl about that design or learn in other way about that specific design. I really don't care on his post that only shows high ignorance in tha specific regards amps.

R.

This has been discussed ad nauseum here on Audiogon. Low impedances can lower sensitivity which can make amps work harder to produce power and increase amp distortions. The degree to which the amp distorts due to this depends on the stoutness of the amp. The greater the loudspeakers sensitivity the more likely it will be a more open gateway to what distortions are still presented by upstream components, including but not limited from the amp. What is often less discussed is that varying impedances can strain amps too, and is more likely to present difficult phase angles to the amp as well. It is far easier to present and maintain a steady impedance by lowering the impedance of loudspeaker than visa versa. Electro-mechanical components are much more difficult to make perform well than purely electrical components. The variance between loudspeakers is typically much greater than between decently designed amps. This might suggest that more leaway be given to loudpspeakers than amps. As has previously (and wisely) suggested here; speakers designers have to choose what paramters and associated compromises combine to best meet ultimate design goals. Some if not most of the best measuring loudpseakers have lower impedances, and ergo lower sensitivity. There are a bountiful number of well designed amps that can handle such loads with minimal consequence.

If a speaker requires an amp/ arc welder up front to drive it, then IMO, there is a problem with the speaker design. YMMV.

Exactly! Such speakers border on criminal as there simply aren't amps that sound like music that can drive them nor would they be all that musical due to thermal compression.

I look at it this way- if you can't drive it well with 100 Watts (in most rooms), its a problem. That is because the ear hears sound pressure on a logarithmic scale. So to get twice as loud (perceptually) that you can get with 100 Watt, you need 10x more- and 1000 Watt amps that sound like music don't seem to exist although class D is getting close with amps that can make 600 Watts or so.

The problem (again) is getting enough Gain Bandwidth Product in the design such that it can support the gain of the amp along with the feedback it has (together, known as 'loop gain'). If not, and this applies to almost all amplifiers ever made prior to about 2000 or so, you get distortion rising with frequency with its attendant unpleasantness- this is a good portion of the reason feedback has gotten a bad rap in high end audio. 

Its not feedback's fault so much as poor execution of feedback.

Plus a 1000 Watt amp would not be able to make up for the thermal compression that would be present- as I mentioned before, as you try to turn it up to get around the problem, it just gets worse. 

@atmasphere   :0)

@rauliruegas  If you are happy with owning an arc welding machine, more power. Personally, I prefer to listen to music, and as such I generally prefer the lower powered amps, most particularly of the tube variety. I am in 100% agreement with what @atmasphere stated above. 

If a speaker requires an amp/ arc welder up front to drive it, then IMO, there is a problem with the speaker design. YMMV.

Dear @daveyf   .: You are rigth and I was lucky enough to found out all the power supply, protection circuit, input electrical circuit electrolithics at its original values through the best of the best caps: Vishay.

When I did it ( less than 2 years ago ) and I listened again what I listened was and is nothing less than stunnig for say the least. I bougth my 20.6 second hand and I did it to been paired with a pair of 20.5s that I owned too in a bi-amp configuration and latter on that I learned I sold the 20.5s

" The amplifier performed beautifully, showing maximum distortion of 0.42% THD + N at 20 kHz. This distortion level would not be audible on music and is comparable to published ratings for high - quality tube amps driving standard loads; here, we were using one-fourth of the amplifier's minimum rated load! "

 but in that 20's monoblocks review ( not the 20.6 that are even better ) that  THD does noit changes even at 1 ohm where the 20's  shoiwed 800 watts. Even those reviewers made this experiment with the monobloks:

"" An enthusiastic reviewer might call a beefy amplifier an "arc welder" as an exaggerated compliment to its ruggedness and current -handling capacity. However, no one would really expect an amplifier to actually melt steel. Almost no one, that is, except this reviewing team. We say this amplifier is an arc welder and back up this statement with a photograph (Fig. B1) of two 0.05 -inch steel plates welded together by a pair of Mark Levinson No. 20s. Arc welding is accomplished by creating an electric arc that melts metal. The molten sections of the items to be joined flow together and are then allowed to cool. In practice, the power source is connected to the two pieces to be joined and to a flux - coated welding rod. The arc is struck by momentarily shorting the rod to the work pieces. The flux is vaporized, forming an ionic conducting path for the arc and cleaning the metal. The arc stabilizes at about 100 amperes and 30 V (creating temperatures of 3,000° F), depending on the thickness of the metal and welding rod. If this sounds like the world's worst amplifier load, you're right! Coauthor Clark summoned Paul Grzebik to carry out the task. Paul has the reputation, in Detroit's technical community, for a willingness to try anything once, from building a parade float to scaling a TV transmitting tower. He readily agreed to our assignment. Clark drove both No. 20 amps with a 1 -kHz square wave to full output into a series resistor mixing network that combined both amplifier Fig. B1-Results of the arc -welding experiment. outputs in parallel to obtain the high current needed. After experimentation (and several blown line fuses), approximately 1 ohm was found to deliver the maximum current for starting and sustaining the arc. Wearing a mask and gloves (the intense blue light from the arc can burn the unprotected retina, while molten metal can splatter on the hands), Grzebik began welding. The arc turned out to be a fairly effective plasma tweeter, creating strong 1 - kHz square -wave sound radiation that required wearing ear protectors as well. Grzebik completed a small weld and, impressed, pronounced it satisfactory. After the welding, the No. 20s, still only lukewarm, were again put on the test bench. Distortion tests verified that no change in their performance had resulted from this extraordinary exercise. What's the point? With this test, Clark verified his confidence in the exceptional output capability and comprehensive protection built into these amplifiers. A few other amps might be able to weld steel without destroying themselves, but the No. 20s were certain to survive the experiment. One note: Don't attempt this feat yourself unless you are an accomplished welder, have the proper equipment, and are using amplifiers with extraordinary protection circuitry and output stages that can handle current extremes. Injury to yourself and destruction of lesser amplifiers may result. Don't expect manufacturers to repair your damaged amp under warranty, either! "

So,  we don't have to care on what  that tube manufacturer posted because it does not happens exactly as that. The very old 20's proved that and that design comes from 1986.

As always, there are designers and designers and J.Curl is really good . Remember the Vendetta Research phono stage? came from J.Curl and several other electronics designs as the Parasound and the like.

R.

 I suggest since you are such a big fan of the Parasound JC1+'s sound that you go out and immediately buy a pair, if you haven't already...That's what I am talking about...;0)

@daveyf :)

Distortion vs frequency is a better measure of how musical the amp might be. It must not rise in the audio band else higher ordered harmonics can become more audible than THD values (usually measured at a pretty low frequency) would suggest. You can see this is a problem with the JC1. This is caused by a low Gain Bandwidth Product value, where the feedback ceases to be supported at a certain frequency and so decreases, initially at 6dB/octave. Distortion thus rises on a complementary curve. This is a very important reason why do many solid state amps of the past have sounded bright and harsh- its literally what has kept tubes in business the last 6 decades.

@rauliruegas   Presumably by now you have replaced the caps in those ML 20.6's?? Yes?

Dear @daveyf  : I know and listened sevral times in different home top room/systems the original JC 1 and the JC 1+ too.

But, I don't need to buy it because my Levinson 20.6 monoblocks was and till today it's the J.Curl Statement Design. Yes better than the JC 1+ and better that many today $$$$ SS monobloks and guess what: the 20,6 are pure Class A and doubles its power down to 0.5 ohms. It's a true beauty of design and it's a learning electronics for any SS amps designers.

That's what I'm talking about.

R.

@rauliruegas   I suggest since you are such a big fan of the Parasound JC1+'s sound that you go out and immediately buy a pair, if you haven't already...That's what I am talking about...;0)

@daveyf  : As many others including what posted that gentleman ceratinly did not read yet te JC 1+ review that between other things states:

" 

The JC 1+'s shielded input- and driver-stage circuit boards use an FR408 substrate, a substance that was developed for ultra-high-speed applications in supercomputers and aerospace.

• As in the JC 1, the JC 1+ input stage uses hand-matched pairs (footnote 2) of Toshiba 2SJ74 P-channel and 2SK170 N-channel J-FETs. Parasound and, I believe, Ayre Acoustics have invested heavily to secure an ample stock of these no-longer-manufactured, low-noise J-FETs. While the JC 1 driver was a single-stage circuit, for the JC 1+, John Curl designed a two-stage, cascode driver that would have some of the favorable attributes of vacuum tubes.

• As the number of high-performance loudspeakers with impedances that drop below 2 ohms is on the increase, Curl increased the number of Sanken NPN and PNP bipolar output transistors from 18 to 24. The output-stage circuit boards are now mounted vertically rather than horizontally, which should result in more effective heat dissipation. To deal with the increased current, the copper traces on the amplifier's main circuit board and the output-stage circuit boards are twice as thick as on the JC 1.

• The peak output current is specified as 180A, supplied by Nichicon Gold Tune capacitors, two more than the JC 1. Richard Schram says that although the Gold Tune capacitors were discontinued years ago, Nichicon continues to manufacture them exclusively for Parasound. "

Peak current : 180A. So what are you talking about? J.Curl does not makes that kind of mistakes.

R.

@rauliruegas While the speakers in my OP were indeed not the same as the ones in my example with the Parasounds, the speakers in the OP were in the same category ( and actually the same maker) as the ones in my example. I suspect that the Parasounds ( like most amps, and as Atmasphere pointed out above) would not be working at their best with such a load.

Dear @daveyf  : About the JC 1+ I was refering to the speakers in demo by the seller in your OP and not about the owner of those Parasound amps that btw can handled with out problem to high SPL that 1 ohm impedance.

R.

@deep_333 LOL, there are a number of well respected speakers that drop down to 1ohm. I won’t consider them for purchase; but I suspect that most folks will not label their designers...’lazy low IQ individuals’! The speakers I was listening to in my OP come from a well known designer who has had several ’amp busting’ speakers on the market in the past.

Keeping in mind that the speakers in question drop down to around 1ohm in the bass, resulting in a speaker that very few amps can drive to anything that can bring about their best. 

Any speaker that drops to 1 ohm was designed by a lazy low IQ individual. Such a speaker (his low IQ legacy) should be torn down and thrown in the garbage can.

@rauliruegas I cannot comment too much on the sound of the Parasounds and the speaker at this fellow’s room. I heard the combo briefly, but do remember thinking that the synergy was not there between the components.

Keeping in mind that the speakers in question drop down to around 1ohm in the bass, resulting in a speaker that very few amps can drive to anything that can bring about their best. Nonetheless, the Parasounds were not an amp that resulted in this fellow being impressed with the combo.

Noise/distortion --> the room and the speakers trump whatever anyone’s attributing to any decent amp.

It’s like you’re having your carriage pulled by a dying horse, but you’re dead focused on greasing the wheels with some special oil secreted on a blue moon night.

Dear @daveyf : The issue thatan amplifier working harder develops higher distortions could not be exactly as was posted.

You can read in the link that the JC 1+ gives you at full power output same distortion levels at 8ohm, 4ohm and 2ohms: 0.15%.

The other issue about is that the levl of distortions each one of us can detect it as an added colorations depends on what the brain amygdala whole audio/MUSIC information is hang on to for the life experiences of different kind of sound and different kind of SPLs.

J.Curl knows exactly how design  "  a huge ss amp upstream ".

Speaker efficiency always is important depending how you paired with the rigth amp in the rigth room and of course inside your MUSIC reproduction priorities or restrictions. 

Now and is something that you don't touched yet other than " good sounding " and you did not tell us with wich electronics ( overall ) you were listened, with which MUSIC sources and MUSIC gender and at which SPLs.

R.

@phusis

Nicely written! I enjoy your perspective. When you say that efficiency is not the most important aspect of performance, you and I are on the same page. I disagree that efficiency is the "preferred route" in achieving lower distortion, improved dynamics or increased bass. There are so many other avenues to these features.

I did not say that low eff. designs avoid the limitations of poor efficiency simply by adding more power. There may not be limitations of lower efficiency designs, depending on your goals. Or there could be limitations of a high efficiency design. I think the whole array of solutions are far more complex than high or low efficiency "spec" on a spec sheet. Whether something is 92dB 1w/1m in a loudspeaker gives you zero information about quality when compared to a 86dB 1w/1m spec.. You only know the designer chose to chase efficiency (probably for more than one reason). Intended application is everything..

Some lower efficiency designs can achieve lower distortion in the driver, or can extend low frequency of that driver or both. Or your lower effieciency design may improve cooling and power handling without extending voice coil length. I guess to me its like horsepower tells you zero about the performance of a car. There are so many different options available to a skilled designer that focusing only on a high efficiency design is not wise, again, depending on your goals. I favor lower distortion myself, I want to hear more of the fine details, the reverb tails, the room sound, etc. If I can have lower distortion that reveals more of that fine detail in exchange for a larger power amp, I’m in.  That's the trade off I am talking about.  And I'll stick to my guns on this one, you cannot have it all.  

Brad

.

@lonemountain --

The question is, certainly to me, what we’re actually disagreeing on here. My remarks above were aimed specifically at the parameters brought up by you, namely distortion, dynamic range and "better bass," and I’ll maintain that higher efficiency is the preferred route for these parameters to be better realized. While many understand high efficiency to be mainly about achieving higher SPL’s, to me it’s about what these designs offer sonically as a consequence of their higher eff., and that it translates at moderate SPL’s as well.

Decide what you want, then figure out what speakers do that.

To me it’s really the other way ’round; observation and discovery (and this is where open mindedness is truly challenged) ultimately points me in a direction of speakers and overall implementation, stuff I could hardly imagine or have come by if it weren’t for experimentation or even chance. It’s a process where preconceptions are readily confronted.

As to my clarification on efficiency, it exposes how many audiophiles tend to exaggerate the efficiency of speakers with a sensitivity range somewhere between the typical 80-90dB’s. Why, or how is that relevant? Because as poster @atmasphere and ​​​​@ditusa point to you don’t just compensate freely for low efficiency with more power, not even in a home setting, and this goes for both speakers and amps.

Efficiency is just one of these many features.

Sure, but for my own part I’ve never claimed it’s the only important aspect (though a vital one). Rather it often comes down to defending high efficiency in the face of the opposing view that low eff. designs can avoid the limitations of poor efficiency simply by adding more power, and thus, implicitly, are having the "fuller package" by comparison. I absolutely disagree with that.

@atmasphere wrote:

Unless you can. I have a set of Classic Audio Loudspeakers (model T-3.3) which are some of the most revealing speakers I’ve heard, even compared to the best ESLs. They are flat to 20Hz, are 98dB, field coil powered and 16 Ohms. So fast, revealing, full bandwidth and actually work quite nicely in a smaller room since you can back them up against the wall behind them without making them boomy or losing any sound stage palpability. Put another way I don’t know of a speaker at any price that works better, although its probably out there.

They are not cheap; IMO your comment would be more accurate if price were part of the equation.

I’d add it’s not limited by price as much as mere physics and overall execution/implementation.

The physics of the speaker is a balancing act: if you want more efficiency you give up other advantages. Im not saying this is wrong, it’s simply a choice. A moderate efficiency speaker (86dB 1w/1m) is not a mistake either as it is just a different choice that enables other performance features that high efficiency cannot offer. You cannot have it all.

@lonemountain Unless you can. I have a set of Classic Audio Loudspeakers (model T-3.3) which are some of the most revealing speakers I've heard, even compared to the best ESLs. They are flat to 20Hz, are 98dB, field coil powered and 16 Ohms. So fast, revealing, full bandwidth and actually work quite nicely in a smaller room since you can back them up against the wall behind them without making them boomy or losing any sound stage palpability. Put another way I don't know of a speaker at any price that works better, although its probably out there. 

They are not cheap; IMO your comment would be more accurate if price were part of the equation.

@atmasphere +1 I couldn't agree more!

Mike

@rauliruegas Funny you bring up the Parasound amps. A fellow a'phile whom I know well, decided to buy a pair of very expensive and very difficult to drive speakers, reasoning like you, that the Parasounds would be the answer. His budget was limited a little, so he spent the $$ on the speakers and left himself with only one option for the amps...based on his budget. Let's just say that the speakers went onto the used market within a few months, and he was forced to sell them at a considerable loss. I believe what @atmasphere noted above is the whole reason.

PS. He no longer owns the Parasounds either.

Dear @daveyf  : IN any case and not so expensive you can find out the  Parasound JC 1+ monoblocks that when you listen it in any speaker at any SPL you did not ask if you are listening tube or SS amp but only enjoying MUSIC.

John Curl is a very low profile Master Designer Electronics Engineer.

Parasound Halo JC 1+ monoblock power amplifier | Stereophile.com

Regards and enjoy the MUSIC NOT DISTORTIONS,

@lonemountain +1.

@atmasphere   Thank you. If you would have told the dealer exactly what you posted, he would have belittled you just the same. Some folk have agendas, and in this case, the guy was only interested in selling this speaker....not in discussing in any way the potential downfalls that this design elicits. OTOH, that was his job that day.

@lonemountain I couldn't agree with you more, it is absolutely important that one match their desired speaker to the space/room that it is going to be listened to in. However, the efficiency and the very nasty load that the speaker in question presents to the amp is a factor that IMO should not be overlooked, regardless of the room size. Personally, i am not that concerned about speakers that present a moderate efficiency, only those ( like the design in question, and others) that present basically a short to the upstream amp! 

@phusis

I normally agree with your posts, but not this one. A transducer engineer like Doug Button (he worked at EV when I did, and then again at JBL when I was there) or Rich at ATC would agree with my post (maybe not exactly the way I say it). The physics of the speaker is a balancing act: if you want more efficiency you give up other advantages. Im not saying this is wrong, it’s simply a choice. A moderate efficiency speaker (86dB 1w/1m) is not a mistake either as it is just a different choice that enables other performance features that high efficiency cannot offer. You cannot have it all. My point is simply that this thread seems to universally promote that high efficiency is the primary hallmark of high performance and that is simply not true. It can be important if you need High SPL, or like horns or big wave-guides (which can image well), or use speakers in a highly reverberant environment where narrow dispersion is an advantage, but these conditions certainly don’t exist in every room or for every listener. It’s a trade off and is not a "good or bad" or "right and wrong" thing. Decide what you want, then figure out what speakers do that.

A good example of deciding what’s important to you is a listener in a small space; a small stand mount speaker with excellent low frequency output, say a LS3/5a type KEF design would be a good choice. Super high efficiency is not gonna happen in this type of design. If a listener wants wide dispersion speaker because he/she wants it to sound the same anywhere in front of the speaker, super high efficiency is not gonna happen. If a listener wants super low distortion because they are in mastering or recording, then super high efficiency is typically not a goal. The hardest part may be understanding what you want in your space vs what other people want in their space, as the reviews say this is good or bad but don’t really discuss the space or the listeners goals much. Whether it’s good or bad is ALL about matching your space and your goals with a speaker. High end speakers are not good or bad on some universal scale. There are too many engineering goals/design features to account for that define good or bad in a given space. Efficiency is just one of these many features.

Brad

Problem is that they also require a very large ss amp upstream to drive them. Something that can push a lot of current, which pretty much rules out most low-mid ( maybe even high) powered tube amps. When I mentioned this to the person doing the demo, i was basically belittled, as he felt that the efficiency of a speaker is pretty much irrelevant ( well he would, as he is trying to sell these speakers). The speaker line is fairly well known to drop down to a very low impedance level in the bass regions. This requires an amp that is going to be $$$, as it has to not be bothered by the lowest impedances.

Low impedance and low efficiency is a bad combination if you want the best out of your amplifier, regardless of the amplifier type.

@ditusa has put his finger on a serious problem with lower efficiency speakers, one that isn't overcome by higher amplifier power, in fact makes it worse.

But you also have the problem of distortion from the amp. With any amplifier, the harder it has to work the more distortion it will make. So 4 Ohm distortion is always going to be higher than 8 Ohm distortion. You might think that small increase isn't audible but that would be ignoring how the ear perceives sound and in particular, tone color and sound pressure.

Sound pressure is perceived through the higher ordered harmonics, If you increase them by even tiny amounts its audible as greater loudness (BTW this is easy to demonstrate through simple test equipment).

Distortion modifies the tone color of instruments by adding harmonics. IOW the ear perceives harmonics as a tonality. So adding even a slight amount of distortion will color the sound and very likely in the direction of 'harsher' and 'brighter'.

Put yet another way, if a speaker could be made to be 8 Ohms instead of 4 without changing anything else, the perception would be that the speaker became smoother and more detailed simply because any amplifier driving it would have less distortion.

So efficiency and impedance are both important!!

@lonemountain wrote:

... If you are more open minded and are wiling to look at moderate efficiency speakers in the mid 80s, using the wide array of excellent high power amplifiers available, or active speaker configurations, you can have your low distortion, wide dynamic range AND better bass AND wider dispersion, etc, etc. But you cannot have all that AND super high efficiency.

Sorry, but the above makes little sense to me. 

If by "mid 80s" you mean sensitivity in dB's, then it's a very low efficiency design (i.e.: ~0.2%) and not "moderate" by any means. 105dB's sensitivity on the other hand translates to 20% efficiency, which is very efficient. 

Contrary to your views I find efficient speaker designs - say, from 95-100dB's on up - to be the best way to achieve the combination of low distortion, wide dynamic range AND better bass, with the proviso that the latter requires large size to achieve a fairly deep extension, but that's not a design deficit nor a sonic impediment. And, if I'm to understand you correct, wide dispersion isn't a trait, but a characteristic; if anything a narrow and fairly uniform dispersive nature has advantages over a wide and likely uneven ditto. 

Finally, high efficiency speaker designs can as well and advantageously be run actively. In fact I find that's where they really shine.

Heat Dissipation and Power Compression in Loudspeakers:

If you want the peaks to be at realistic levels, yeah, 150 watts is probably about right to get you to about 107 dB or maybe only a bit over 100 dB when you consider thermal compression.