How important is the efficiency of a speaker to you?

I went to an audio meeting recently and heard a couple of good sounding speakers. These speakers were not inexpensive and were well built. 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.

Personally, if I cannot make a speaker work with most tube amps on the market, or am forced to dig deeply into the pocketbook to own a huge ss amp upstream, this is a MAJOR negative to me with regards to the speaker in question ( whichever speaker that may be). So much so, that I will not entertain this design, regardless of SQ.

Your thoughts?

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The very good high efficiency speakers also require a serious amp, they can still be difficult loads. Flea watt amps are dumb for any kind of speaker, high efficiency or not. Nothing about the flea watt amp guarantees that it is the best design for the first watt or fractions of it. In fact, a lot of them are garbage.

I benefit from speakers being quiet when on standby so I'd stay away from very efficient ones. Need to be between middle and low for that matter. Impedance stability is somewhat more important than efficiency especially If I want to use tube amp. For me performance matters and if I can figure out how to make it sound best, it means the speaker gets my attention for what it's worth. Ima garage sale junkie rat sneaking for lonely grammas to sell audio for cheap so spending not much either. If I note GOOD DEAL from any of the situations I'm trying to take advantage from, I wouldn't really care about neither efficiency nor impedance stability.

A little off subject, but still might pertain. I drive big ss monos and noticed when the speakers were pretty close they seemed to start to cancel each other out. Maybe think spacing and sort of a sound hall, like the opposite of a bass trap. Can’t remember but bose may hsve had engineering that semi included something similar, not positve. Hard to remeber 25 years ago. Lol you might also be able to compromise and look for a/b systems.

I'll admit I'm old and my ability to hear high frequencies has diminished but from the listening position high efficient speakers when driven by a well grounded and well designed amp solid state or tube are dead silent. By pressing your ear against the front of the speaker it is possible that a faint hiss may or not  be heard that's not really an issue as I don't listen that way. 

Flea watt amps are anything but dumb. Low watt amps and high efficiency speakers are about transient speed.


I use high efficiency speakers with high power. Amps have come a long way and high power does not mean bad/noisy anymore.

there is something about dynamics of high efficiency speaker but a lot of things are at play here too. Dispersion of the speaker and load (ohms) also come into play.

Usually low efficiency means complex crossovers. The issues of cross interference, phase coherence and latency resulting from multiple transducers compaerd to a two way, ideally point source in my mind are too complex to solve. That’s why flea amps with high efficiency speakers have such a strong following among true audiophiles

I'm happy with my bi-amped system which combines an efficient dipole line array (98db/w) driven by a DHT SET, and a dipole servo woofer tower handling the lower few octaves and driven by an 800w class D amp. This is the best of both worlds for me. Fast, tight, powerful bass and gorgeous, spacious mids and highs. 

When discussing speakers that are hard to drive, I'm not really talking about speakers that cannot be driven by just a few watts. The video above, with the Decware amp is interesting, because while this amp probably sounds good within its envelope, at just 2.3 watts/ch, it clearly is extremely limited as to what speakers it will work with. This is basically the other end of the scale, the speakers in my OP need a minimum of 100 watts/ch and an amp that can push current into a very low load. The opposite is the case with a tube amp that puts out flea power...this amp can only be matched with a very small number of speakers. ( Relatively). 

So, while I would agree that the cost to put together a system with a flea watt amp is probably less than one that needs a brute of a ss amp upstream, neither is great IMO. 

I am currently using that same 2.3 wpc amp with my 96dB 140 lb floorstanders.  I feed the amp with a Grimm MU1 streamer and a Lampizator Golden Gate 3 DAC.  Interestingly, my DAC uses large DHT tubes capable of making twice the power of the amp (although they don't, the DAC output is line level with volume control).



I like tube amps and generally don't like high powered tube amps so I look for sensitivity in speakers my current AN-J's are 93db and work well on 3.5 2a3 watts. 😉


I too generally prefer low-powered tube amps.  That makes high efficiency and easy load important qualities of a speaker.  AN-J’s are not very high in efficiency, but they are intended to be placed in the corner of a room, which boosts the level of bass and makes them effectively more efficient, and they present an easy load to the amplifier.  I heard crazy-good sound from AN-J SECs driven by a Kageki amp (parallel 2a3 SET amp); an incredibly good match even though the Kageki is something like a 6.5 wpc amp.



this seems like simply a venting thread as nothing is going to change- inefficient speakers require more power than efficient speakers. 

Gan and Purifi based Class D amps will drive any inefficient speakers and the cost is not excessive. I used a Purifi Class D rated at 300wpc to drive ML Vantage speakers which go as low as 1 ohm at times.

It all depends how you want your personal system to sound to you.

Each of us has their own specific criteria and system.

Took me 25 years to appreciate 4 ohm, 92 dB sensitivity speakers with an all vacuum tube preamp and vacuum tube amp (70 watts output).  If you want/like 8 ohm 86 dB sensitivity speakers you will most likely have to go with a high watt output solid state amp (>150 watts).  Which is fine!  I've had both type of systems but prefer the vacuum tube amps and efficient speakers.... The main problem is it takes so long and so much money to finally figure out what you really like.

@kennyc  Well if you think that, there is no further need for you to post on this thread.

@quincy  There is another factor, a high powered good sounding ss amp, particularly one that can push current into very low impedances, is also going to cost a lot more ( on average) than a good sounding medium ( maybe even high powered) powered tube amp.

@mazian   Class D amps are certainly a lower priced option, but most folks still are not that impressed with the SQ. 

Very high efficiency means one can swim in the calm, warm 300B waters, which I love.  Low efficiency means one can swim and surf with the wide variety SS offer, which I also love.  Why choose when you can have both?

Class D amps are certainly a lower priced option, but most folks still are not that impressed with the SQ. 

Most folks not impressed?   Say what?

The most important thing to me is the sound quality of the speakers. They set the stage for what you are going to hear. That is it, no consideration of efficiency. Then I find the proper amplification to support them.

After a love affair with electrostatic and ribbon speakers for decades… which I supported with 150+ pound, massive high powered amps. I realized I really wanted natural / musical sounding system. So I found Sonus Faber speakers, which are mostly 90db efficient and them I found the best sounding amp to support them… so the wpc went from 350 to 70.

Class D has come a long way and I have been more than happy with SQ of the Nord Purifi. Many other reviewers and actual users have also been impressed with most of the new Gan and Class D amps. 

@ghdprentice  I too have moved on from the MLs, now in my 2nd system, and have replaced them with Sonus Fabers. However I have them in biamp mode and am still using the Class D for the bass and a tube amp for the mids and highs.

Planars just sound more realistic to my ears. If they need power, so be it.

I think amps sound better in their their optimum power range instead of a very powerful amp barely putting out even a small fraction of its power...learned that decades ago from guitar amps. I like an efficient speaker with an amp that's digging in a little, like my Heresy IIIs and one of two amps I use with them: A Dennis Had Firebottle SEP or a Pass XA-25. Works for me. It seems that a very high percentage of speakers are in the 89 or less DB range requiring at least my Had amp to stay away except at low levels. A shame. Give me some clear horns over any "conventional drivers in a box," except for nearfield recording monitors.

Dig deep? My Arion Audio S500 amp was priced at $2500 when I got it a few years ago. It packs 500 watts per channel and sound great. My inefficient speakers soak up those watts and sound wonderful to my ears.

Sorry you were belittled, but I think every manufacturer has to find their niche. 

I think that the truth of modern speaker building, especially 2-way systems is that they often give up efficiency for bass output, so I don't really think we can make the case that most speakers should be able to be driven by modest amps.  However, there's a big gap in "normal" 2 way speaker efficiency and say something like the Kef Ref 1 Meta (or whatever it's called) which is technically a 3-way with just amazingly bad impedance curves.

Your average 2-way is not that bad and a modest (50 wpc) tube amp will do well with it.

If you want a 2-way with excellent bass and very tube friendly look at Fritz.  Really excellent.

I just posted this elsewhere

I advise working very hard to find efficient speakers you love, they are out there. Don't even listen to inefficient ones.

That will keep the needed power down: less: cost/size/weight/heat and it will increase placement options of amps, especially integrated with a need to receive signal from a remote.

Importantly, low power needs allows a much easier way to try tubes.

More competition exists at lower power needs, thus more competitive prices, and more used choices.


I have main-system speakers of 89bd/4ohms, 91db/4ohms, and 102db/8ohms. They match up with main amps of 100w Class A SS, 65w PP tube Class A, 8w SET, respectively. Each time I swap in a new combo, it’s my favorite. Many roads to Dublin.

My point of view is that it is a challenge to find speakers that perfectly match your specific sound quality values. It gets much harder by restricting yourself to a subset of speakers. 

@ghdprentice   I agree with this. Not only do you restrict yourself to a subset of speakers, but in the worst case examples, you also restrict yourself to a subset of amps. Like many of us, i know of a few a'philes who bought their dream speaker, only to find that the amp(s) required were a deal breaker, not only from a budget perspective, but also in many cases, from a placement/heat/aesthetics/weight perspective as well.

More Efficient just means louder. Alone it has little to do with what amps will drive the speakers well ie produce the intended sound completely. That has more to do with how difficult a load which is more about impedance, not efficiency.

So really all more efficient means is a flea powered tube amp can make them go louder before clipping sets in. It does not mean one is getting all they can out of the speakers regardless of amp. That’s not to say the results will necessarily sound bad, just not optimal, and different with different amps, not the same


Take Fritz speakers as an example. If you check out the website you find these are designed to be an easy load for any amp but are not high efficiency. They will sound more similarly good off most any amp and still achieve decent SPL with most any amp, so they are an excellent choice for someone who wants to get best end results using most any amp. The site also shows how the Fritz speakers compare In this regard to other popular speakers. 

Efficient also means the drivers don't have to work as hard to make music...It's been scientifically proven that efficient drivers are happier. Also factually true is a 500 watt or so amp into efficient speakers might be using 1% of its mojo. And yes, the correct term here is "mojo."

My thinking is that efficiency is a product of both reactance (impedance and phase angle) and sensitivity. The reactance relates most toward 'easy to drive' while sensitivity relates more toward size of room to be pressurized. 

Since the Fritz speaker has been mentioned, I will add that Fritz speakers are easy to drive having a benign reactivity. A sensitivity around 88-90dB allows them to be played in smaller rooms with low wattage amps. As room size increases power requirement also increases however I can't imagine anyone needing more than 100wpc to drive them to their maximun output. If one is playing them that loud their room size/listening level likely is better suited toward a larger speaker.

I prefer speakers with a sensitivity range between 86-88 dB; I dislike those with a sensitivity higher than 88 dB because I want to avoid any hiss from the speakers. Contrary to the belief that high-sensitivity speakers perform better in low-level listening, the key lies in how you adjust the equalization to achieve a proper ELC.

Another misconception is that people believe high-sensitivity speakers can be driven by lower-wattage amplification and produce equally good, if not better, sound quality. There are a couple of reviews demonstrating that the Klipsch Cornwall IV (102 dB) can be driven with a higher-power amplifier to achieve better sound quality with more control throughout the frequency range than lower-power counterparts.

I went from 87 db speakers to 94 db speakers. Much better sound at low volume and less power needed.

@daveyf Wrote:

 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 

The importance of speaker efficiency: The article below is from 1962 and is as relevant today as it was then. In my opinion, a high powered amplifier that can drive lower impedances will never be a proxy for a speaker's lack of true efficiency. 



A high efficiency speaker takes less watts to drive to the same volume level as a lower efficiency speaker.

ALL OTHER THINGS BEING EQUAL... If a speaker is 10 dB louder than the other, it takes 1/10th the power to drive to the same volume level.

The amplifier takes time to make this power (i.e., slew rate). So the amp "slews" 3.16 times faster to reach the same volume level resulting in increased dynamics for the high efficiency speaker.

@daveyf wrote:


How important is the efficiency of a speaker to you?

In effect: a lot. Comparing speakers of different efficiencies isn't an apples to apples scenario. With either "camp" there are implications with regard to the nature of directivity (and -uniformity), driver and enclosure size, driver type/segment and other, which in turn has sonic consequences. My eventually veering towards the high efficiency segment of (large) speakers wasn't due to some blind rationale of attaining high efficiency (and SPL) in itself, but rather what those speakers offer in vital parameters of sound reproduction that separates them from the low efficiency segment of speakers here, also with regard to the interaction with acoustics. 

With passively configured, low efficiency speakers it was very much about finding that particular speaker which had the desired characteristics in a given listening space. Not an easy task. With DSP-based and larger, high eff. speakers that are outboard actively configured it's more about getting the basic physics and design execution in place as a framework to go by, call them macro parameters, and then slowly work your way in from that outset to get to where it all gels. 

The worst outset dynamically are small, passively configured, low efficiency, low impedance and load-heavy speakers, although it's the bigger multiway iterations that'll more readily get the amp(s) to their knees. Even served a ton of watts such speakers never escape the fact they're the sonic equivalent of a liquid-saturated sponge that never truly lifts off and comes to life.

Getting rid of a complex passive crossover is a good start, and then higher efficiency will be a further improvement - certainly dynamically. Amp-wise I'm not really the SET-guy (although they can sound great through very high eff. horn speakers), but I like class A/B studio designs which in my case are high powered (~600W/8 ohm per stereo amp, three of them) and of the same brand and series. They're essentially similar top to bottom, incl. the subs, and it pays off sonically. To those squinting at the high power rating here, remember it comes down to how it sounds..

What many seem to forget is that bi-amping actively will have each amp delivered its limited frequency span to feed its respective driver segment (as opposed to passively where they receive the full signal). So, the amp unloading power into the subs won't affect the other amps at all, the HF-amp is relieved of LF, etc. - with all that implies.

No power draining, complex passive crossovers; high efficiency, large and sufficiently tall speakers (i.e.: 97 (plus corner load) to 111dB sensitivity); plenty of power from independently configured amps, not too heavily damped acoustics - to me this is all about efficiency, less energy store-up and achieving proper headroom. Not as parameters standing on their own, but an essential outset to build on. 

Flea watt amps are anything but dumb. Low watt amps and high efficiency speakers are about transient speed.

Huh?? @danager , what transient speed did you obtain with a flea watt amp paired with the high efficiency speaker that a meatheaded amp couldn’t do (with the same speaker)? Please elaborate. I have nothing against high efficiency speakers. I do have a problem with this flea watt miracle (supposedly). Essentially, they tend to gimp such speakers.


That’s why flea amps with high efficiency speakers have such a strong following among true audiophiles

@antigrunge2 ....Again, no problem with high efficiency speakers. But, ugh, what the hell benefit did you get by pairing it with a flea watt amp?? A "true audiophile" like you knows of some mystery that an "untrue audiophile" like me doesn’t get perhaps?






My comment relates to the high wattage, complex crossover+DSP school of engineering. I have yet to hear a system built that way that offers true timbre and time allignment of its various components. Flea watt amps are not a must but many valve enthusiasts swear by 2A3s.


Here is a white paper written by Steve Deckert that explains it much better than I ever could.

Flea watt amplifiers are class A with minimal circuitry and no negative feedback as opposed to a high powered amplifier that relies on a much more complex circuitry and many more components.  As components are added there is a gain in power but it comes at a cost.  Top of line amplification can minimize those loses with higher quality components and advanced designs but they then become very very expensive and totally unnecessary with a well designed high efficiency speaker.

I'm running corner horns with two watts and can reach 85 to 87db in in a very large space without a sound deficit that's apparent to me.  I'm not able (or want) to play at 110db but I still have bass I can feel in my chest and a detailed sound stage that's simply glorious.






I went from 87 db speakers to 94 db speakers. Much better sound at low volume and less power needed.


I had a similar experience with going from 85 dB sensitivity (84-86 depending on whose numbers one is to believe) Ohm-Walsh 4 speakers to 92-94 dB Klipsch Heresy IV. 

I WAS using an updated (by me) ADCOM GFA-545-II to drive the Ohms (GREAT for RAMMSTEIN!), got into a class AB 6CA7 tube amp - Willsenton R8, totally modified/updated by me - then got the Klipsch speakers and a Tektron TK2 2A3/50I-S amp running 300b tubes.

Just before selling the Ohms, I hooked them up to the class A Tektron and they BARELY sounded like anything but hollow, without presence, a very narrow soundstage, vague, muddy.

I connected the ADCOM amp for the buyer and he was sold on them within seconds of hearing “In Your Eyes.”

I’m using 2A3 tubes now and enjoying 50-60’s Jazz more than ever.

Sensitivity, power driving the right speakers, makes a YUGE difference.



Funny, I can remember a conversation I had with the father of a girl I was dating back around 1974 who said “you only need about 2 watts to listen to music” when the stereo we were playing was something like 50 WPC and after 50 years, I’ve come full-circle to pretty much the same conclusion.



What price  level and brands would you say have overcome the obstacles to achieve top level performance? 

Good to see how many people are getting on the high sensitivity train.  Why do I care?  More users means more choices by manufacturers.  The economics point big manufacturers to the expensive insensitive speakers.  

Some great posts here.

And some denying.


I think a very reasonable argument can be made for low-power amps, along the lines of “the less you mess with the signal, the better.” So assuming you select a well-designed amp, you simply find a speaker that pairs well with it. I have a couple of Pass diy amps with 15 to 25 watts. I’ll call that low power in today’s market. So to go with the 15-watt amp (at 8 ohms) I built speakers with 95db efficiency. Nice sound, really sweet midrange in a 20x20 family room. The 25-watt amp is a little more flexible. It makes 40 watts at 4 ohms. And I like Magnepans, but they’re 86 db and 4 ohms. I tried it and liked it. Volume probably tops out in the low 90s db range in the large room they’re in, but it’s a living room, not my music room, so fine by me. I’ll add that among the high efficiency speakers I have hear at stores and with my local audio group, they have a dynamism I find appealing, really lively. But I value timbre above all, and that usually leads me to Maggies.

High sensitivity speakers w/ true bass extension necessitates large volume cabinets which can mean more $ & potential room / aesthetic placement challenges. That said, as John Atkinson often points out, high sensitivity drivers have substantially less distortion at higher output levels because of the much lower current flowing through their voice coils which generates much less heat & are “ working” much less hard. That said, some may not like the sound of the driver type used to create that high sensitivity ( horns, AMT’s etc). Every method has trade offs.

My own personal preference that to me sounds closest to live music is high sensitivity horns w/ tube amps but not “ flea powered” if you like to listen up loudly in a big room. Very difficult for just about any  lower sensitivity speaker at any price w/ even w/ heroic amplification to match the speed & instant dynamics of a quality horn loaded one. 

Volti Audio Rivals do it for me….


As far at cost to achieve SET sound with power I have no idea.  If you're are really interested you should reach out to somebody like Pat Hickman at Whammerdyne.  He builds both "flea watt" and hi power hybrid amps and I'm sure he could explain both the benefits and drawbacks of the different levels of power.



Not very important. 

The best speakers I have ever heard, and the best I have ever owned (not in the same set, I could not afford the best I've heard), have all not been very efficient.

My old Koss Model 1a full range electrostatic speakers were 87db. But the clarity, detail, attack/decay, soundstage and image they produced are better than pretty much any high efficiency speaker I've heard. 

 I can think of a few exceptions, like the Acapella Audio Arts Hyperion, with their plasma tweeter, and their built in amps for the woofer section.