Millercarbon continues to bleat on about the benefits of high sensitivity speakers in not requiring big amplifier watts. After all, it's true big amplifiers cost big money. If there were no other factors, he would of course be quite right.
So there must be other factors. Why don't all speaker manufacturers build exclusively high sensitivity speakers? In a simple world it ought to be a no-brainer for them to maximise their sales revenue by appealing to a wider market.
But many don't. And in their specs most are prepared to over-estimate the sensitivity of their speakers, by up to 3-4dB in many cases, in order to encourage purchasers. Why do they do it?
There must be a problem. The one that comes to mind is sound quality. It may be that high sensitivity speakers have inherently poorer sound quality than low sensitivity speakers. It may be they are more difficult to engineer for high SQ. There may be aspects of SQ they don't do well.
I've heard the Canterbury and other coaxial Tannoy speakers and liked what I heard. I just did not consider them in the discussion because they I did not consider them to be a single, full-range driver. But, they are certainly great sounding examples of fairly highly efficient speakers that are easy to drive and can be run with low-powered amps. I also agree they are quite nice to look at too.
I have a friend who is now in the process of building a system using the coaxial Altec 604 drivers from Great Plains Audio. At one point, he considered an Onken cabinet, but, the available designs for this driver specify a 360 liter cabinet (one and half times the size of the Canterbury's Onken cabinet) and this was too large to be practical. Too bad, I like the sound of Onken bass reflex speakers.
Thank you nwres, bache, atmasphere for responding to my question.
Which was: If there are such big advantages in high sensitivity speakers why do so many manufacturers build low sensitivity speakers?
Thank you jetter for your kind words.
To miller: I don't want you replying to my posts if you will not answer the question. It helps if you can read and your mind is not closed.
John DeVore's informative and well presented video does not bear on my question at all.
To everyone else: I am not interested in what speakers you like. Nor in how to build a high sensitivity speaker - I just want to know why most aren't doing it. There must be reasons and they are probably technical, or related to cost vs SQ. We are not there yet.
It is about the cost of building/selling/ever decreasing market for large speakers as many have said.
I wouldn’t want to pay for the speakers I luckily inherited, and the typically large house with large listening space they would sound best in.
likewise, I wouldn’t want the challenge of finding small speakers that sound so good I have to have them, nor then have to pay for the additional power they would need.
You made me drag out my drawings for the enclosures I designed, for the drivers I inherited, with the help of Electro-Voice Engineers and my AV Consultant for my current speakers.
Deducting elements within the enclosure, I ended up with net internal volume 6.01 CF
And, responding to my youthful excess, we designed a rear tuned port to squeak out a bit more from the 37 lb 15" woofers. I left the ports open in prior location, ’hear/feel those canons! I closed them when I moved here. Bass is tighter, bass imaging very good, I frequently advise front facing subs located near the mains to achieve imaging of bass. I advise against ports, if any front firing.
They shouldn’t fit here. They are big, this house is a small split level. I got very lucky here, they fit, look, sound great. Whenever we go to other people’s houses, or look inside a house when they are for sale, I always look for where they would go. I see very few houses with a good space for them, even the big Victorian Monsters in the six historic districts of my town.
They are in the background of my ’cleaning LP’s photo’ in my listing on eBay
They are extremely efficient, I could shake the walls with 5 watts probably, I sometimes think about trying my friends 8 wpc amps, but they were driven by 30 wpc mono blocks originally, the amps still work, I have stayed in the 30-35, now 45 wpc size, not too big, not too heavy, not too much heat range. That is the max size tube amp I would want to pay for, or less.
Thanks for inspiring me to look at those old drawings, jogs some great memories.
millercarbon is recommending to exclude all Magnepan speakers as options. In doing so, he is recommending to exclude the best imaging, soundstage, midrange, and treble producing speakers on the market in their price ranges. It's fine that he makes such a recommendation, it doesn't mean anyone should listen to his recommendation or to me, for that matter.
Speakers alone make no sound. Complete systems do. Need to examine the complete system before any meaningful comparison can be made.
My understanding is MC prefers high efficiency speakers because they tend to be easier to drive and will work well with most any amp. There is truth to that. However high efficiency speakers also tend to be large and often expensive. Also bulky and more than many would prefer to have to deal with. That’s why the trend is towards smaller speakers that are necessarily lower efficiency if also extended in the bass. Amp choices for best possible performance are still plentiful but more limited. Many tube amps need not apply.
MC is also a Tekton fan. Tekton does tend to offer larger speakers that are more efficient than most but not as efficient as true "high efficiency" speakers like Klipsch, Avantgarde, Volti, Classic Audio Design, and others. Notice most of those are also large and apply horn/waveguide technology to deliver true high efficiency in something some might want in their homes. Tekton offers good value compared to many for large more efficient than most speakers.
So high efficiency alone can be a good thing but like always no one approach has all the advantages that all will care about most.
Also I gather MCs mindset is real men like large manly speakers that may not be very pretty whereas you are perhaps a bit of a w-ss if you care about aesthetics and how they look in your house. That’s for the wife to care about and the real men to ignore.
At least that is my understanding of how MC thinks, FWIW.
This isn’t an example of my preference but an efficient full range speaker. I guess it would also tick the manly man speaker box as well. I also mentioned the Phantom earlier again not as a preference but what can be done with small enclosures, active crossovers and DSP. I guess these are the opposite.
A low sensitivity speaker can be very bit as dynamic as a high sensitivity speaker. It is just a matter of power. Has anybody ever wondered by no two loudspeakers sound alike? Assuming there is only one accurate sound, that would mean that everyone except for maybe one company has it wrong. More probably nobody has it right. There are so many varied considerations in speaker design that it is difficult to be versed in all of them. So, we are left to art and our own devises, hearing. We all have our theories and preferences which is what makes this fun. I personally don't care at all about efficiency. I separate sub bass from everything else because the considerations are so vastly different. I care about directivity, uniform radiation and radiation type (line vs point source). Because of the directivity mandate I prefer ESL line sources and horns (point source), one moderately inefficient 89-90dB/watt/meter and one very efficient 100+dB/watt/meter. Both are a much better impedance match to air thus the transfer of sound from the driver to air has inherently less distortion. Dynamic drivers sound rounded off to me as if the tips of the transients are missing (no idea if this is correct or not). Many like that "smoothness" and certainly prefer the size. For many it has been the only type they have been exposed to. ESL line source speakers are a bit tricky as they do not conform to the usual rules. Even though they are less efficient, because they project power into the room better than a point source an ESL playing at 90dB at 1 meter will be substantially louder and more dynamic back in the room. Than a dynamic speaker playing at 90dB at 1 meter. Because small ESLs can be rather timid I am of the opinion that if you are going to do ESLs get them 8 or 9 feet tall (depends on your ceiling). It is a major difference in performance, so much so that a pair of subwoofers will never be able to keep up with them, takes at least 4. As for subwoofers, we have been blessed with modern drivers, amps and crossovers. With enough power you can make a subwoofer do almost anything you want within it's volume constraints. The real problem is the room. If you have to you use multiple units and keep the crossover below 80 Hz. With some speakers like planar magnetics and ESLs there are advantages to crossing higher which means placing the subs in a symmetrical array otherwise you can put them anywhere as long as they are up against a wall. If you put a sub in a corner it is going to be louder than the others. Can you make an efficient subwoofer? Sure, I made one, or rather we made two. We put 30" Hartley woofers in 25 cubic foot enclosures and drove each one with 20 class A watts. Ridiculous would be an understatement but it worked. You can not use most modern subwoofer drivers in large enclosures. What happens is the voice coil bottoms out making a very disturbing sound. You could use multiple drivers so that each one sees a smaller volume but you still have a very big speaker. There is this thing now with dipole subwoofers. If you have been mislead to think these work just measure their performance. The data will make you cry. There is no circumstance under which a dipole subwoofer will perform reasonably flat from 18 to 100 Hz. I've never measured the efficiency of one but given the degree of cancelation going on I can't imagine that it will be very good. IMHO full range drivers by themselves do not cut it. You can get a very nice midrange and if you lock your head dead on with the driver some treble and in a transmission line enclosure even a little bass. You can do better with Parts Express, Madisound and a little smarts. Horns are great as they are directional and do not bounce sound all over the place. I love the visual statement some of the systems make. There is nothing cooler than those multicolored and wooden horns. Reminds me of "His Masters Voice" and boy do they go loud. If your thing is pee-watt amplifiers these are definitely your speakers. Good horns will not honk at you like PA speakers and like ESLs the micro-detail and transients are excellent as both are much more efficient at transferring sound to open air. Listen to a drum solo and those snare drum snaps.
OP, you are correct, the John DeVore video does not answer your original question. And for me it is a useful tool to dig deeper into your question. So, why don't manufacturers make efficient speakers? You might want to next ask, how do we determine if a speaker is efficient, what's the difference. And the video helps us understand that some manufacturers are not giving us an honest real world picture with their specs that we can rely on to make that determination. In other words, there are more hard to drive speakers for sale than an arbitrary cut off db number might tell us. I hope you will feel at some point that your question has been answered well enough. And then at some point you may decide you want a new speaker efficient enough to meet your needs. Caveat Emptor, we need to do our homework and not just rely on the published specs.
Has anybody ever wondered by no two loudspeakers sound alike? Assuming there is only one accurate sound, that would mean that everyone except for maybe one company has it wrong.
Sorry but this is completely non sensical...
First "accuracy" is a complex chain of measured numbers, for example in the standard processing of designed pieces of electronic components, but "accuracy" in this sense had "no audible signification" except to certify that a piece of electronic component was rightfully designed....
Then the "accuracy of a sound" is in no way synonymus with the accuracy of an electronic design pieces or the accuracy of the audio system and the accuracy of sound is never reducible to them for his only source and cause...The "accuracy of sound" is a phenomenon mainly linked to the relation between the audio system and his embeddings linked to the ears/brain evalutation...
Then "assuming there is only one accurate sound" is a sentence with absoletely no meaning....And accuracy of a sound in music, is not accuracy in the acoustical sense...Timbre for example is not reducible to tone accuracy only...The accuracy of a sound produced by an electronical design in a laboratory has nothing to do with the accuracy of a sound in a room...
The sound did not come from our speakers to our ears directly in a pure delivery without any noise from any source, but on the contrary is the results of a complex acoustical interaction with the room....More than that the audio system is immersed in the mechanical dimension, in the electrical dimension and in the acoustical dimension, then the sound coming from our speakers is the signal/noise complex chain that is modified by these constraint i called the 3 embeddings....
Then your conclusion is also totally absurd because saying that all companies have it wrong is , like someone who want to recreate the wheel, especially, a non circular wheel....All company have it all relatively right in the limit of the trade-off implicated by electrical and mechanical constraints in the design of speakers and the choices they made...There is no perfect speakers, there is some better than others for some ears and for some goal....
Sound quality, timbre experience, imaging etc all these qualities come from the audio system in his totality embed in a specific room , in a specific house, and in a specific electrical grid..
Someone who think that human experience of musical sound come from the speaker design mainly is beside his shoes...
Why there is no 2 speakers that sound like each other?
The list of reasons is so numerous that reducing it to difference in electronical design and mechanical design of speakers is very misleading...
But in audio thread the electronic design importance veiled for most eyes/ears the importance of the embeddings...
A piece of electronic design cannot work optimally in a non controlled environment.... Is it not simple?
There are so many varied considerations in speaker design that it is difficult to be versed in all of them. So, we are left to art and our own devises, hearing. We all have our theories and preferences which is what makes this fun.
I concur tough with the rest of your post...
Sorry if i seem rude....Anyway you dont read my posts anymore... 😊
At the time Bill Johnson was starting his Audio Research Corporation (1970), his reference loudspeaker was doubled pairs of the KLH 9 Full range ESL (two 9’s per side). High-sensitivity loudspeakers were very available at the time (I heard the ARC SP-2 and D-50 driving a pair of huge bass reflex speakers in ’71), though the new small---and rather insensitive---acoustic suspension designs (pioneered by Acoustic Research with their AR-1 and -3) were quickly becoming the norm. But the sound quality provided by the KLH 9 was preferred to all of them by Johnson (and J. Gordon Holt of Stereophile), this in spite of the fact that the KLH 9 was an extremely insensitive design, and presented an insane load for the power amp (highly capacitive, with a ridiculous impedance profile).
Johnson then heard the new magnetic-planar made by fellow Minnesota resident Jim Winey, the Magneplanar Tympani T-I, and declared that it made the KLH 9 now unlistenable. While the T-I did not possess the high capacitance and impedance characteristics of the KLH, it was even more insensitive. Is there a more power-hungry loudspeaker than Maggies? Once again, Johnson’s reference speaker was an extremely insensitive design. He so liked the Tympani he offered to distribute Magneplanar through his dealer network. Yes, while Maggies present a load to power amps that more sensitive designs don’t, they also create a sound none of them do. The same is true of large full range ESL’s. Pick yer poison!
This is almost exactly what I’m working on, and had hoped to introduce in 2020 but... stuff happened that year...
Anyway I designed a large-format Oblate Spheroid waveguide using Earl Geddes’ equations, like you targeting a 700 Hz crossover to twin 15" midwoofers. That 700 Hz figure is consistent with the findings of David Griesinger which Geddes subscribes to, and is very close to the 800 Hz crossover that Greg Timbers uses in the JBL M2. Imo the ability to cover the spectrum from there on up with a single driver is a major advantage over more "conventional" approaches, in addition to the other advantages of large drivers and high efficiency.
And of course the way around the bass extension/box size/efficiency tradeoff relationship is to hand off the bottom couple of octaves or so to subwoofers.
I’m rather surprised by how similar our approaches are. I knew we were barking up trees in the same forest, but didn’t realize it was the same tree!
That is certainly interesting re: the similarity of approach, and thanks for your added/confirmative info here! Indeed, covering the whole frequency span from ~700Hz on up from a single driver/waveguide/horn element appears to be paramount. The current driver/horn constellation (and soon to be fitted with a bigger horn) of my main speakers sport a 2" exit with a 3" titanium diaphragm, and thus lends great energy and "breathing room" to its lower to central region. This does affect the upper octave however compared to smaller exits of 1 and 1.4" which don't roll off quite as early, though conversely at the expense of lower band energy and higher distortion here. Choices, choices; it's a matter of balance (and preference) with the implementation at hand, but I find it's worth the effort compared to adding another driver element, cross-over and point source.
If I may inquire: what's the intended waveguide exit size of your upcoming design, and would the twin 15" bass/mids be configured D'Appolito style or with both of them below the OS waveguide? Btw, I'm thinking whether Timbers would've preferred a slightly lower cut-off than 800Hz with the M2's, but that the size of its waveguide simply won't allow it? Scaling up the size here likely would've made for a bulkier, and less commercial appearance.
To the OP: sorry for veering off-topic. If nothing else what's elaborated above is an indication of a preference and a desired high eff. design path that seems less popular or visible not for reasons of lack of sonic prowess, but rather size requirements and design principle in particular. Few audiophiles appear interested in compression drivers and horns/waveguides, not to mention larger pro woofer/mids that extends into the central midrange; I'd wager it's largely conjecture aimed at a speaker segment that doesn't speak the conventional hi-fi narrative, and where auditioned their typically denser and more direct/present sounding nature mayn't appeal to those who're usually exposed to a leaner, more laid-back and softer/reverberative presentation.
And may I just add: high efficiency doesn't automatically equate into easy or easier amp load. Less power is stored into heat for a given SPL, but a complex passive x-over here can still drain amps with less prodigious power supplies. For easier an more optimal amp load active configuration is required.
Good post, but I'd have to disagree with below quote:
A low sensitivity speaker can be very bit as dynamic as a high sensitivity speaker. It is just a matter of power.
Sorry, but no. Anything approaching live dynamics calls for both high efficiency and power (with very high eff. all-horn designs less power is needed). It's not only a question of achieving fairly uninhibited SPL's and dynamic envelope, which in itself is no easy task, but doing so with headroom to spare - on the speaker as well as amp side. Indeed, headroom is your friend and aids ease of presentation. Of course, less than live dynamic levels would do for many, but even then (with low eff. speakers) headroom is likely sparse. Power is power, and where less efficiently turned into acoustic output is stored as heat and eventually power compression.
@phusis asked a bunch of good questions. My response:
The round waveguide has a pattern width of 75 degrees and will sit atop the midwoofer box, somewhat reminiscent of some of Avantgarde’s models. So the configuration is "HMM" instead of "MHM". (We heard PBN’s "M2!5" speaker which uses the "HMM" configuration, and even at fairly close range with eyes closed it was coherent.)
Passive crossovers, OTL and SET friendly impedance curves (nothing against active, but my target market is elsewhere). Multiple subwoofers south of 70 Hz or so. Obviously not cheap, but there will be some trickle-down to more affordable models.
* * *
Regarding dynamics:
I'm friends with a recording engineer who, for decades, has been measuring the dynamic compression characteristics of loudspeakers, both home audio and prosound. He has amassed data on over a hundred loudspeakers. He measures the compression of peaks, something that might be called "short-term power compression", as it happens vastly faster than long-term thermal compression. Earl Geddes was the first to bring this up to me, and Floyd Toole exchanged a few messages with me on the subject. He sees it too, and said that it's an area which has not been adequately researched.
Anyway my friend finds a strong correlation between efficiency and freedom from compression on peaks. I'm not going into the specifics because I consider them confidential, as he hopes to publish his findings some day, but in general high efficiency and large-diameter voice coils translate to freedom from compression on peaks.
Thanks for your post mapman and a couple of others on the same point. A large part of the answer to my question seems to be that efficient speakers cost more to build to the same SQ level in part because need to be a lot larger, in part because driver manufacturing tolerances are more critical. This accounts for the huge growth in low-efficiency small box speakers since the 80s.
Just out of school a friend of mine had a pair. Only 10.5 inches high. Great for a student room. Maxim has impressive sound quality for the size and surprising bass if you backed it against a wall.
One might observe that avoiding high amplifier costs with efficient speakers is one side of a coin with high speaker costs on the other side.
Phusis and Duke, I beg to agree and disagree. I have always said the more power the better. This is a relative statement, relative to efficiency and other factors such as the output capability of the speaker. A speaker can only do so loud. I have been listening to as many horn loaded loudspeakers as I can lately and in general they are very impressive or can be very impressive. It is certainly easier to get dynamic sound because they are so efficient and they go very loud. Now an ESLs volume capability is based on its Xmax which is very small in comparison to dynamic speakers. If you try to run it full range with bass laden material it will run out of Xmax pretty quickly and start clipping or rapping the stators. However if you do two things the situation turns upside down. These are, send everything under 100 Hz to a subwoofer array and design the speaker so that it is a full range line source. What you get is every bit as dynamic as a horn system and I think because there are no crossovers otherwise, an effortless naturalness that makes the speakers disappear. Line sources project power better than point sources. Because ESL almost match the impedance of air their transfer of power is very efficient even if their electrical efficiency is not. So, you have a very dynamic, low efficiency speaker system that goes very loud and has no crossovers above 100 Hz. Phusis, lets say you have two speakers that both clip at 120 dB at 1 meter. One has an efficiency of 103 dB/1watt/meter and the other 84dB/1watt/1 meter. With a paltry 2 watts the first is blasting at 106 dB and the second only at 87db. To get the second to 106 dB you need 160 watts and this is at 1 meter. At a reasonable listening distance you are easily under 100db, probably down towards 95 dB. We are not even talking about peaks here. The point is that low efficiency speakers require a lot more power to hit dynamic peaks, hundreds of watts. Duke, your friend has more work to do. There are so many factors involved that I doubt you can make a blanket statement that high efficiency speakers are all more dynamic than low efficiency speakers of various types given appropriate power. It is certainly easier to make high efficiency speakers sound dynamic and I would rather have a good sounding high efficiency loud speaker than an equally good sounding low efficiency speaker. The more power on a relative basis the better. Fortunately for me ESLs are more efficient than ever 89-90dB/1watt/meter and there are plenty of amps now that can drive them without farting or blowing up. I should be able to hit 100 dB without leaving Class A operation.
So what is the term for plain old lack of linearity of a driver? That it's output at 90 dB doesn't match it's output at 70 dB? Is this considered strictly as mechanical compression?
Also, the best AMT's have amazing lack of such artifacts and incredibly robust power handling. :) One of the reason I'm a big fan.
Well, color me surprised, again, that we are comparing insensitive speakers for sound quality. I though this would be about efficiency and how high efficiency drivers, heating up less, were often less prone to thermal compression.
I'm not sure how we can correlate efficiency or sensitivity to sound quality if we are confounding the discussion with types of motors.
A couple of years ago I read an article on compression in traditional dome tweeters. I was 99% sure it was from the late, great Dr.
Siegfried Linkwitz
but now I can't find it.
Anyway, yeah, thermal compression happened supper fast. First tone burst was normal, then by the second only the first couple of cycles were even close to the original output.
Hmm, I recently bought a new set of floor standers that are rated only 2 to 3dB lower efficiency than my existing floor standers. This is in a 5.0 surround setup and the floor standers are used for the front L/R channels. I have a very powerful amp powering the front L/R speakers, which should be able to deliver plenty of power to either of these sets. Now, when watching movies with the new set, it just seems like the sound from the front L/R speakers is a bit anemic compared to the other set.
I did use a sound meter to raise the sound levels in the new set to match my center channel speaker sound level. Thus, both the old speakers and the new ones were set up to match the center speaker level.
"Duke, your friend has more work to do. There are so many factors involved that I doubt you can make a blanket statement that high efficiency speakers are ALL more dynamic than low efficiency speakers of various types given appropriate power. "
I don’t think I made a blanket statement. Here is what I actually wrote:
"My friend finds a STRONG CORRELATION between efficiency and freedom from compression on peaks... IN GENERAL high efficiency and large-diameter voice coils translate to freedom from compression on peaks."
Emphasis mine in both quotes.
In my opinion "strong correlation" and "in general" are not blanket assertions, whereas "all" would have been.
Everything that I’ve ever read about dynamic speakers agrees with Duke’s friend's observations.
Bigger voice coil, more ventilation, lower power dissipation result in lower dynamic compression. Of course, all things are not ever equal, but the difference in engineering speakers for professional, continuous high power use vs. consumer speakers is all out there to read. If you want to maintain high output you must control the heat, weather by reducing power dissipated or increasing ventilation or both.
First, thanks to @b_limo for posting the DeVore video. I hadn’t seen that before and it is the best explanation of the relationship between sensitivity and impedance I’ve ever seen.
Several good answers to the original OP question but I wanted to add my own experience. For some reason I’ve been attracted to the sound of low sensitivity speakers for as long as I’ve had this hobby. It goes back to a pair of Large Advents that I bought in the 70’s after I heard a friends AR speakers. In a trend that has lasted my whole audiophile life, I invested in amplifiers that would drive difficult speakers. After I got my Advents I bought the biggest Marantz receiver they made (2325). Then I upgraded to an Adcom GFA 555.
When I upgraded the Advents in the early 90’s I listened to over a dozen models and I definitely preferred the less sensitive candidates. I settled on a pair of Mirage M3si which have an 87 db sensitivity. Then I upgraded my amp to a Krell KSA 300S. A few years ago I snapped up a pair of Thiel CS6 that a friend had for sale. These speakers driven by my monster Krell make some of the best sound I have ever heard anywhere.
When I went to AXPONA and the Tampa Show in 2018 I realized that I seemed to prefer speakers with lower sensitivity over those that were very sensitive. I didn’t hear a setup using a single ended tube amp that I lusted after. And I concluded that horn speakers aren’t my thing. They do some things very well but overall they just didn’t light my fire. But I can completely understand why some people love them.
My point here is that the sound resulting from the tradeoffs that low sensitivity speakers incorporate appeals to me for some reason. For the last 40 years I have been willing to invest in the amplification to drive these speakers and I’ve never regretted my decisions. Bottom line, high sensitivity or low sensitivity is not better or worse, it’s one of the many design decisions that speaker engineers make. Once they go a certain direction they optimize their design for the sound they want and sometimes that leads to low sensitivity and low impedance. I happen to be one of those audiophiles who is willing to suffer the cost and back problems of having an amp that will drive these things.
@erik_squires , thank you very much for that information on Siegfried Linkwitz's tone burst tests!
I was aware of the article in Stereophile years ago which "debunked" short-term thermal compression, but the methodology in the test was flawed because it looked at the average compression over time, rather than the rapid-onset compression that Linkwitz's test reveals.
"Bigger voice coil, more ventilation, lower power dissipation result in lower dynamic compression."
That's my understanding as well, but JBL went a step further in their M2 studio monitor: They use an alloy in the woofer's voice coil whose resistance stays essentially constant as it heats up. I'm not sure whether they did this for the compression drivers' dual voice coils as well. Anyway that seems to me like a brilliant idea which would be especially welcome in high-end audio speakers where efficiencies are lower and therefore voice coils are smaller.
For the record, my own priorities are much more focused on speaker/room interaction, and the types of drivers which do what I want in that area just happen to be fairly high efficiency.
Heh, I almost referenced JBL’s work in pro systems, as it’s among the most well documented and easy to find. Interesting 3rd way to skin this proverbial cat.
Also, I can’t type at all!
weather = whether
Also, while I believe it was Dr. Linkwitz, I cannot for sure remember, and I hope he doesn’t haunt me with bad crossover phase matching if I am mistaken in attribution. I do however remember the oscilloscope output very clearly. It was quite convincing.
While I do not need anywhere near JBL monitor style output, choosing tweeters with high power handling and very low measurable compression was a big goal for me.
I should point out that we should not attribute thermal compression to what might also be bad acoustics. Very reflective environments will have similar audible results, in at least as similar as you can type about them. A lot of bad / compressed treble complaints I’ve seen on audiogon were addressed with better room treatments. Was it excess reflection, or better treble/bass balance, or did the improvement in sound quality lead to turning down the knob, therefore reducing tweeter power dissipation? Really hard to say unless we are measuring. I sure could not explain in words how to hear a difference. :)
"
I should point out that we should not attribute thermal compression to
what might also be bad acoustics. Very reflective environments will have
similar audible results, in at least as similar as you can type about
them. A lot of bad / compressed treble complaints I’ve seen on audiogon
were addressed with better room treatments. Was it excess reflection, or
better treble/bass balance, or did the improvement in sound quality
lead to turning down the knob, therefore reducing tweeter power
dissipation? Really hard to say unless we are measuring. I sure could
not explain in words how to hear a difference. :)"
Your observation makes total sense to me.
Dynamic contrast can be viewed as a "signal-to-noise-ratio" thing, and to the extent that undesirable/excess reflections raise the effective in-room "noise floor", they reduce the system's dynamic contrast. I suspect this may be more common and/or often of greater audible significance than the short-term thermal compression revealed by those tone-burst tests.
This "signal to noise" ratio thing has implications for the sense of envelopment as well: The further down in level we can still detect the reverberation tails on the recording, the stronger the perception of the recording venue's hall ambience. (This isn't the only thing that matters for "envelopment" to take place, but imo it's one of them.)
The ear/brain system classifies reflections as such based on their spectral content, so imo it makes sense for absorption to be broadband, such that the spectral balance of the reflections is largely preserved (assuming they were spectrally correct to begin with). If the spectral content of the reflections is skewed too much, they are no longer classified by the ear/brain system as "signal", and so they become "noise".
Q: How has the sound of speakers changed over the years? Many yearn for the speakers of the past over those of today… what has changed? Distortion, materials, focus on sound characteristics?
A (by Mr. Timbers): Speakers have generally become smoother, more 3-dimensional and much smaller. This means that they are less dynamic on the whole and rather toy like compared to good stuff from the 60s and 70s. Unlike electronics, miniaturization is not a good thing with loudspeakers. There is no substitute for size and horsepower. Nothing much has changed with the laws of physics in the last 100 years so what it takes to make dynamic life-like sound is unchanged. There have been some advances in magnet materials and a bunch of progress in adhesives but not much else. The cost of a 70s system in today's economy would be considered unaffordable and the system would be deemed unnecessarily huge. The large highly efficient systems of old came at a time when 15 – 30 watts of power was the norm. Today's stuff would choke on those amplifiers. Now that power is cheap, size and efficiency has been thrown out the window because you can always apply more power. Unfortunately, more power does not make up for lack of efficiency. Today's speakers range between 0.1% to maybe 0.5% in efficiency. (On a good day) 60s and 70s stuff was more like 1% to 10%. With most of the losses gong to heat, turning up the power on a small system with small voice coils and poor heat management is definitely not equivalent to a large high efficient speaker.
It is true that the response of many of the old systems was a bit ragged and generally less attention was put in the crossover networks because simplicity generally means higher through-put. However, the big Altec's, JBL's, Klipsch's and Tannoys of the day would still fair well today with a little modernization of the enclosures and crossovers.
Today's multi-channel home theater setups let a bunch of small toy loudspeakers and a sub or two sound pretty big and impressive to the average Joe. I think speakers have mostly become a commodity and small size and price are what counts the most now. The few high-end brands left are struggling for market share in this age of ear buds.
The few high-end brands left are struggling for market share in this age of ear buds.
Thanks great post...
It explain to me why my Tannoy were so good.... 😁
Alas! i own them no more...(2 pairs)
Happily my Mission Cyrus help me to forget them, they are very well embedded in all 3 dimensions, then even if they are not on par in quality with the Tannoy, they sound better than my Tannoy non well embedded ever sounded to my ears...
I will not go further, the word "embeddings" is not very liked, being not understood....
My best to all...
A note: someone not tired to read all day long reviews of costly new electronical design possible "upgrades" said that my "evangelization" of people is too much for his ears.... It is unbeliveable that people are so gullible to throw their money without thinking about the way to use in the better way possible what they already own....
«You can change opinions, you cannot change science»- Harpo Marx
«It is like reverse engineering brother, you can change science and after that opinions change»-Groucho Marx
This "signal to noise" ratio thing has implications for the sense of
envelopment as well: The further down in level we can still detect the
reverberation tails on the recording, the stronger the perception of the
recording venue's hall ambience. (This isn't the only thing that
matters for "envelopment" to take place, but imo it's one of them.)
Hence why I will harp incessantly w.r.t. acoustics and take with a grain of salt many audiophile claims, especially after seeing listening rooms. Totally laughable when they then make claims about other people's systems not being resolving enough. But I digress.
Duke, I am not sure your friend has discovered something new, so much as documented what has previously been discovered, but not documented in the real world very much. This paper is a bit of an oldy, but still a goody. It's from 1992. Okay, it just seems old: https://pearl-hifi.com/06_Lit_Archive/15_Mfrs_Publications/Harman_Int%27l/AES-Other_Publications/LS_... There is a good discussion on driver structure as it relates to heat transfer. Interesting that relatively old Alnico, which is relatively inexpensive, but still more expensive than ceramic, has great thermal properties.
We audiophiles are to blame (well some of us are). Take one poor measurement to sound correlation (70s/80s and distortion), throw in another weak one (CDs), and as opposed to screaming for better measurements from manufacturers, we let them use it as an excuse to no longer provide measurements as opposed to providing better measurements. If your friend can measure it, then speaker manufacturers can, but they don't because measurements can't possibly tell you how something will sound ..... Oh well, reap what you sew.
Hence why I will harp incessantly w.r.t. acoustics and take with a grain
of salt many audiophile claims, especially after seeing listening
rooms. Totally laughable when they then make claims about other people's
systems not being resolving enough. But I digress.
I'm with you. What I think I have observed is
a - Self delusion b - A large variability in the ear brain mechanism being able to filter out room acoustics.
Based on what I know about machine learning, and neural nets, and observations at shows, I believe some listeners can pick out some delicate traits about system despite absolutely terrible rooms.
I personally, cannot. As studies in learning and acoustics have shown, filtering out noise is energy consuming. Your brain works harder in an acoustically messy environment and I absolutely feel it.
"As studies in learning and acoustics have shown, filtering out noise is energy consuming. Your brain works harder in an acoustically messy environment and I absolutely feel it."
Totally agree.
In home audio, "your brain works harder" = listening fatigue.
[public service announcement] In an acoustically messy environment like the back of a classroom (or even worse the back of a lecture hall), "your brain works harder" = you are straining to use ALL of your CPU power just to understand the individual words, and that takes not only more energy but also more TIME. So by the time you understand one word, the lecturer has already moved on to the next word, and you have neither the spare CPU power nor the TIME to comprehend complex concepts so that you can store them in your long-term memory. This is one of the reasons why the kids in the back of the classroom get tired within fifteen minutes and are by far the ones most likely to flunk. So even if they are shy introverts, tell your kid and grandkids to sit in the front if at all possible! [/p.s.a.]
Surprised that no one has mentioned “Hoffmann’s Iron Rule” in this discussion.
Josef Anton Hoffman was the “H” in the original KLH company. He was an audio engineer who theorized that you could only have two of the following in speaker design, never all three:
1. Small speaker enclosure 2. High efficiency 3. Accurate bass response
That is, if you want an efficient speaker with accurate bass, you cannot have a small speaker enclosure. Likewise, you can have a small speaker enclosure with good efficiency, but bass response and accuracy will be limited. My impression is that speaker design is primarily driven by that limitation when addressing SQ and efficiency.
Trying to dig it up, it's around here somewhere, but I had a good paper or two on electronic (DSP) correction of thermal compression both copper and magnetic. It is yet another reason why active speakers will rule the high end roost eventually. Passive will never be able to accomplish what active will be able to. For subs, active position feedback already can correct for this.
an unnatural treatment of room will also cause your brain to work harder....just evolution...find examples in natural environments that display broad band absorption like a 6-8” deep panel.... they don’t exist.....
ES, you will eventually tumble to time and phase.....
@tomic601 , that makes no sense at all. If you go into an actual natural environment, short of being in a cave, or very close to a cliff, or in front of a large tree, the only source of reflection is the ground, and normally that is dirt and somewhat soft (absorptive) ground cover. Trees by virtue of being somewhat round, make excellent diffusers. That negates your whole argument right there.
Also negating your argument is your room is not the recording studio, or the concert hall, or the church. For the most part you want to negate the impact of the room so that the acoustical cues in the recording are clearly communicated to the ears/brain and you hear what was recorded. Removing early/loud reflections via speaker placement, broad band absorbers, and diffusion absolutely will do this. Close late reflections are bad too.
I expect few people have actually heard stereo speakers in an anechoic chamber. Contrary to popular opinion, it is not bad at all, with pin point natural imaging. There is a big difference between audio reproduction and a new sound created in a room. Voices sound weird in an anechoic chamber because there is none of the expected echo. Recorded music sounds predominantly natural because the echos are already built into the recording. Your eyes and brain may be at odds though. That nature you mentioned? Predominantly it behaves more like an anechoic chamber w.r.t. music reproduction than it does the average listening room.
reread my post, i said zip about anything but absorption. take another run at finding a 6” absorber in nature. Its a hole in the acoustic space the brain is trying to reconstruct. I am a principal in a recording studio with a mobile location rack. You can catch up later.
the natural world is full of diffraction, most sterile audiophile rooms lack it bigtime...except for the forest of amplifiers blocking the path to the turntable ( which should be off to the side )
The GR Research high sensitivity speakers are, in a word, stunning. I had a pair of the old Super V's. Then a pair of Wedgies on top of 2x12 open baffle servo subs (flat to 20Hz at brutal levels). I'm getting ready to build a pair of NX-Tremes. Once one goes to really good open baffle speakers it is very, VERY hard to consider anything else. Watch these:
i spent a decent amount of my career in anechoic chambers testing advanced technology, simple stuff , some suborbital. my prefered vendor of loudspeakers ( since 1977 ) actually have and use a chamber for development and importantly production, doing the precise work of tuning to a standard and nulling. Do you have a chamber ?
@audio2design ,
Thank you for the link to the article. It is so sad that most audiophiles don't care about this one of the most important characteristics for speakers SQ.High efficient designs sound more alive, with better texture, micro and macro dynamics.In contrast - the high compression of low sensitive speakers masks important music information and causes listener fatigue. In addition, most audiophiles don't have a clue how good sound tube SET amplifiers (with the proper high efficiency speakers) are compared to any transistor amplifier design. Regards, Alex.
Thank you Tomic. I have heard it said that speakers for use in home music applications should NOT be voiced in an anechoic chamber as the effect of the room boundaries will be entirely lost. The result will be an artificial sound environment unrelated to the venue of any real performance. That seems to make sense to me.
For some comment on 18 inch woofers see my earlier posts.
Hi Alex. 9w SETs. You love 'em or hate 'em. They're not for me. I don't like high levels of third and fourth order distortion. For those that want it they do offer a caricatured inaccurate presentation of the programme, particularly in the bass where their lack of control allow the cones to slop all over the place. Neither are they relevant to my thread - it's about speakers.
There I don't buy your simplistic statement that efficient designs sound alive etc and inefficient speakers are compressed, mask important information and are fatiguing. That's just an unhelpful generalisation.
Wait, did we just enter the "speakers should be made of wood, brass and silver because that's what musical instruments are made of" world?
The principles of measuring a good sounding room have been well documented for decades. The measure of only using things that appear in nature is silly. Does your drywall reflect any sort of natural space?? No, it does not.
If the room acoustics aren't removing the excess noise, then your brain is, and that's tiring.
The thermal distortions in speakers and transistors have inertia and therefore are a heavier burden on our brain than conventional non-linear distortions. In addition, changing the impedance of the speakers changes the frequency of the speaker filters, which leads to different sound at different volumes and issues with frequency and phase response. Electrical Q is changed that changes bass response. The proper built SET don’t have issues with bass (with high efficient speakers). The problem is too many bad SET designs.
Sorry Duke, my bad. My point is that dynamics are a matter of volume. A speaker that can hit 110dB without compression is going to be more dynamic than a speaker that can only get to 100 dB even if it is less. efficient. Just a matter of power. Horns are very dynamic because they go very loud. They do it with less power because they tend to be very efficient. As far as sound quality goes, it's a toss up. Another issue is trying to run 15" woofers up to 700Hz then crossing to a horn. Two very dissimilar drivers crossed right in the meat of the midrange. You really have to push that crossover lower and in order to do it you are stuck adding a tweeter. I'm all in for limiting crossovers but horns have their limitations in this regard. This is what makes ESLs so special. You can easily get them to go from 100 Hz to 25kHz. Obviously you can make them go lower but IMHO you are much better off going to subwoofer especially if you can use a digital crossover. Audio2design, I know for fact you do not have to have active loud speakers to take advantage of digital signal processing. Perhaps it will be the way the market goes but I am not so sure and I am an unabashed huge fan of digital signal processing just check out my system page. Alexberger, in order to have inertia you have to have mass. Thermal distortion (whatever that is ) certainly has no mass. You are more than welcome to your SET amps. They are most definitely not my cup of tea. I have heard several speakers in an anechoic chamber and they sounded just fine. You can test your own by just moving them outside. Tuning a speaker in an anechoic environment is a fine way of achieving a flat curve or rather the curve you want. In order to tell what your speaker is really doing it is the only way. What happens in a room depends on the speaker's dispersion characteristics and the room itself. A speaker that is more directional will sound very similar in room as in an anechoic chamber. Controlled dispersion is the best room treatment you can get followed by digital room control (speaker control) and a few foam tiles.
voicing in a chamber would ignore room gain and reality, it’s a great tool for matching to a standard ( impulse, freq response, pair matching thru nulling ( hint ), etc.
For those dealing in the reality of listening in a room, RT 60 is the path to better sound.
You can use DSP to deal with non-linear behavior in a driver which are constant. You measure the output at say 90 db, and at 70 db, and you create transforms which adjust the output accordingly.
However, what I know of as thermal compression is not constant. The driver has a thermal history and changes behavior accordingly. That is, as the driver gets hotter it no longer behaves the same way. To compensate for this you would need to have an algorithm which has an accurate thermo-acoustic model for the speaker AND knows the actual voltages applied. That's a great deal of work vs. getting drivers which are thermally stable in their usable range.
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