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.
1+ ctsooner. The most expensive speakers I have even seen are not efficient at all. The Klipsch Horn is actually a good value in today's market. @audiokinesis, That makes perfect sense Duke. The radiation of the woofer will narrow down to that of the horn buy 700 Hz. It should work as long as the driver is not colored. The speakers that I have heard that run a 15" woofer that high have been colored. Again the K horn is a good example and I think they moved the lower crossover to 350 Hz from 500 Hz. If you manage to avoid another crossover point that would be great. @atmasphere, I do not disagree. Thermal compression exists but good drivers take this into account, ventilation, ferrofluid, etc. So, to what degree does this effect the sound we hear at home, at the volumes we listen at. The only drivers I have are subwoofers and with the system going as loud as I'll ever play it they are just loafing along. I would think ESLs would be more limited by mechanical compression than anything else. I'm not sure but I do not think they heat up at all. The transformers certainly stay cold. Transformer saturation might be an issue.
@audio2design, I doubt anyone is going to jamb a tube or class A amp into a speaker enclosure. You can add DSP control to any system. Check out DEQX and Trinnov. The problems with active loudspeakers are, audiophiles tend to shy away from all in one stuff. Right now this market is with equipment like Sonos. Great for TV and background music, not to hot for overall sound quality. The companies that make this stuff and have the horsepower to do it are not interested in audiophiles. Not enough of us. They are marketing to the masses who do not like big speakers, do not want to spend a gazillion dollars on equipment and are not critical listeners. I also doubt they would ever go near an 8 foot ESL. Amar Bose was a brilliant guy but lets face it, the 901 was not a great speaker. He sold a bunch of them jumpstarting a huge company with lots of horsepower. Look what they make now. How is Meridian doing? You certainly do not see a lot of their systems in the US. Audiophiles have a tendency to be digital and processor phobic. The last thing a died in the wool Vinyl listener wants is a computer in his speaker.
Guys, it's simply not true to make a statement that a higher sensitivity
speaker is more costly to make. Drivers, cabinet material, R&D,
spikes, connectors, wire, glues, finishes.... and of course how many
points dealers get to sell them
Let's be clear about one thing: Sensitivity isn't the same thing as Efficiency and it really is the latter which is the focus of this thread. You can build a high sensitivity speaker by simply taking a number of low efficiency drivers and putting them in parallel. Cheap and high sensitivity, but its efficiency will remain low. High Efficiency cannot be achieved cheaply for the simple fact that there is a much higher degree of precision needed in the construction of the driver's motor.
The difference between Sensitivity and Efficiency: The former is 2.83Volts at one meter. The latter is 1 watt 1 meter. If the speaker is 8 ohms the two are the same. If we take four 8 ohm drivers that are 87dB and put them in parallel, the load is now 2 ohms. The sensitivity is increased by 6dB; 93dB doesn't sound too bad. But that is 2.83volts into 2 ohms; when you do the math that is 4 watts. If you put 1 watt into that same array you'll still get 87dB. A higher efficiency driver that can make 98dB with 1 watt and is 8 ohms is a different beast altogether. This describes the 15" drivers in my speakers at home and they cost $2000.00 each.
You can find 15" drivers that cost $200.00. I'd be very interested to learn of a 15" with the same 22Hz free air resonance and 150 watt power handling that cost $200, or even $600.00. Have at it! But I think you'll find that such simply does not exist.
Others have said that higher sensitivity speakers have to be larger in order to transduce low frequencies at the correct levels. Also that driver manufacturing tolerances are tighter. Both these increase costs.
But if that's not correct then you must go back to my original post and tell me why all manufacturers don't build high sensitivity speakers, rather than only a small minority.
Guys, it's simply not true to make a statement that a higher sensitivity speaker is more costly to make. Drivers, cabinet material, R&D, spikes, connectors, wire, glues, finishes.... and of course how many points dealers get to sell them if selling through conventional means will determine costs, not sensitivity.
Excellent @glubson. From the fertile mind of Bruce Thigpen, the Eminent Technology TRW-17 Rotary Subwoofer, for the bottom octave (20-40Hz) down (fed enough power, flat to 1Hz!).
High sensitivity speakers cost more to make and lets not forget that higher efficiency speakers with higher impedance cost even more to make but it all comes down to good quality design for any speaker to make them perform and sound good you will know when you find the right one for your ears because all sounds will just sound right to your ears.
You don’t have to have a highly efficient speaker to overcome dynamic compression in normal usage.
Now, before you tell me what I don’t know and need to know, consider the following:
What system constellation as it pertains to minimum cone diameter, sensitivity rating and wattage would, according to you, be able to deliver sufficient SPL coverage for "normal usage" with a room size of, say, up 30 square meters (or, no more than ~3,000 cf. total volume) - as an active design with the whole none off-the-shelf trimmings, that is, so to stay on your home field? Room acoustics per your preference here.
Enough for a while with any further elaborations of all the exclusivities in regards to tailored driver design, impedance matched amps, measurement methods, analysis and DSP tools and other sheer engineering prowess. Let’s get some blunt, physical requirements in place as per the above.
As the article points out, there are methods of voice coil design, speaker design, material choices, etc. that can all mitigate these problems, hence probably why there are 100’s if not 1000+ speaker designers, but very few professional driver manufacturers, and why top speaker companies design their own drivers.
Would said mitigations make up for what bigger and more efficient drivers incorporating horn- or waveguide loading with compression drivers could do in regards to fairly uninhibited dynamics? What’s sufficient SPL-wise, even? How about headroom - lots of it; does that make of sonic difference to you, the ease that comes from using lots of radiation area and high efficiency?
One thing would be an acknowledgement of the above as a stand-alone factor; another whether it’s compatible with a commercial design meant for sale with all that entails and the size restrictions and other that typically follows here. It’s a convenient stance implicitly claiming what’s "sufficient" for normal usage, likely catering to a product development of one’s own within said limitations, when setting the bar higher in that regard could make a worthwhile difference to some - non-commercial it may be as a product range.
It is also a reason why active speakers will be necessary for the absolute in sound recreation.
Reproduction of sound/music, is NOT the same as creation of sound/music.
Ok i will not answer to all your distortion of my points...
Except these one...
Pure "Reproduction" of sound/music is IMPOSSIBLE in practice... It is a path where each foot is placed on diverging choices.... The management of these choices are what i called a "recreation" of what was a musical creation in a living stage or room...But you dont answered that point at all...You only call me ignorant like it was an argument....Recording engineer by the way are not only scientist but artist for this reason...
I cite Toole about reflections and someone who contradict him, just to relativize your own DOGMATIC affirmation that all primary reflection are bad... You distorted my intention like usual..Read your own posts before answering me . Or keep a red string in your head....Even late reflections can be good if wisely used by the way...
I contested not, the fact that nature lack walls and reflections, 😊 but your false assimilation of nature and an anechoic chamber, remember?.... Here also you distorted my intention...
I will let you with a tidbit to pounder also with the same arrogance you always keep with any " ignorant audiophile"...
Why do you think speech is badly perceived in an anechoic chamber?
A clue: Most headphones have ALSO a room with reflections...This is their shell....
I already have a life and i try to not attack other audiophiles with my dogmas....It is not your case... Practical acoustic is an art based science not a science, like medecine is an art by the way...
«Ignorance come first from what we know, not from what we dont understand»- Anonymus Smith
You don't have to have a highly efficient speaker to overcome dynamic compression in normal usage. As the article points out, there are methods of voice coil design, speaker design, material choices, etc. that can all mitigate these problems, hence probably why there are 100's if not 1000+ speaker designers, but very few professional driver manufacturers, and why top speaker companies design their own drivers. It is also a reason why active speakers will be necessary for the absolute in sound recreation.
Mahgister, This will be my last reply to you because you continue to demonstrate no ability to understand or from where I am standing even attempt to understand. You just get your self all in a huff and go nay nay nay about stuff you are grossly and woefully lacking knowledge on. You embarrass yourself.
It is a fact verified by science that speech recognition is greatly improved with some early reflections... Which one and the timing with late reflections is an acoustical complex problem not to be solved by dogmatical ignorance...
Clearly you don’t understand the discussion, but feel free to clog the thread with ramblings. Reproduction of sound/music, is NOT the same as creation of sound/music. Most music is mixed near field in setups that tend to have little in the way of early reflections. I am sorry that you cannot understand the difference between recording speech in an anechoic chamber and playing back speech recorded in a regular room and then played back on stereo speakers in an anechoic chamber. Have you never used headphones?
Floyd Toole specifically talks about using reflections to gain a sense of space. That is a taste thing. Gain space, loose imaging. You will note in my comment about imaging of stereo speakers in an anechoic chamber being laser focused. Want to guess why that is? Try to think more, and contradict me without adequate information less. You may learn something.
«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.»
Complete non sense... Read what musician think about that in this link:
Again, you clearly do not understand, even though I repeated it, several times, that creation of sounds/music is much much different from reproducing it. I don’t know what else I can say except spend more time reading (listening) and understanding and less time reacting. You will be farther ahead.
The rest of your diatribe / attempted attack on what I wrote is just more of the same so wasting my time pointing out what you wrote that is wrong (probably all of it, I got bored reading it) would waste my time and clog the thread.
I will leave you with a little tidbit. Do you know what a lot of enterprising hobbyists do who can’t afford anechoic chambers, and need better measurements do when building speakers? .... They take them outside. Why? -- no reflections (again! except the ground as noted).
Have a nice life Mahgister.
p.s. "Sound in an anechoic chamber sound a bit like headphone, said Floyd Toole, the sound is in our head" ..... this is not remotely true. Not at all. I am not sure why Floyd Toole said it, and several, including me, who have heard stereo playback in an anechoic chamber called him on out on it. Usually (almost always) people only have 1 speaker in an anechoic chamber, so it is quite possible he never actually heard stereo playback in an anechoic chamber even with all his experience and was talking off the cuff. I was doing contract research on some advanced signal processing and had multiple speakers in the chamber. IF, and it is a big IF, you actually thought this through, in an anechoic chamber, with stereo speakers, all the social clues are there for angular position, depth, and some simulated height potentially from frequency shaping. None of that changes in an anechoic chamber. In fact, absent reflections, these items are all clearer.
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.
Thermal compression occurs with all voice coils. The less efficient the driver, in general there will also be greater thermal compression as the speaker is being asked to deal with more power. As the voice coil heats up (which it does on each individual bass note; yes, they can heat that fast) its ability to move the speaker cone is reduced. Result: lower efficiency speakers tend to have lower dynamic qualities as well and unless you move away from a voice coil M.O., you can't throw more power at it, more power makes it worse. IOW the louder you play, the more compressed it becomes.
"Another area where attribution is difficult, the dynamic nature of high efficiency systems.
"Is it that, or is it the controlled dispersion?
"I'm
not saying low compression speakers aren't good. I'm saying that some
of what we may attribute to "fast" or high impact speakers is really
just better room integration."
I totally agree.
I would not be surprised to learn that, in practice, room acoustics and radiation patterns usually play as big if not bigger role in real-world dynamic contrast as thermal compression.
Mijostyn wrote:
"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."
Agreed.
Mijostyn again: "Another issue is trying to run 15" woofers up to 700Hz then crossing to a
horn."
I understand your skepticsm.
Intuitively it sure seems wrong because it's almost never done in home audio. Actually, running a 15" woofer to 700 Hz is like running a 5" woofer to 2.1 kHz: For the right kind of 15" woofer, it's a piece of cake. (The 15" midwoofer I'm using is plus or minus 1 dB to about 1.7 kHz with no filtering, then it has a 3 dB peak at 2 kHz. Its effective motor-strength-to-moving-mass ratio surpasses every small high-end midwoofer I know of, and falls in the ballpark of 5" cone midranges.)
Some of the finest studio monitors in the world, the classic Augspurgers and the magnificent JBL M2, use the 15" woofer + horn format. There are several brief YouTube videos about the M2 which are imo worth watching.
Mijostyn: "Two very dissimilar drivers crossed right in the meat of the
midrange."
The big woofers and horn-loaded compression drivers are visually dissimilar, but ACOUSTICALLY they are far more similar than most cone midwoof/dome tweet combinations in the crossover region. Let me explain:
What we hear is a combination of the direct sound and the reverberant sound, the latter being dominated by the speaker's off-axis response. Ideally the off-axis response tracks the on-axis response very closely. However if there is a directivity mis-match in the crossover region, it is impossible for the on-axis response to match the off-axis response through the crossover region.
A directivity mis-match in the crossover region is almost inevitable for a cone midwoof/dome tweet combination, because the cone's radiation pattern will be narrower than the smaller dome's radiation pattern. There are two ways around this: One is to widen the midwoofer's pattern by using (hopefully well-behaved) cone breakup, and the other is to use a horn or waveguide of some sort to deliberately narrow the tweeter's radiation pattern so that it matches the midwoofer's.
The latter is what I do, only at a lower frequency than most midwoof/tweet combinations.
Crossover frequencies are a juggling of tradeoffs. Briefly, for a combination of psychoacoustic and practical reasons, imo 700 Hz makes sense. It arguably makes better psychoacoustic sense than just about any higher frequency does.
So like I said I understand your skepticism, but I've put some thought into my (often unorthodox) design decisions.
Another area where attribution is difficult, the dynamic nature of high efficiency systems.
Is it that, or is it the controlled dispersion?
I'm not saying low compression speakers aren't good. I'm saying that some of what we may attribute to "fast" or high impact speakers is really just better room integration.
Amazing how you can take a slow, muddy, small sounding speaker and transform it with the appropriate room treatment, or how a poor room will sound better with tightly controlled speakers like horns, ESL's and open baffle.
«audio2design to @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. That nature you mentioned? Predominantly it behaves more like an anechoic chamber w.r.t. music reproduction than it does the average listening room.»
Complete non sense, an anechoic chamber ideal is absolute silence measured in Db....Nature is anything except absolute artificially designed "silence" measured in Db....
«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.»
Complete non sense the recording cues from different microphones and different location are RECREATION after trade-off choices from the recording engineer, not PURE reproduction....Then for the most part we want our room to be an helper to facilitate the concrete recreation of our experience of timbre; the information about timbre being partially lost or distorted by virtue of the trade -off choices in the recording process....Our room can compensate and facilitate or impede this natural recreation....
«Removing early/loud reflections via speaker placement, broad band absorbers, and diffusion absolutely will do this. Close late reflections are bad too.»
Complete non sense, because first: even world-known acousticians are not in complete agreement about the suppresion or partial use of the early reflections...read this article where Floyd Toole speak positively about using some early reflections but is criticized for that...
It is a fact verified by science that speech recognition is greatly improved with some early reflections... Which one and the timing with late reflections is an acoustical complex problem not to be solved by dogmatical ignorance...
«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.»
Complete non sense... Read what musician think about that in this link:
«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.»
Another nonsense here....What is true for some aspect of imaging is NOT true for timbre perception...These phenonema are correlated yes but not reducible ONLY to frequencies accuracy...
Sound in an anechoic chamber sound a bit like headphone, said Floyd Toole, the sound is in our head...In nature sound dont live in our head , for our survival we must locate sounds and identify clearly speech articulation....Then the metaphor comparing nature lack of echoing walls and anechoic chamber is bullshit....The level of sound recorded in a silent desert cannot be compared to an anechoic chamber by a margin measured around +30 Db......You dont jump because of your heartbeats in a desert, in an echoic chamber you do.... It is even dangerous to live there more than 45 minutes for many people....
"Recorded music sounds predominantly natural because the echoes are already built in the recording" is non sense because it is not the echoes that are built in in the recording but some information about the original room where the musical instrument were recorded with a lost of information and his inevitable distortion by the inevitable trade-off i spoke about linked to the choices made by the engineer between for example the 4 different kind of microphones he can use and their specific location...Not one microphone can record the same information even at the same location....These choices implicate a distortion in the information recorded about timbre for example...
The audiophile room is precisely what can help the recreation of a more natural sound if rightfully designed or acoustically treated, not only to erase some bad timing actions from the walls, but to use and take advantages from some others... It is called positive timing acoustical events...This information coming from our room can help us to recreate the natural timbre of the initial instrument in his living location and compensate in some way for the lost of information or the distorsion of the information coming with the recording process....
I will conclude by saying that the decision to voice or not speakers in an anechoic room is a technical matter in the hand of speakers designer specialist...BUT thinking that an anechoic chamber is good for a musical experience is ridiculous...Designers of speakers can and must ask for EXPERIMENTAL conditions that have NOTHING to do with immediate musical listening conditions and are more linked to the improving process of the limitations of their structural design... Ignorance only can confuse together, digitalisation of sound, acoustical and/or musical information... They are related but are 3 different events or process....
Then pretending that anechoic chamber reveal more information because frequencies perceptions are more "pure" is ignorance clothing in knowledge... It is like pretending that flying ourself in an aerodynamic chamber or a wind tunnel is the more truthful experience for flying...
Confusing the resistance of the parts of a plane in a wind tunnel with real flying action and impression, is like pretending that the more" accurate" frequencies perception and imaging in an anechoic chamber "sounded more natural" than in a treated acoustical room using reflection and timing events created for human ears to recreate musical timbre and not only imaging ...
Perhaps robot will prefer anechoic chamber....They dont like what seems to them" useless" information, like the "colors" of a stradivarius compared to an ordinary or mediocre violin....Like us humans....😁
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.
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.
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.
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.
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.
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.
@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.
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 ?
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:
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 )
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.
@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.
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.....
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.
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.
"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.]
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.
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.
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
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.
"
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".
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. :)
@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.
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.
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.
"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.
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.
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.
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.
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