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In Reply to: Re: I'm just not sure about one thing posted by morricab on November 10, 2006 at 03:33:42:
This is the comment you made, and I already linked the post:morricab
"I shudder to think how bad your speakers must be if you can't hear the difference between a good tube amp and a crown amp."
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
Follow Ups:
Well maybe if you told me your speakers I would no longer think it was your speakers that can't resolve the differences...just your ears.
Of course, that part of the sentence is incorrect, totally made up, not anything I have said, and I addressed that in the post below it. Of course I have come expect that sort of thing from tubeguy, E-stat, sometimes Clark, and now perhaps I'll have to expect it from you.
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
I see now why you are obssessed with NRC measurements and FR response because you own paradigms. I was also kind of that way when I owned them because afterall it is sort of the their USP. You have to believe their marketing hype to buy the speakers of course. Oh and they don't sound too bad...but not great either.What I realized along the way in this journey is that flat FR is one of the easiest things to fix and not even that important to getting a live sounding system. Transparency, coherenecy (including the time domain), low level resolution, dynamics, freedom from compression, low coloration, and low distortion are all just as important and more importantly, not correctable by DSP.
You are apparently still in that stage of the audio hobby where you think the speaker is the only or at least by far the most important part of a system. This is most likely due to the fact that you have only mediocre components in your system. Switching with other mediocre components brings no real improvement. Of course one needs a sufficiently resolving speaker to begin with. You can do much better than the Paradigm S2 (not new maybe but there are plenty of better used speakers to be found). You can do seriously better (the whole system that is) for not that much money.
What I have found is that once you have a speaker that is truly transparent, low in coloration, high in coherency (means time aligned or single driver usually), low in distortion, and highly resolving of low level information (something paradigms do not excel at doing) then the speaker no long becomes the limiting factor in your system. Gear differences become so obvious that you wonder why others even argue about it.
The NRC measurements are probably the most accurate available to me and they work pretty well for me. They are a useful screening tool, and I see absolutely no reason to consider speakers that don't measure reasonably well. Such speakers don't sound good to me. Measurements are a tool and I fail to see anything obsessive about that.As I've sometimes said before, the kind of measurements available to me can tell me what speakers not to get but they can't tell me which ones to buy.
Let's look at the factors you propose:
-Transparency: a piece of optical imagery, not really very clear in its application to audio. Some mean sonic invisibility, in which respect the S2 is excellent. Otherwise, this must require an even FR.
-coherency (including the time domain): God knows what you mean by coherency. Time and phase coherence do not seem to be that important in speakers save as they affect the FR. In any case, the S2 is subjectively very quick, and I have owned Quad ESL-63's, but they don't really fit our room acoustics very well. The S2's sound better here.
-low level resolution: I wonder whether people who use such jargon have any idea what they are talking about.
-dynamics: this usually refers to punch in the bass. Anyway, I listen well within the dynamic limits of my speakers.
-freedom from compression: Soundstage has begun to measure this and even an inexpensive PSB speaker seems to do well in this respect.
-low coloration: And you were denigrating the importance of even frequency response? GMAB But of course, the dispersion counts, too, not merely the on axis response.
-and low distortion: well, Soundstage has measured this for quite a while and the S2 does pretty well.
-Resolution is something you also mention: it's also an optical image whose applicability to audio is again not too clear. I suppose it means one can hear what's on the recording.
"Gear differences become so obvious that you wonder why others even argue about it."
Gee, I want to listen to music, not gear differences.
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
Well the fact that you have difficulty understanding some generally accepted audio language makes this discussion rather difficult, or are you merely being obtuse? I assumed that at least some of these definitions are obvious and at least a few have been explained and discussed enough that you know what I mean.However; I will address the points and give you what I am thinking about when I use these terms.
1) I never said even frequency response wasn't important, just less important than you give it credit because of its relative ease of correction. With modern DSP, FR is the least of a speaker designer's worries.
2) Transparency "a piece of optical imagery, not really very clear in its application to audio"
You are the only one who would question this. Yes it is an optical analogy but one that is quite clear (no pun intended) to most people because the auditory equivalent is the feeling that there is nothing between you and the original sound. It mainfests itself in that on recordings with natural acoustic one can hear the ambience in the recording clearly, for example. In this sense it is related to low level resolution but low level resolution also includes clearly perceiving subtle dynamic shifts at low levels, not simply did you hear the sound or not. Does the character of the instrument retain the correct timbre and expression at that low level or is it indistinct?
3) Coherency: The sense that the sound is coming from a unified source and not multiple sources. Nearly every box speaker betrays the drivers it uses to make sound. This is due to crossover anamolies, differing driver materials, sharp cutoff, cone resonances etc. Time coherence is another matter and why I put it in parenthesis. It has been my experience that speakers which are time coherent (for example full-range electrostats or a speaker like the Thiel CS3.6) are also more coherent in the first sense of the word. An example of one of the least coherent speakers I know is the B&W 802N. This speaker uses a different material for each driver and high order slopes. Hearing the transition between drivers is painfully obvious as a change in the coloration of the timbre of instruments. It has very little to do with FR.
4) Low level resolution: see point 2 above. I will repeat, it is not just if you can hear a soft sound or not (although with some speakers and systems this is an issue) but if that soft sound retains the complete characteristics of the thing making the sound, including dynamics and timbre. MOST speakers in the world have problems at the low level sounds. Nearly all conventional medium to low sensitivity speakers fail miserably.
Example: Some friends of mine have Apogee Scintillas. These are very high resolution speakers; however they are a bit old and one friend has had them rebuilt and the other has a stock pair. They did a speaker cable test (quite important with a 1 ohm speaker) comparing the Speltz anticables to some DIY silver cables. They did this test on the rebuilt Scintillas that have the same DIY silver cable as internal wiring. They had a track of a new woman singer from Norway done in what seems to be a home studio. On one track they noticed very quiet in the background a dog barking(presumably outside the studio). They had not noticed this with the anticables but it was clearly audible with the silver cables. When they went back to the anticables and listened carefully for the dog THEN they heard it. However; it was much less distinct and barely noticable as a dog. Back to the silver cables and the dog was distinct with timbre of its voice and probably even would be recognizable to the owner. Oh they were using only 1/2 meter long cables and this was still obvious.
The other friend took the recording home on his stock Scintillas, which are wired with 20 year old Monster cable and he has 3 meter speaker cables. He couldn't hear the dog at all!!! It was simply not there no matter how hard he tried to hear it and even knowing exactly where it came in. Clearly information was being lost and now he is going to have his speaker cables shortened and rewire his speakers. This is an obvious example of what I mean by low level resolution.
5) Dynamics. This has nothing to do specifically with bass. Does a trumpet's blast rely on bass response? What about a Cymbal crash? Dynamics has to do with a speaker's or system's ability to go from one level to another level with lifelike speed and in the case of big amplitude shifts do so at ALL frequencies equally and without compression. Not just bass. Speakers that are restricted in dynamics in some frequency band will exhibit a certain "character" that is not obvious from a FR measurement (same is true for amps and sources). If a speaker sounds "dark" even though the FR is nearly flat then it suggests that the high frequencies don't have the same dynamic character as the mids or bass. If it sounds bright and the response is relatively flat then it is possible that the bass driver has begun compression whereas the mid and tweeter have not.
"Anyway, I listen well within the dynamic limits of my speakers"
Do you? Probably if you listen only to compressed music then you are right. If you listen to relatively uncompressed jazz or classical then I doubt it.
Let's be clear: Dynamic range is not just about how loud something can play. It is also about how SOFT a speaker can play and retain the correct character of the instruments (see my thoughts on low level resolution). The key word here is RANGE. From soft to loud not loud to louder. If you listen to an orchestra at REALISTIC levels then how good is your system through the soft passages and does it make it through the loud ones uncompressed? That is what I mean by dynamics and dynamic range.
6) Freedom from compression: Soundstage's measurements are steady state and not necessarily indicative of dynamic conditions.
I have seen studies that show 86 db/watt drivers that begin to show the effects of thermal compression as low as 90 db. Normally, doubling the power gets you 3db more output from the speaker. What they found was that above 90 db or so they were getting only about 2 db per doubling of power and then at higher levels only about 1 db. Eventually the driver will cease to get louder and you will probably melt the voice coil. VCs can heat up very quickly on big sudden peaks and are relatively slow to cool down thus affecting the signal that follows the big transient. This is called hysteresis and its reality is that big dynamic peaks DO compress for most drivers and at lower volume levels for lower sensitivity drivers. Tweeters are often much higher sensitivity than woofers in normal speakers. Many speakers get edgy sounding when pushed. Is it distortion?? Maybe. Cone breakup? maybe or maybe its also a momentary imbalance between the outputs of the drivers due to thermal compression.7) Low coloration: This has very little to do with FR so I am not sure why you bring it up. Coloration is the sound the speaker makes by itself when the drivers are in motion and is correlated with but not a part of the actual signal that was put into the speaker and what the drivers are putting out. This manifests itself as: Harmonic distortion, driver flexing colorations, cabinet energy storage and release, crossover anamolies, resonances etc. This altogether can be thought of as "self-noise" or the noise the speaker makes itself that is not part of the original signal. It rides typically 10-30 db BELOW the main FR and rarely, with exception of strong resonances, makes a noticeable impact on the FR. However; it is most definitely audible and probably one of the main reasons that two speakers, even perfectly corrected for FR can sound very different (along with dynamic behavior).
Often, the lower the speaker's "self-noise" the better that speaker will retrieve low level information while retaining the proper character of the sound. Transparency and natural soundstage will also improve (assuming the recording is made in a natural space). Most speakers are so "noisy" that most people don't even realize that all that garbage is riding along until most of it is gone. This relative lack of "self-noise" (all speakers have some) is one of the reasons (along with freedom from compression and dynamics) why big Wilson speakers (like the MAXX and X2) can sound quite lifelike despite their relatively poor FR.
8) "Resolution is something you also mention: it's also an optical image whose applicability to audio is again not too clear. I suppose it means one can hear what's on the recording."
See points 2 and 4 its not just what's on the recording but if the correct character of that thing is properly preserved. When I say high resolution I am also including the other points like dynamics, coloration, and transparency. Clearly there is some overlap in the terms and some terms are used in the definition of others. We use optical analogies because they are ones that are easier to understand. It is not easy to describe hearing phenomena.
""Gear differences become so obvious that you wonder why others even argue about it."Gee, I want to listen to music, not gear differences. "
This is a disingenous statement and a cop out because obviously in this discussion we are talking about how the gear affects our perception of music. A high resolution speaker will give you insight into which gear and cables are giving you the full information and which ones have audible problems. However; if the speaker is mucking things up too much then the ability is flawed. You can still hear differences but it becomes more difficult to tell different from right or wrong.
The right speaker and right gear will give you more of what is on the recording and presuming the recording is a good one then more music.
I've heard much of the jargon in the audio subculture. Sorry, I just don't think most of it makes sense.I may or may not be the only one who questions the use of optical imagery in audio. For example, we have an idea what transparent means in relation to glass. It means you can see through it. Now, in audio, you explicitly relate it to feelings: "the feeling that there is nothing between you and the original sound." Nothing objective there.
Ah yes! The B & W 802N, a speaker I have heard and which certainly is not invisible. I didn't like it, either. I suspect the uneven off axis dispersion below the crossover between the midrange and the tweeter is one fault. When one talks of FR with speakers one must really include dispersion as well.
As is clear from my Inmate Systems entry, I listen mostly to classical music.
I'm so far not into DSP.
I don't know about barking dogs. Don't usually hear them at concerts. Sounds like a noise floor issue to me but then we really don't know what is going on. And you never will as long as you continute with your 'black box' approach of simply swapping pieces. I should also point out that, even as stated from your own perspective, you have not traced the problem to speakers. Do you mean that the barking dog can't be heard on other speakers?
I am simply astonished by your assertion the FR has little to do with coloration! You put it down to distortion. In any case, the distortion of my speakers is quite low at normal listening levels.
Dynamics--well Soundstage is beginning to measure compression, and did so with this inexpensive but nice measuring speaker:
http://www.soundstagemagazine.com/measurements/speakers/psb_image_t45/
Low level resolution seems to have a lot to do with Fletcher-Munson effects, also noise levels.
There are a number of things I can think of that effect whether a speaker sounds harsh at high levels. Fletcher-Munson effects can do that, too, among other things. So we haven't gotten totally away from FR.
"A high resolution speaker will give you insight into which gear and cables are giving you the full information and which ones have audible problems. However; if the speaker is mucking things up too much then the ability is flawed."
Well, there we are into optical imagery again. I'm afraid that a 1 ohm speaker will help create problems with a lot of amplifiers which can't drive it. I can't see that that makes it particularly revealing otherwise, or that it has much applicability to speakers designed more sensibly. If I wanted to drive Apogee Scintillas, I would get much bigger amp amp with lots of current capability. But my amp seems quite adequate to drive most speakers, including the Quad ESL-63 and my Paradigm Signatures S2's. I fail to see, for example, that the speakers are mucking things up just because less powerful amps can drive them.
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
"Nothing objective there"
Not so. It is an observation based on what one is hearing. This can be quite objective and reproducible. Not all complex reactions to what one observes can be easily described in language. This is why we use visual analogies becuase language is far better at explaining visual observations than auditory ones. This is probably because human vision is a more highly developed sense and thus more directly related to our survival."When one talks of FR with speakers one must really include dispersion as well."
I am always referring to room response...never simply on-axis response.
"I don't know about barking dogs. Don't usually hear them at concerts"
You miss the point. I doubt it is noise floor in the conventional sense. I have heard his system and there is no hiss or hum.
"And you never will as long as you continute with your 'black box' approach of simply swapping pieces"
I have no "black box" approach just by swapping pieces. I think about the why and then think about which pieces are most likely to affect that. This is also what my friends have done with regard to the wire. See the problem is that you invalidate observation and experiment as invalid tools for making a correct sounding hifi system and I tell you that it is essential to having a correct sounding system. You observe a phenomenon, change a thing, then observe again. Eventually, insight can be had without having to change all the time. This is experience from experiment and observation...something you seem hell bent on denying yourself. My friends and I are careful observers and not afraid to find the root cause.
"Do you mean that the barking dog can't be heard on other speakers?"
That is one possible implication. It is also possible that the other friend's system is lacking resolution elsewhere. If he swaps the wiring and finds the dog barking is still missing then obviously the problem was not simply the wiring, although replacing 20 year old copper wire that is probably not oxygen free and therefore corroded is not a bad idea.
"I am simply astonished by your assertion the FR has little to do with coloration! You put it down to distortion. In any case, the distortion of my speakers is quite low at normal listening levels."
That is not what I said. It does of course affect timbre of instruments but again it is easily correctable so who cares. I don't put it down to distortion in the sense you are thinking of distortion, ie. Harmonic distortion. By this measure, most modern speakers are quite low in level and harmonic order. I am talking about NON-harmonic distortions, cone self-noise, cabinet energy storage, port resonances, thermal compression, dynamic compression etc. etc. Paradigm doesn't specify these things and therefore you have no idea if your speakers are low in this kind of distortion or not. You seem very obtuse about these very important aspects of speaker design.
"There are a number of things I can think of that effect whether a speaker sounds harsh at high levels. Fletcher-Munson effects can do that, too, among other things. So we haven't gotten totally away from FR"
No one is suggesting that FR is not an issue. In fact it is probably momentary, ie. during peaks, FR imbalances that make things sound bright or dark. This issue though isn't the FR but what causes the FR to become imbalanced? This goes back then to compression and the like. FR is the symptom in this case not the cause. The speaker might measure flat at a constant level but heat up the woofer VC and how it behaves differently from the tweeter, which has a different thermal compression curve, not to mention a different amount of energy being put into it.
"A high resolution speaker will give you insight into which gear and cables are giving you the full information and which ones have audible problems. However; if the speaker is mucking things up too much then the ability is flawed."
Well, there we are into optical imagery again. "
How so? I see no optical imagery in that quote. Resolution is a general term not necessarily related to vision.
"I'm afraid that a 1 ohm speaker will help create problems with a lot of amplifiers which can't drive it."
Maybe so but we are talking about changing cables with the same amplifiers that ARE capable of driving it.
"I can't see that that makes it particularly revealing otherwise, or that it has much applicability to speakers designed more sensibly."
What about ultra low mass, low coloration, low distortion drivers with essentially NO thermal compression (only dynamic compression at high levels)? This means the speaker retains the same character over very wide dynamic range (particularly as you go down in level). This is what the Scintilla brings to the table along with a pretty smooth FR. The character is maintained even at very low drive levels...something most dynamic speakers fail miserably at (including paradigm). Normal suspension cone drivers have to much resistance to motion at low input levels (overcoming surrounds and spider mechanical resistances necessarily limits what input signal gets a motion out).
"I fail to see, for example, that the speakers are mucking things up just because less powerful amps can drive them."
You fail to see this because no one said this. I am generally an advocate for lower powered amps anyway. I see the fact that the Scintilla needs a high current amp as its one true weakness. Its why I like other, easier to drive Apogees better overall.
A speaker mucking things is not directly correlated to its ease of drive. Lowthers muck things up pretty badly in a lot of ways: poor FR, no bass, highly colored "paper" sound. However; they are highly efficient (100db watt), which means that they move a lot with very little input and thus do superb low level reproduction and within their limits are highly dynamic. They have the opposite problems of most conventional speakers that get the FR right and maybe have less coloration but are really undynamic sounding because they don't play soft well nor do they play loudly well.
You just told me that the “auditory equivalent” of transparency “is the feeling that there is nothing between you and the original sound.” There is nothing objective in that definition and it says really nothing about the equipment or its performance but about feelings.I also fail to see that I have denied anything in your observations. Hearing a barking dog seems off hand a fairly unambiguous thing. I do wonder about your explanations, though. Here is one of the things you said about your methodology: “I think about the why and then think about which pieces are most likely to affect that.” You still don’t know technically why the barking dog is heard in one case and not another. What on earth is that wire doing? You don’t really know and that’s why I call it a black box methodology, although perhaps “plug and play” would be more appropriate. Plug and play is suitable for some types of problems, of course, like troubleshooting by a process of elimination.
"Dynamic" seems to mean different things to different people. There's one fellow here who touts his speakers, which have a hump in the upper bass to lower midrange area, who then regards some other speakers which are capable of pretty high output in that area as undynamic. Parenthetically, I think a driver is much more likely to heat up on steady signals than short transients--in the old Audio magazine, they tested some speakers up to over 10,000 watts in the tweeter range--which they surely could not stand continuously.
As for resolution, well, I’ve read high end reviews for quite some years and I am aware of some of the kinds of things that are said. Just because an amplifier isn’t suitable for driving a very difficult load such as that of the Apogee Scintilla doesn’t mean it’s deficient for driving lots of other speakers. But I’ve seen reviewers try to extrapolate from the performance into a very difficult speaker load.
But let’s stick to the barking dog. I wonder just how far down that barking dog is? It would be interesting to measure for that could raise some interesting possibilities. I could conceive of scenarios having nothing to do with cables. You compared two expensive cables—how about some 12 or 14 gauge speaker cable from the hardware store? Would the barking dog still be audible?
As I understand it, you propose that dynamic drivers have enough resistance to moving that they are likely to muck up low level signals. Now, that at least is a testable hypothesis and perhaps you should test it. It should be measurable. If you want anecdotes, I can turn the Quad preamp down to its lowest level and I still get a lot of detail and stereo spread--actually with any of the main speakers I have had: the old Kef 104s, the Quad ESL-63s, the PSB Stratus Minis, and the Paradigm Signature S2s—that old Quad 606 is very clean at low levels. I don’t have the CD with the barking dog in the background so I can’t test this (I might not even be interested in the music).
I do wonder how a speaker can maintain the same audible character at extremely low levels without something happening to counter Fletcher-Munson effects. The Quad ESL-63, for example, isn’t linear in the bass at higher levels, that is, it starts limiting itself in the bass at more than moderate levels. So we get more relative bass at lower levels. The Kef 104 or 104aB is quite robust in the bass and laid back in the upper midrange, and it also played very nicely at very low levels.
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
"You don’t really know and that’s why I call it a black box methodology, although perhaps “plug and play” would be more appropriate. Plug and play is suitable for some types of problems, of course, like troubleshooting by a process of elimination.
"Well in this case that is probably what is needed because 1) In order to develop a model of how electrical signals propagate down a wire one needs an appropriate model. I guess the work of Malcolm Hawksford is a good place to start (although Jneutron might not agree). 2) I need detailed information on the metallurgy and design of the wires. This information I largely do not have.
So I can't really tell you mathematically what is going on with the wire, can I? I COULD maybe measure the signal loss at various frequencies through the wire, IF I had such an analyzer. If I was a serious cable manufacturer I would have such a thing. As I am not, I don't have one. Neither do most audiophiles. So since I can't really measure the cable I guess that is out of the question also.
I plug and play and use the analyzer between my ears. Its very sensitive and has the ability to be quite specific but it has problems with reliability and reproducibility, which is why it requires long term exposure to be certain of real effects vs. imaginary effects.
However; hearing a dog, that presummably was supposed to be on the recording and maybe wasn't heard by the engineer making the recording, and then not hearing the dog or that it flies below normal detection is something that is repeatable. It is also something clearly related to the passing of low amplitude signals.
As the only part of the chain that was changed, it seems obvious then that one can lay the blame at the cable. Plug and play or I prefer trial and error, is a perfectly valid way to test such a thing. Using a human detection system (ie. ears/brains) is a valid way to determine the audibility of such a thing and/or its relative realism.
""Dynamic" seems to mean different things to different people"
That's the problem, dynamic means one thing. If people use it incorrectly that's another issue. I expect you to use it correctly.
"Parenthetically, I think a driver is much more likely to heat up on steady signals than short transients"
I will try to find the sources but I don't think this is correct. A light bulb sure heats up and glows pretty darn quickly don't you think? A big surge of current will heat up a coil instantly but it will cool down only as function of the airflow and the coil materials.
"As for resolution, well, I’ve read high end reviews for quite some years and I am aware of some of the kinds of things that are said. Just because an amplifier isn’t suitable for driving a very difficult load such as that of the Apogee Scintilla doesn’t mean it’s deficient for driving lots of other speakers. But I’ve seen reviewers try to extrapolate from the performance into a very difficult speaker load."The Scintilla is a very special case because no other speaker is as brutal on an amp. Most of the amps that work without dying are not very good sounding as revealed by the brutal (in the resolution sense) Scintilla. So in effect it is a doubly brutal speaker. Amps that would sound good on it won't drive it and the amps that can drive it generally don't sound so good. We have now found some exceptions and a tube amp is in the works (really a 1 ohm tube amp!!).
"But let’s stick to the barking dog. I wonder just how far down that barking dog is?"Good question. I will be getting a copy of the cd soon. I hope I hear the dog on my system!!
"I could conceive of scenarios having nothing to do with cables. You compared two expensive cables—how about some 12 or 14 gauge speaker cable from the hardware store? Would the barking dog still be audible?"
Under the circumstances of this test I don't know how it could have been anything else. They were the only variables changed in the test (the first test where they heard the sound in both but greatly diminshed in one vs. the other cable). The other system could have multiple explanations (like cd player, preamp, amp, speaker's internal wiring, ambient noise). Sure they could add cheap 12 gauge wire to the test next time, why not. Maybe the dog is MORE audible! I for one am not a proponent that cables need to be expensive to be good (I personally don't have expensive cables).
"I do wonder how a speaker can maintain the same audible character at extremely low levels without something happening to counter Fletcher-Munson effects."
It doesn't matter because your brain already knows what things SHOULD sound like at low levels. Fletcher-Munson works with real sounds as well. The change heard with speakers at low levels is ON TOP of the usual changes in how you hear with level. Loudness curves on stereos in the past were to combat the problem with the stereo systems behavior not your hearing mechanisms behavior. So a stereo system that maintains the correct response, FR wise and dynamically will sound natural because the instruments sounded more or less that way live and that is what you are used to hearing from real sounds.
"The Quad ESL-63, for example, isn’t linear in the bass at higher levels, that is, it starts limiting itself in the bass at more than moderate levels. So we get more relative bass at lower levels"
This is a dynamic range limitation of the Quad-63 and means that the speaker is probably more correctly balanced from low to middle volumes. This is true for a lot of electrostatic speakers. However; some have a much higher range upward while maintaining the downward range (Soundlabs and Acoustats come to mind here) because of their nearly massless drivers.
"The Kef 104 or 104aB is quite robust in the bass and laid back in the upper midrange"
Then it likely had a dip in the FR through the presence region, which once corrected with equalization, it would no longer sound so laid back. OR it has some dynamic constriction at the top of the coaxial midranges passband or some funny breakup modes? How good is its balance at low levels compared to a top electrostatic speaker? That is the question.
The old Kef 104 was pretty flat in the listening window but with the 8" woofer crossed over to a 3/4 tweeter at 3 kHz the off axis response suffered between about 1000 and 2500 Hz, which would affect the total power response. You can't really fix that with an equalizer, though it can help things to a degree, as it won't improve the dispersion. It was quite a good speaker in the right set up, but not really room friendly. Compared with the Quad ESL-63, it really didn't sound bad at all, but not as detailed.The ear is less sensitive to both low frequencies and high frequencies. This has nothing to do with the deficiencies of stereo systems. It's easy to look up on the net.
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
"The ear is less sensitive to both low frequencies and high frequencies. This has nothing to do with the deficiencies of stereo systems. It's easy to look up on the net."THat's my point! In real life with real live instruments your hear sensitivity also drops at high and low frequencies with decreasing level. When we hear the highs and lows dropping out with a stereo at low levels its because there is EXCESS loss over and above our normal lack of sensitivity in these ranges. THis loss is coming from the stereo itself. If it were to maintain the same FR and dynamic envelope at 50db as it has at 80 db then the softness would sound natural as when an instrument gets softer from 80 to 50db. Since most stereos don't sound natural at low levels this is a clear indicator of excess loss from the stereo not because of the change in hearing sensitivity. Loudness contours were designed to overcome the limitations of the gear not the listener. Your brain knows what sounds natural at low levels and so the hearing curve is irrelevant for live sounds. If the response of the stereo system is constant regardless of level then the sounds on the recordings will soften in a natural sounding way but most systems are not constant thus the loss of realism at low levels (and high levels).
Well, just from a layperson's point of view, I think it's a little more complicated than that. First of all, we have your idea of "natural" sound, which has not been verified. Second, in real life, sounds farther off are often softer but have more reflected sound. Third, turning the volume down often makes the stereo image seem to move back some. Fourth, like it or not, at lower volumes, the ear is less sensitive to low and high frequencies.Many posters here besides my self have suggested that speakers which sound good at low volumes tend to approximate the Fletcher-Munson curves (or someone else's equal loudness curve).
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
"First of all, we have your idea of "natural" sound, which has not been verified"True and the same can be said for when you say your system sounds fine as well. However; are you a regular goer of live classical and/or other music that is unamplified? Are you a musician or have you lived with someone who is a professional musician? Do you now or have you ever been involved in the making of recordings in natural spaces (ie. a concert hall)? If you answer yes to these then I perhaps we are coming from the same background.
"Second, in real life, sounds farther off are often softer but have more reflected sound."
Yes this is correct; however, we are discussing the systems effects on sounds that were recorded from farther away or that are soft but close. You don't want the system to impose the same effect as a live sound from far away. It is like a double negative, its a no no!
"Third, turning the volume down often makes the stereo image seem to move back some."
Why should this be? Is this simply your observation in your system or do you have some physical explanation? If the system is properly preserving the harmonic content of the instruments when you decrease the volume then it shouldn't happen. With a real instrument, like a sax or trumpet, the sound recedes more inside the instrument at lower volumes than when it is played full blast. This has a lot to do with how the harmonic content of the instrument changes with the volume level its played at.
If I understand you correctly you are saying that a loud trumpet (as it is on the recording) played back softly (as in the volume control turned down) will sound farther away than it would if the volume control was set to give a realistic SPL level. IMO, this is a clear sign that your system has a different set of harmonic components that it adds at the low level vs. the high level or the speakers FR balance is different at low spl level vs. high spl level. Either way this would seem to indicate a problem with that system. I don't disagree that this receding of the sound with decreasing level could happen just that it should not happen.
"Fourth, like it or not, at lower volumes, the ear is less sensitive to low and high frequencies."
No one is disputing this. However; the microphone doesn't suffer from this problem, which means that soft sounds are captured with close to the original harmonic content and freqeuency balance. The reproduction will then sound natural (ie. you will hear the same content on the recording that you would have heard live if you were there) IF the system is not further altering the harmonic content and FR with level. If it is, namely losing bass and HF response at low levels, then the sound will lose life at low levels and no longer sound realistic. As long as these are preserved at low levels it will sound like a natural softening not the usual lifelessness most systems exhibit.
For example, whenever a reviewer says a speaker needs some juice to "wake up" this is a clear sign to me that this speaker cannot perform naturally with low level signals, this means either when played at low volumes or when there are soft sounds (like ambient information) in the louder matrix of the music.
"Many posters here besides my self have suggested that speakers which sound good at low volumes tend to approximate the Fletcher-Munson curves (or someone else's equal loudness curve)."
Maybe they are purposely designed this way to compensate for the losses that typical speakers show at low levels (the losses are always there just more noticeable at low levels where the percentage of error is larger). However; now this speaker will not sound correct at higher volumes because the bass and treble are tipped up. Manipulating frequency response is not really the answer to what is really a loss of dynamics. The only way I can think to do this in the frequency domain is with DSP where the DSP monitors the current to drivers and then applies a sliding scale equalization curve dependent on the signal level. It can be fast enough but I don't know anyone making a level dependent equalizer. Maybe a bright idea though.
It is the same problem with Class AB amps. They have zero crossing distortion that makes itself most known at low levels and is a major reason why these amps don't sound good at low levels because the distortion to signal ratio is much greater than at full power. The zero distoriton is always the same in absolute level terms.
Of course, my idea of natural sound has not been verified, either.Musician? Well, I've been a choral singer most of my life and have been capable of baritone solos for some decades. I've done some recordings. Just heard the dress rehearsal for Messiah last night (I have laryngitis, so couldn't participate). Maybe I'll be able to do some of the performances . . .
Yep. Speaker with a depressed midrange will sound that way played louder too, but that can be quite pleasant on a lot of material. But it doesn't prevent them from sounding great at low levels.
Walking away from a live performance is not the same as turning the volume down.
You'd better look at those equal loudness curves again. Sensitivity in the bass drops quite a bit as the level goes down.
When you get around to measuring the behavior of speakers at low levels I'll give your theories more credence. Perception of the distance of the sound source seems to be a controverted area with natural sounds and the sound image from a stereo system lacks many of the clues we can have with natural sounds.
Oh, I just looked on the Stereophile site and there is an interesting article by Keith Howard on voice coil heating and changes in impedance. He thinks it's likely to be a negligible factor in normal listening.
http://www.stereophile.com/reference/1106hot/
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"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
http://www.rythmikaudio.com/servo_tech.htm
http://www.jblpro.com/pages/general_faq.htm#What is "power compression"?
http://www.nearfieldacoustics.com/whiteppr.pdf (read the section on dynamics where they state that even small compression effects in the bass can have big effects on perceived loudness).
http://www.klippel.de/download/bin\AN12 - Amplitude Compression.pdf"Don’t Make a Bad First “Compression”
All these SPL ratings are 1w/1m ratings. “But what type of performance can I expect if I apply more than 1w of input electrical power to my subwoofer?”Well, it’s quite simple: you suffer from compression. There are two types of compression to be concerned with:
1. Thermal/Power
2. BLAs electrical power is applied to a voice coil, the voice coil heats up. This causes an increase in the Resistance of the voice coil, also known as Re. This is referred to as thermal or power compression.
As the voice coil moves out of the gap, motor strength (also known as BL) begins to drop. The further the voice coil moves out of the gap, the lower BL drops. As BL decreases, output drops as well. A 30% decrease in BL will cause a 3dB decrease in acoustical output.
Now which is worse? I guess you could say that depends. Thermal/Power compression is typically a slower process. Because music is very dynamic, it does take a few seconds for the voice coil to increase in heat, and therefore, a few seconds for the voice coil’s resistance to increase. Once this voice coil is hot, it takes 10-30 seconds to cool back down. As you can see, once the voice coil has become hot, the effects of Thermal/Power compression are fairly constant.
On the other hand, BL compression is a "quicker" issue. A voice coil can move right out of the gap and back into the gap in a single second. As excursion increases, it only gets worse. It is quite obvious that BL compression is the more serious issue of the two.
Don’t Make a Bad First “Compression”
All these SPL ratings are 1w/1m ratings. “But what type of performance can I expect if I apply more than 1w of input electrical power to my subwoofer?”Well, it’s quite simple: you suffer from compression. There are two types of compression to be concerned with:
1. Thermal/Power
2. BLAs electrical power is applied to a voice coil, the voice coil heats up. This causes an increase in the Resistance of the voice coil, also known as Re. This is referred to as thermal or power compression.
As the voice coil moves out of the gap, motor strength (also known as BL) begins to drop. The further the voice coil moves out of the gap, the lower BL drops. As BL decreases, output drops as well. A 30% decrease in BL will cause a 3dB decrease in acoustical output.
Now which is worse? I guess you could say that depends. Thermal/Power compression is typically a slower process. Because music is very dynamic, it does take a few seconds for the voice coil to increase in heat, and therefore, a few seconds for the voice coil’s resistance to increase. Once this voice coil is hot, it takes 10-30 seconds to cool back down. As you can see, once the voice coil has become hot, the effects of Thermal/Power compression are fairly constant.
On the other hand, BL compression is a "quicker" issue. A voice coil can move right out of the gap and back into the gap in a single second. As excursion increases, it only gets worse. It is quite obvious that BL compression is the more serious issue of the two."
A well designed voice coil system shouldn't move out of the gap unless very long excursions are happening so thermal is the bigger problem at realistic volume levels.
Almost every speaker maker in audio is concerned with the effects and not many mention FR at all. Could it be because compression affects realism in sound more than FR abberations, perhaps?
"Yep. Speaker with a depressed midrange will sound that way played louder too, but that can be quite pleasant on a lot of material. But it doesn't prevent them from sounding great at low levels."I disagree, a depressed midrange most certainly affects things from sounding correct at any level. Speech intelligibility for one thing suffers. I have heard this with a number of speakers that have a dip in the presence region. Also, when the level gets lower that 3-5 db or so dip may now drop the response in that region below the level where the speaker performs correctly thus further reducing the clarity of sounds in that frequency range.
"You'd better look at those equal loudness curves again. Sensitivity in the bass drops quite a bit as the level goes down"Not sure what point you are trying to make here. It would be helpful if you completed the full thought rather than give a one liner and expect me to interpret what you mean. I try to be as explicit as possible so as not to be misunderstood. I frankly have now idea what you want to make of this obvious factoid. It seems like a non-sequitor.
"Oh, I just looked on the Stereophile site and there is an interesting article by Keith Howard on voice coil heating and changes in impedance. He thinks it's likely to be a negligible factor in normal listening."
I read this but I question his methodology a bit. Here is another test done with small hifi and pro monitors (not very different from the kind of speaker Howard used) and they show quite demonstrable differences in the performance due to thermal compression.
http://www.soundonsound.com/sos/jul02/articles/monitors2.asp
If you do, the least of your worries is thermal compression.
____________________________________________________________
"Nature loves to hide."
---Heraclitus of Ephesus (trans. Wheelwright)
No the average levels are that loud but the peaks could be because I often listen to wide dynamic range recordings (like 20+ db over the average level). So if it takes only a few ms to heat the coil up (one large peak) and 10-30 sec to cool it down then it is clear that thermal compression can be a problem for the music following the peak(s). The point is that the response of the system is not constant but instead constantly changing subtly. This can affect imaging stability also (for instance if the woofer in the left speaker has sublty different dynamic behavior than the right speaker woofer).
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