Bentoronto: No, my interpretation of an F-M relation is quite straight forward. It is a psychophysical relation, as simple as that. Actually, I was a bit surprised by your comment, since you seemed better versed on this general topic compared to most folks.
The loudness control is needed because we often don't listen at the same level as the tracks were mixed and mastered at. Even if there were a standard - and there certainly isn't - we still might like to listen softer. That's going to change the overall tonal balance. That's how the F/M curves work.
As for recording to recording, I don't find that it matters that much. Sure, each recording has its own tonal balance, but if my system is tuned too bright, almost everything sounds too bright. Too dark (like now) and everything sounds too dark. It's not that the recordings all sound alike, but I hear an overall skew to everything.
I can walk into a room with a system that I've never heard before and almost immediately get a sense of the tonal balance - unless it's a really weird recording. I think most of us can do that, right?
As for recording to recording, I don't find that it matters that much. Sure, each recording has its own tonal balance, but if my system is tuned too bright, almost everything sounds too bright. Too dark (like now) and everything sounds too dark. It's not that the recordings all sound alike, but I hear an overall skew to everything.
I can walk into a room with a system that I've never heard before and almost immediately get a sense of the tonal balance - unless it's a really weird recording. I think most of us can do that, right?
I'm unconvinced that loudness compensation makes for a sonic improvment. When content in the midband is low in level, wouldn't the ear/brain have an expectation for the appropriate (perceptually lower) balance for bass/upper-treble in relation? The equal loudness curves are based on absolute level, so adjusting the balance based on spl decouples it from the absolute level, potentially making a quite unnatural sounding effect. Maybe to the brain: "A sound that quiet with that much bass sounds weird."
That's a very interesting question and I've been pondering it for some months.
Today, my opinion is something like the following. When you look at a photo print, the people look 3 inches tall and also 6 feet tall. To look 6 feet tall, your mind is assuming a certain viewing distance. Vision gives you various applicable cues for doing so.
Does that relate to hearing loudness levels? I believe it does but there are subtleties akin to the cue that mountains look blue in the distance.
The analysis in vision is well understood and often geometrically self-evident. The analysis for hearing isn't well understood. If it were better understood, there would be important implications for music recording and reproduction.
Yep. But there's an "in between" somewhere where it sounds a bit better without getting too unnatural. Maybe. OK for "background music", which isn't expected to sound great anyway. Maybe.
In fact, that initial impression is always the most vivid. As you sit and listen you get used to the sound and the balance aberations seem to fade.
This is a standard perceptual phonomenon. As a kid a remember having sunglasses with dark green lenses. After wearing them for a half an hour you could take them off and marvel at how oddly pink the world was. You had gotten used to the unnatural color. This is part of photography also. We have to adjust color balance for various lighting conditions (tungsten, flourescent, sunlight, skylight) but we don't really see the difference by eye since we are immersed in that lighting environment with time to get used to it.
I've noticed it at wine tastings too, where the first sip of a new wine is always most notable. By the third or fourth the initially dramatic difference has faded.
I think this is a big part of "break in". People get used to the sound of a system over time and assume that it is changing through some break in process.
David S.
I think this is also why some systems need to be played loud to "come alive" and others sound good at low level. They have a little built in positive or negative loudness control.
David S.
Precisely why I like having an active subwoofer with a separate volume control to make it easy to adjust the best for overall level setting, recordings engineered with lower bass content and, yes, for my preference for slightly stronger bass at times. Small changes improve it as I perceive it. I don't change anything else, only the bass setting. Sometimes it even means lowering the bass setting. 😉
Heretical, I know, but I listen to music to enjoy it and if tweaking the bass sounds better to me, that's what I do. I'm not into trying to perfectly re-create what some recording engineer heard.
Dave
Ha! I had not really thought about that directly. Funny. It's got to be something we learn. But we must learn it very young
They do, yes they do.
So here is my story:
There is a restaurant downtown where you can sit outside on the rather large patio to eat. I remember going there once recently and hearing the little outdoor speakers that they have all around for background music (Mototown hits and such). Ugg! Awful! Terrible tonal balance, all nasally mids and lumpy response - almost unbearable. I commented to my wife how awful they were, she didn't seem to notice.
But by the time we left they sounded rather good. So much of a change that I almost asked the waiter if they had done something to the system settings. But I knew better. The change was brought not be the hand of an employee, but by the hand of time - and beer.
dlr is adjusting for F-M. Simple as that except... there is an interesting implication. People should consider the F-M (or more correct later curves) inflection points when choosing their sub-woofer crossover point.
Logical?
About the other home-spun engineers-eye-views of perception, some comments are perceptive some not but I don't have the patience to fuss about it now. Think in terms of "cues" and the perceptions they lead to in your mind. Adaptation (and negative after-effects) are widely present and in all kinds of ways in the senses; similar to that is what I earlier I called it "AC coupled" and you'll find that a pretty applicable metaphor for other phenomena.
I do think we are seeing, at last, a victory for the view that NOBODY can "think" themselves out of normal human perceptual influences in hearing, any more than they can see the "real" color of a shirt in neon light no matter how hard they apply their expertise to the effort.
Logical?
About the other home-spun engineers-eye-views of perception, some comments are perceptive some not but I don't have the patience to fuss about it now. Think in terms of "cues" and the perceptions they lead to in your mind. Adaptation (and negative after-effects) are widely present and in all kinds of ways in the senses; similar to that is what I earlier I called it "AC coupled" and you'll find that a pretty applicable metaphor for other phenomena.
I do think we are seeing, at last, a victory for the view that NOBODY can "think" themselves out of normal human perceptual influences in hearing, any more than they can see the "real" color of a shirt in neon light no matter how hard they apply their expertise to the effort.
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Thank you very much for the final compliment. So do you believe there is hope I can rise to your level of understanding of these principles?
I could be wrong here, but I love what has been said here. Apparently most people believe that there is such thing as a break-in period, and your tube amplifier just won't sound right before that is done. Yet I've never heard, or been able to imagine why that would be, from any kind of technical point of view. I totally agree that the ear-brain mechanism will get surprisingly used to significant anomolies in frequency response, especially if the changes are gradual. The same people are sure that any tone control is evil. Once they've dropped $4000 on a preamp that has only input selector and volume, it seems that their ego's won't let them believe anything else.
Or maybe, just maybe, an actual "break in" process does in fact occur, and if one's system is of sufficient resolution one can indeed hear that process occurring. 😉
I did not mean to sound condescending and I am sorry you took it that way.
In my defense, I am used to discussing these kinds of topics (psychophysical relations) with other researchers. So I normally assume others have a common background and terminology. Consequently I was confused by why you "understood" the F-M curves as being something different. My mistake and the topic is probably best closed at this point.
The bigger picture
For many decades I've been researching, designing and building speaker systems, and preamps, poweramps, I re-optimized the Carver Holographic generator, etc. etc. Every time I "calibrated" the speakers to measure flat with pink noise, I noticed that they sounded cold and thin. Usually a bit brassy too. When I was working at Dolby Labs I borrowed some great equipment and did a bunch of recordings of acoustic musicians, and learned how tricky the recording process is. It is never any variation of perfect. In recording studios they process most recordings with whatever (reverbs, compressors, de-essers, tone controls, etc.) to try to make up for what wasn't able to be right in the recording process. I've also looked closely at, and understood the theory behind listening room acoustics, and how that colors what a speaker puts out. There are many many many reasons why tone control is a good thing (when it's done right, and it often isn't). I consider it very foolish to pretend that you have more "fidelity" with no tone controls in your system. I default in the direction of high fidelity, and from there, I do what it takes to make it sound real good, whatever that may be. The biggest problem with "Loudness Comp" is that it's never adjustable enough. I'm developing a version that hopefully is. Four section, all passive with 6SL/SN7's making up for gain loss in the passive (James) tone sections. I've already done it with opamps and lived with it for decades, and know I like it. Now I'm going to do it with tubes, no neg feedback anywhere. Don't let the Hi-Fi marketeers make a fool of you by convincing you that you don't ever want to mess with tone... 🙁
For many decades I've been researching, designing and building speaker systems, and preamps, poweramps, I re-optimized the Carver Holographic generator, etc. etc. Every time I "calibrated" the speakers to measure flat with pink noise, I noticed that they sounded cold and thin. Usually a bit brassy too. When I was working at Dolby Labs I borrowed some great equipment and did a bunch of recordings of acoustic musicians, and learned how tricky the recording process is. It is never any variation of perfect. In recording studios they process most recordings with whatever (reverbs, compressors, de-essers, tone controls, etc.) to try to make up for what wasn't able to be right in the recording process. I've also looked closely at, and understood the theory behind listening room acoustics, and how that colors what a speaker puts out. There are many many many reasons why tone control is a good thing (when it's done right, and it often isn't). I consider it very foolish to pretend that you have more "fidelity" with no tone controls in your system. I default in the direction of high fidelity, and from there, I do what it takes to make it sound real good, whatever that may be. The biggest problem with "Loudness Comp" is that it's never adjustable enough. I'm developing a version that hopefully is. Four section, all passive with 6SL/SN7's making up for gain loss in the passive (James) tone sections. I've already done it with opamps and lived with it for decades, and know I like it. Now I'm going to do it with tubes, no neg feedback anywhere. Don't let the Hi-Fi marketeers make a fool of you by convincing you that you don't ever want to mess with tone... 🙁
I've been at this for awhile and I've never heard anyone opine that a tone control is "evil", so I don't know why that misrepresentation is being brought into the discussion, but common sense would tell you that in a system of sufficient resolution, anything added to a circuit, such as tone controls, will have at least some detrimental effect on resolution.
The low resolving mid-fi systems that I have owned have such glaring faults in their frequency responses that they require large corrections in order to make them listenable, and for those types of systems tone controls are welcome.
The higher resolving higher-end systems that I have owned need very little in the way of tonal compensation, and although perhaps tone controls would indeed make the necessary corrections, there is no free lunch, and the trade-off would be that the extra circuitry and the tone controls themselves would hamper resolution. For that reason many prefer to make tonal corrections in their high-end systems with the components themselves, or with cabling, or with room treatments, and contrary to the poster's incorrect assertion, ego has nothing to do with it.
Maybe I shouldn't have worded it that way. The art of producing and re-producing music is all about tone, right from the start. Ask any musician. Pretending that a system that measures perfectly flat is like selling out to peer pressure rather than getting truly educated and thinking for yourself. When it sounds good, it is good. If a change in tone makes it more pleasant to you, in the acoustics of your listening room, then isn't that better?
In nearly all cases I would agree that the commonly claimed "break-in" period for speakers is actually a psychoacoustic phenomenon and not reflected by any actual changes in measurements, and that it is as others have already suggested your own brain adapting to the characteristic sound of the system.
The brain (and/or hearing system) does indeed seem to have a remarkable capacity to adjust your perception of frequency balance so that after a period of time listening to an unbalanced spectra, the error is gradually equalized.
Think of a spectrum analyser (the brain) analysing the spectra that it listens to, and gradually (over hours, days, weeks) "tweaking" it's own built in equalizer to get what it perceives to be a natural representation of familiar sounds.
The louder and/or more frequently you listen to music, (to a point) the faster corrections are made to bring the sound "into line", by skewing your built in equalizer. After a period of some days or weeks with only "natural" sound sources being listened to, the brain gradually "unlearns" this artificial correction curve, and "recalibrates" to natural sounds.
The more severe the tonal imbalance of the speaker, the harder the brain has to work to adjust itself so that things sound "right", and I think that is one of the contributing factors towards listener fatigue - a speaker (and/or recording!) that is as close as possible to a natural frequency balance in the listening environment will provide minimum listener fatigue, since the brain has hardly any adjusting to do going from "natural" to recorded sounds.
In this case it will "sound right" on first listen, which is a good sign a speaker is probably well balanced. Any speaker that sounds much better after prolonged listening is usually a sign that the speaker is in fact unbalanced in it's response.
Provided that your perception is not already "skewed" by quite recently listening to another set of speakers with their own unique imbalances, the "first impression" of a speaker is usually the correct one, at least in terms of frequency balance.
If it sounded lean on bass on first listen but later sounds better, it didn't "break-in", it is in fact lean on bass, it's just your brain got used to it 😉
This is a big problem for anyone auditioning or designing speakers if they are not aware of this issue, and place too much faith in "ears only" evaluation of speakers that they spend a lot of time listening to, as the effect seems to be cumulative with exposure, so with enough listening to your own speakers especially at higher volumes, some quite serious errors in balance start to sound normal, and with no frame of reference you can be shooting in the dark trying to figure out what's wrong or make adjustments.
You can hear even small introduced changes in relative frequency balance but you have no idea what the baseline reference is, or what constitutes flat unless you have some sort of reference, like a very neutral speaker to compare with, or some live music.
Why does the brain do this ? I think it's probably just a mechanism that is designed to adapt to (a) each persons unique ears, as no two people have the same shaped ears, and internal structures and sensitivities will be different as well - so the brain just "learns" the characteristic of your own ears as you grow up, and (b) changes with your ears as you age and lose sensitivity at different frequencies, get wax in your ears, hair covering your ears etc.
The compensation works so well that by the time you start to notice loss in hearing with age the threshold sensitivity in the treble can be 10dB or more down on what it was - and yet at normal listening levels the treble in music sounds normal, because the brain has cranked up the perceptual treble controls, but when the hearing threshold at low levels is tested, it's well down.
As for potential causes of actual "speaker break-in", the one most often claimed is changes in compliance of a woofer with use over a period of months affecting the bass, but if you measure a woofer you'll find that the compliance softens significantly in just a few seconds of use, and stiffens back up again within seconds or certainly no more than a minute or so. There is a significant change, but it's not a permanent or progressive change.
About the only thing I've ever come across that could be close to a "break-in" effect is moisture content of some types of paper cone drivers.
Some large (>= 8") paper cone full range drivers seem to be a bit sensitive to changes in relative humidity. Since paper is Hygroscopic the amount of moisture in the cone is affected by humidity. With many drivers this wouldn't be a big deal but in a driver that is operating in cone breakup mode over 2-3 octaves where breakup resonances are very delicately damped and controlled, even small changes in the mass, stiffness, and losses of the paper can alter the characteristic resonances in a way that can be measured and heard.
It was particularly noticeable to me living in New Zealand where the humidity can vary dramatically in summer from below 30% to over 90% within the space of a few weeks. I was able to measure some small changes in the response of the drivers that correlated with humidity, and could hear changes as well. Since I moved to the UK where the (indoor) humidity is much lower and more uniform, I haven't noticed the same changes.
Perhaps one possible cause of actual "break-in" is a newly shipped and opened speaker (coming from a different part of the country or even a different country) being subject to local humidity conditions, and taking a while for the moisture content of it's cones to stabilize in the local climate conditions.
Of course that would only apply to cones which are Hygroscopic, like un-coated paper, materials such as kevlar and polypropylene would be unaffected. It would also only have an effect in the cone breakup region, so would be unlikely to have an audible effect on a multi-way design unless the drivers were crossed over a long way above their cone breakup frequencies.
Just throwing it out there as a thought anyway 🙂
You wrote all that just to say "breaking in speakers doesn't work unless you're LISTENING to them" ??? 🙂
But to middle portion of your post, yes there seems to be a lot of mechanisms that the ear-and-mind use to distinguish "the sound" of something versus the many natural things that can affect its sound - as an example. a human voice speaking directly at you vs. speaking away from you which diminishes the high frequencies, diffraction around walls does similar things with frequency response, echoes off walls, position in relation to your head (HRTF), etc.
I forget if this was mentioned, but it would be interesting to actually test speaker break-in, a pair that someone has been listening to for a year versus one fresh off the assembly line. But (and I've seen this on another forum as well as here) too few people who notice these things are interested in finding out what causes them - things such as break-in are accepted as a part of life without question.
But to middle portion of your post, yes there seems to be a lot of mechanisms that the ear-and-mind use to distinguish "the sound" of something versus the many natural things that can affect its sound - as an example. a human voice speaking directly at you vs. speaking away from you which diminishes the high frequencies, diffraction around walls does similar things with frequency response, echoes off walls, position in relation to your head (HRTF), etc.
I forget if this was mentioned, but it would be interesting to actually test speaker break-in, a pair that someone has been listening to for a year versus one fresh off the assembly line. But (and I've seen this on another forum as well as here) too few people who notice these things are interested in finding out what causes them - things such as break-in are accepted as a part of life without question.
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