Low frequency matters a LOT
an example would be comparing two subs both rated for 20hz operation in 1.25 cu ft sealed box.
1st sub played lows fairly ok, but was much louder in the upper bass
2nd sub played MUCH better down at the real lows, as was not so much louder in the upper bass. Also bass drums in rock music were way more clear and audible, and realistic with this sub. Also more low notes were audible in the bass notes of rap. I don't know about you, but I sure can HEAR the difference with lower lows.
That's two subs that supposed to play 20 hz, but one played way better.
I can really tell the difference when the lowest lows are played well from the music. Also, to really ENJOY my music, I have to FEEL the BASS!
an example would be comparing two subs both rated for 20hz operation in 1.25 cu ft sealed box.
1st sub played lows fairly ok, but was much louder in the upper bass
2nd sub played MUCH better down at the real lows, as was not so much louder in the upper bass. Also bass drums in rock music were way more clear and audible, and realistic with this sub. Also more low notes were audible in the bass notes of rap. I don't know about you, but I sure can HEAR the difference with lower lows.
That's two subs that supposed to play 20 hz, but one played way better.
I can really tell the difference when the lowest lows are played well from the music. Also, to really ENJOY my music, I have to FEEL the BASS!
When a kick drum pounds at your chest and you feel it, thats not 20hz, thats between 40-60hz, if we are talking music there is very little going on below 30hz. As far as the bass notes in rap, not even close to 20hz. Granted the second sub may have played down to 20hz better than the first, but that's is not what you enjoyed about it, and this my point. I don't believe many people know what 20hz is, or sounds like.
-Justin
[edit] I just wanted to say that I am not saying that low frequency doesn't matter, but rather that many people argue about the wrong thing when it comes to low frequency reproduction. I'm all for going down to 20hz, but only if you can do so without sacrificing frequency response in the areas where most the music information is reproduced.
-Justin
[edit] I just wanted to say that I am not saying that low frequency doesn't matter, but rather that many people argue about the wrong thing when it comes to low frequency reproduction. I'm all for going down to 20hz, but only if you can do so without sacrificing frequency response in the areas where most the music information is reproduced.
Low bass is more of a novelty, and it's kind of cool to try it out. I've heard 20Hz test tones on concert set ups, and it's not really that enjoyable, you can't really dance to it. That feel your pants vibrating against your legs is around 50Hz, and the bass that really gets people dancing is 40Hz - 80Hz. Maybe even 55Hz - 75Hz if you want to narrow it down. You should not sacrifice SPL in this range for more extension.
Movies are probably a little different, but that tone the theatres play to show off their subwoofers is around 45Hz, judging by ear anyways.
Movies are probably a little different, but that tone the theatres play to show off their subwoofers is around 45Hz, judging by ear anyways.
despotic931 said:
I know.
While playing around a while back with a Term Lab pressure sensor, my pair of XXX 18s in EBS alignments being driven by 5KW measured over 125db @20Hz..... And honestly, I'm not sure what I heard easier, the 20Hz sine wave or all the air moving around the room.... It is really, really hard to hear those low frequencies... Even when they are very loud....
ßart West-VL. said:
Agreed, I hear people arguing against the necessity for supertweeters (and admittedly, with CD, they're not contributing much) because "I can't hear that high". You can SENSE that high. Human perception and human conscious perception are very different things. It's something that separates us from the animals, we perceive things we're not aware of, because we have such a developed mental construct between perception and our consciousness, whereas there's not that buffer in the animal world. Observing human behavior with unknown stimulii removes this barrier to some extent, we can see that certain things (including frequencies above and below 20-20k) affect humans, even when they're not aware of it.
One of the best ways to pick gear is to rely upon your behavioral response. I use that as an evaluation criterion for things I'm working with. Does it make me want to listen to music more often in the medium/long term? If so, euphonic or not, it's a plus and I'll continue on that path.
We're not machines, and our perceptive mechanisms are very complex, with many intertwining aspects. Who'd have thunk that a speaker type that leaves the back open to come back at you off the back wall (dipoles) would have LESS audible coloration from the backwave than something with a closed box behind it? But the nature of our perception makes the timing of these reflections critical, more critical than their amplitude response.
Ultimately, our highly developed mechanisms don't follow simple testing as accurately as do other test subjects, and there's never going to be a full understanding there, so there's always going to be an area where perception and 'scientific reality' collide.
Perception vs. reality in vision
We are different, but ...
No, "we" (at least I) can't. I've got OK high freq response for my years, and have done many, many ABX tests (with or without strong, but linear phase, low pass filters at 18kHz). Nothing! Response drops like a stone around 17.7kHz (41 years). (Motto: If you can't ABX it you are probably fooling yourself.)
But things are very different at the low end, where I can "feel" pressure that I can't "hear" as a tone, so I'm not arguing all that much - our perception is complicated.
It is unimportant to have headroom (perhaps messing up the phase is a bad idea; good phase can be achieved without headroom, with some DSP).
I'm not so sure about the more on-topic: "footroom", but somewhere around 20 Hz the levels required to do anything much audibly also start to crack plaster (in my wood frame house, at least). (I can reproduce 16 Hz at reasonable levels as measured by a microphone, but it does not sound very impressive, as there is some 2nd harmonic which is all I "hear".)
The trick is not so much to produce <20Hz, but to do so with low enough distortion that the distortion products are quieter than the fundamental (when it is loud enough to make a difference). It is not easy!
Ken
edit: typo
badman said:
No, "we" (at least I) can't. I've got OK high freq response for my years, and have done many, many ABX tests (with or without strong, but linear phase, low pass filters at 18kHz). Nothing! Response drops like a stone around 17.7kHz (41 years). (Motto: If you can't ABX it you are probably fooling yourself.)
But things are very different at the low end, where I can "feel" pressure that I can't "hear" as a tone, so I'm not arguing all that much - our perception is complicated.
It is unimportant to have headroom (perhaps messing up the phase is a bad idea; good phase can be achieved without headroom, with some DSP).
I'm not so sure about the more on-topic: "footroom", but somewhere around 20 Hz the levels required to do anything much audibly also start to crack plaster (in my wood frame house, at least). (I can reproduce 16 Hz at reasonable levels as measured by a microphone, but it does not sound very impressive, as there is some 2nd harmonic which is all I "hear".)
The trick is not so much to produce <20Hz, but to do so with low enough distortion that the distortion products are quieter than the fundamental (when it is loud enough to make a difference). It is not easy!
Ken
edit: typo
I'm pretty much in agreement with kstrain's views.
Pity people like badman post great 10 foot high steaming piles of amateur psychobabble confusion. I say "amateur" since I have been practicing human factors psychology for a long time and lots of psychology is of great value here. But then, it would be wrong of me to criticize without providing details. So pretend I didn't say that.
When you say "can't hear..." or "didn't notice....," you are relating to some means of measurement and/criteria of performance, often a convention. Sometimes you can't hear something as assessed by one means of measurement or criterion, but you can hear it if assessed by other means or different criteria. Obviously, you can detect and react to frequencies that are loud enough to shake your sternum or cause the wax to drip from your ears.
Engineering Psychologists tend to be skeptical of people who say, "Well, you can't tell me if I switch the supertweeter on and off a few times in an A-B comparison with a glockenspiel recording, but it still has some kind of wonnerful effect on my music pleasure." (I won't be more authoritarian than to say "skeptical" because even plain A-B tests can be faulty.)
That's just silly old-fashioned golden-ear talk.
BTW, the interesting history of thinking about harmonic and IM distortion decades ago is fascinating and an object lesson for both those who say "the ears are right" and those who say "the meter is right."
Pity people like badman post great 10 foot high steaming piles of amateur psychobabble confusion. I say "amateur" since I have been practicing human factors psychology for a long time and lots of psychology is of great value here. But then, it would be wrong of me to criticize without providing details. So pretend I didn't say that.
When you say "can't hear..." or "didn't notice....," you are relating to some means of measurement and/criteria of performance, often a convention. Sometimes you can't hear something as assessed by one means of measurement or criterion, but you can hear it if assessed by other means or different criteria. Obviously, you can detect and react to frequencies that are loud enough to shake your sternum or cause the wax to drip from your ears.
Engineering Psychologists tend to be skeptical of people who say, "Well, you can't tell me if I switch the supertweeter on and off a few times in an A-B comparison with a glockenspiel recording, but it still has some kind of wonnerful effect on my music pleasure." (I won't be more authoritarian than to say "skeptical" because even plain A-B tests can be faulty.)
That's just silly old-fashioned golden-ear talk.
BTW, the interesting history of thinking about harmonic and IM distortion decades ago is fascinating and an object lesson for both those who say "the ears are right" and those who say "the meter is right."
Re: We are different, but ...
But those are all conscious perception tests, and I'm not particularly impressed with efficacy of ABX. But we agree on most points, and I appreciate the effort to stay on topic and be cordial despite disagreement.
Well, let me start with an objection to your characterizing my comments as "great 10 foot high steaming piles of amateur psychobabble confusion", you can disagree without implying that the person you're disagreeing with is confused, amateurish, and full of.. whatever. Not the way to get a good conversation going.
Frankly, I don't care what you've practiced and for how long. Expertise is not a legitimate argument. And "So pretend I didn't say that." is a ludicrous attempt at an 'out' for your rude and presumptuous preceding paragraph.
Who said anything about high enough levels of playback to shake the sternum or make wax drip from your ears?
I suggest you take the time to review audiology a little bit, the Bell Labs research was pretty weak, and that's where 20-20k guideline you seem to follow comes from. Ultrasonic excitation of the inner ear bones is being researched currently, as people are able to deduce intelligible words modulated within ultrasonic carriers, even when otherwise deaf. People get senses of doom, nervousness, or other feelings when exposed to ultra and infrasonics, even when they can't identify the stimulus. I'd guess that spatial perception matters also exist to a significant extent outside of the 20-20k band.
Suffice it to say, I'm well convinced that you're wrong, and don't appreciate your taking potshots at me within your post. I'm not confused, babbling, or full of a steaming pile of anything.
kstrain said:
But those are all conscious perception tests, and I'm not particularly impressed with efficacy of ABX. But we agree on most points, and I appreciate the effort to stay on topic and be cordial despite disagreement.
bentoronto said:
Well, let me start with an objection to your characterizing my comments as "great 10 foot high steaming piles of amateur psychobabble confusion", you can disagree without implying that the person you're disagreeing with is confused, amateurish, and full of.. whatever. Not the way to get a good conversation going.
Frankly, I don't care what you've practiced and for how long. Expertise is not a legitimate argument. And "So pretend I didn't say that." is a ludicrous attempt at an 'out' for your rude and presumptuous preceding paragraph.
Who said anything about high enough levels of playback to shake the sternum or make wax drip from your ears?
I suggest you take the time to review audiology a little bit, the Bell Labs research was pretty weak, and that's where 20-20k guideline you seem to follow comes from. Ultrasonic excitation of the inner ear bones is being researched currently, as people are able to deduce intelligible words modulated within ultrasonic carriers, even when otherwise deaf. People get senses of doom, nervousness, or other feelings when exposed to ultra and infrasonics, even when they can't identify the stimulus. I'd guess that spatial perception matters also exist to a significant extent outside of the 20-20k band.
Suffice it to say, I'm well convinced that you're wrong, and don't appreciate your taking potshots at me within your post. I'm not confused, babbling, or full of a steaming pile of anything.
Re: Re: We are different, but ...
I'm always looking to learn, so disagreement is not very important except as a lever for improved understanding.
But regarding ABX: if I can't tell "which is which" how can I be distinguishing which is which? It is often easy to hear a difference, but then the statistics tell me I was inconsistent! I'm easily fooled.
I don't exclude that other people can hear what I can't.
Now I'm not doing so well at staying on topic.
Ken
badman said:
I'm always looking to learn, so disagreement is not very important except as a lever for improved understanding.
But regarding ABX: if I can't tell "which is which" how can I be distinguishing which is which? It is often easy to hear a difference, but then the statistics tell me I was inconsistent! I'm easily fooled.
I don't exclude that other people can hear what I can't.
Now I'm not doing so well at staying on topic.
Ken
Re: Re: Re: We are different, but ...
Well, I suppose the drifting off topic was inevitable with this topic, given that we're discussing frequencies outside the 20-20k range.
If you can't tell the difference when doing ABX, that tells you... that you can't tell the difference when doing ABX. Many audible effects are swamped by psychology under test circumstances, but it doesn't mean that they're not there, just that they're not demonstrable via that test.
I've seen people fail to reliably recognize the difference between 2 very different speakers during blind tests, but I don't think anyone would be foolish enough to say that it implies that there are no audible differences between, say, maggies and full-range driver loudspeakers.
Well, I suppose the drifting off topic was inevitable with this topic, given that we're discussing frequencies outside the 20-20k range.
If you can't tell the difference when doing ABX, that tells you... that you can't tell the difference when doing ABX. Many audible effects are swamped by psychology under test circumstances, but it doesn't mean that they're not there, just that they're not demonstrable via that test.
I've seen people fail to reliably recognize the difference between 2 very different speakers during blind tests, but I don't think anyone would be foolish enough to say that it implies that there are no audible differences between, say, maggies and full-range driver loudspeakers.
On Discovery channel there was a documentary about infra sound, which is what you would want in a SUB woofer for DVD.
They proofed that low frequency's are very important and even dangerous in some situations.
A building that was built a mile away from a tunnel that was pointing right at this building, had very bad consequences. I'm sorry to say I can't remember what it was, building crumbling or people getting sick, its one of these two, but there where many aspects in this documentary, so I can't remember them in the right order.
Another thing tested was with children, about 5 years old I think. Children don't lie about these tests, they don't even know what it is.
But they did report being a bit scared at some point, when there was infra sound.
Also a haunted house especially build for scientific testing of several aspects of 'human fear' or something, infra sound had the biggest effect.
I'll try to look up the documentary instead of keeping to guess about what I saw ...
....
Bart.
They proofed that low frequency's are very important and even dangerous in some situations.
A building that was built a mile away from a tunnel that was pointing right at this building, had very bad consequences. I'm sorry to say I can't remember what it was, building crumbling or people getting sick, its one of these two, but there where many aspects in this documentary, so I can't remember them in the right order.
Another thing tested was with children, about 5 years old I think. Children don't lie about these tests, they don't even know what it is.
But they did report being a bit scared at some point, when there was infra sound.
Also a haunted house especially build for scientific testing of several aspects of 'human fear' or something, infra sound had the biggest effect.
I'll try to look up the documentary instead of keeping to guess about what I saw ...
....
Bart.
Sorry, didn't find anything from discovery channel.
But in several video-websites there are clips about infra sound.
Maybe this would be a good place to start:
http://en.wikipedia.org/wiki/Ultrasound
If you wonder why 10hz to 25hz is important, it's because you feel it and the result is excitement, even anxiety.
That's what a LFE channel is all about for movies.
Bart.
But in several video-websites there are clips about infra sound.
Maybe this would be a good place to start:
http://en.wikipedia.org/wiki/Ultrasound
If you wonder why 10hz to 25hz is important, it's because you feel it and the result is excitement, even anxiety.
That's what a LFE channel is all about for movies.
Bart.
Badman criticizes me for criticizing him. But it is badman who begins by arrogantly propounding weird ideas at length without the personal insight to preface it with, "Although I am an amateur in these matters...." or "Although flying in the face of generally accepted opinions....." or even "I guess...."
Moving on.... some tests are reasonably definitive and some are just suggestive. (Have I mentioned that I worked at the famous Murray Hill campus of Bell Labs in the '60's?) A-B tests are pretty definitive but not perfect. Might take some time or care or focus to sense differences in a test setting.
And there are hard-to-judge situations, like the infra-sonic heebie-jeebies (I hope that term has no racial or religious or even hi-fi undertones) or the recent re-examination by real psychologists of the dismissal of that urban myth called "subliminal persuasion", or carbs and obesity. In these areas, (1) better research clarifies things as time goes on and/or (2) if the effects require very subtle test methods to explore, can't be of much practical significance in your listening room.
Returning to "subliminal" issues, in a sense that is what we are talking about in this thread. As I said previously, hear or not hear is a function of the test methods. But some methods are pretty close (or translatable) to speaking in the terms meaningful to a hi-fi person. By and large, real psychologists are skeptical about the influence of stimuli you can't report sensing or otherwise reacting to in a test. That's what "subliminal" means, right?
There are some influences that are known but which are hard to test-for, perhaps because respondents simply don't have words for the experience or otherwise can't be expressed, even if sensed in some sense I can't define....... Before anybody thinks I am getting into "golden ear" land, these are suspicious exceptions and certainly not something that egotistical loudspeaker builders should claim as their special powers of perception. Well, not without blushing.
BTW, nobody should confuse average hearing abilities (or life expectancy) with an individual's capabilities. A guy named Briggs (Wharfdale) made that point long ago.
Moving on.... some tests are reasonably definitive and some are just suggestive. (Have I mentioned that I worked at the famous Murray Hill campus of Bell Labs in the '60's?) A-B tests are pretty definitive but not perfect. Might take some time or care or focus to sense differences in a test setting.
And there are hard-to-judge situations, like the infra-sonic heebie-jeebies (I hope that term has no racial or religious or even hi-fi undertones) or the recent re-examination by real psychologists of the dismissal of that urban myth called "subliminal persuasion", or carbs and obesity. In these areas, (1) better research clarifies things as time goes on and/or (2) if the effects require very subtle test methods to explore, can't be of much practical significance in your listening room.
Returning to "subliminal" issues, in a sense that is what we are talking about in this thread. As I said previously, hear or not hear is a function of the test methods. But some methods are pretty close (or translatable) to speaking in the terms meaningful to a hi-fi person. By and large, real psychologists are skeptical about the influence of stimuli you can't report sensing or otherwise reacting to in a test. That's what "subliminal" means, right?
There are some influences that are known but which are hard to test-for, perhaps because respondents simply don't have words for the experience or otherwise can't be expressed, even if sensed in some sense I can't define....... Before anybody thinks I am getting into "golden ear" land, these are suspicious exceptions and certainly not something that egotistical loudspeaker builders should claim as their special powers of perception. Well, not without blushing.
BTW, nobody should confuse average hearing abilities (or life expectancy) with an individual's capabilities. A guy named Briggs (Wharfdale) made that point long ago.
Thought I'd add a few thoughts.
1. Motional feedback (or servo mechanisms) can make a woofer behave down to low frequencies. But this is generally applied to sealed boxes and that's not an easy way to make LF waves. Hard to imagine making the acoustic wattage with any size speaker in a room larger than a toilet that a pipe organ pedal makes effortlessly with air pressure.
2. Whatever the delight of super low tones (and I go to pipe organ concerts several times a year), it is impractical to allow LF clicks and audio garbage get far into your system. My guess is that a sharp cut-off at 25 Hz would never been a problem (granted, I have never heard - or believed till now - you could make 12 Hz music at home). "25" may sound high to persons with high achievement motivation, but it is my best guess even for the an uncompromised system. Even with the best of intentions, striving for sub-20 Hz notes will compromise other more important musical qualities.
3. Maybe there is some phrase like "well, kinda resembles in some couple of respects the sound of a live concert...." that actually has a meaning. God grant me long enough life fo be able to close my eyes and believe I am the presence of live instrument, even just a flute, when my hi-fi is playing.
4. My favourite lease-breaking LF source is an ancient Audio Fidelity recording of trains and boxcars bumping around. That will get your sternum stirring. Other fav's are koto drummers and Vangelis' Mythodea: Mission to Mars (no kidding, you have to hear the blast off and fun musically as well).
1. Motional feedback (or servo mechanisms) can make a woofer behave down to low frequencies. But this is generally applied to sealed boxes and that's not an easy way to make LF waves. Hard to imagine making the acoustic wattage with any size speaker in a room larger than a toilet that a pipe organ pedal makes effortlessly with air pressure.
2. Whatever the delight of super low tones (and I go to pipe organ concerts several times a year), it is impractical to allow LF clicks and audio garbage get far into your system. My guess is that a sharp cut-off at 25 Hz would never been a problem (granted, I have never heard - or believed till now - you could make 12 Hz music at home). "25" may sound high to persons with high achievement motivation, but it is my best guess even for the an uncompromised system. Even with the best of intentions, striving for sub-20 Hz notes will compromise other more important musical qualities.
3. Maybe there is some phrase like "well, kinda resembles in some couple of respects the sound of a live concert...." that actually has a meaning. God grant me long enough life fo be able to close my eyes and believe I am the presence of live instrument, even just a flute, when my hi-fi is playing.
4. My favourite lease-breaking LF source is an ancient Audio Fidelity recording of trains and boxcars bumping around. That will get your sternum stirring. Other fav's are koto drummers and Vangelis' Mythodea: Mission to Mars (no kidding, you have to hear the blast off and fun musically as well).
fizzard said:
You have not made a reasoning error; you're just overlooking the fundamentals. What you need to ask yourself is what gain means in this case. Gain as you are talking about it is the ratio (SPL)/(volume acceleration). If you hold volume acceleration constant as frequency goes to 0, volume displacement goes to infinity, so the whole notion falls apart at DC. What you need to look at it is the ratio of (SPL)/(volume displacement) as frequency goes to 0. This ratio is constant for a sealed room.
On the other hand, no room is truely sealed, so this doesn't really apply in rooms we put stereos in. The analysis may apply down to ~5 Hz or so though for a fairly sealed room.