I have read, but here too I think we are misunderstood. We just haven’t been able to release sound, transmission and e.g. air as a medium.
I refer to #189, where, I think, this door has already been opened;-)
I refer to #189, where, I think, this door has already been opened;-)
Very good.
Now, please read also the (shorter) following content
https://www.scienceworld.ca/resource/sound-vibration-vibration-vibration/
and if it is not enough for you then please do a search on your own by googling "propagation sound".
After that, anyway, I'll give up! 🙂 😍 😉
Now, please read also the (shorter) following content
https://www.scienceworld.ca/resource/sound-vibration-vibration-vibration/
and if it is not enough for you then please do a search on your own by googling "propagation sound".
After that, anyway, I'll give up! 🙂 😍 😉
;-)
Simpler: My concern was, and is, to mediate. One calls sound pressure and another pressureless. And I think I can prove both;-)
Simpler: My concern was, and is, to mediate. One calls sound pressure and another pressureless. And I think I can prove both;-)
Now it's you who are being imprecise. Knowledge of 'facts' for instance, is not the same as having a "conscious awareness" of having this knowledge. This awareness often has names like belief or faith, acknowledging some kind of distance separating the 'knower' from 'scientist'. For instance, checking if gravity still exists at a certain moment in time gives no guarantee that it will never change, and so, conclusions extrapolating into the future would be an act of faith.
I recall from earlier, you were keen to "stand on the shoulders of giants" when it comes to science, but if everybody does this, who checks the foundations to see if they are sound?
Surely it's just a matter of frequency; a 20 hz sine wave is a just a wave, but compared to a 20,000 hz sine wave, it's a movement.
Ten to 12 years ago I decided to make a pair of cheap speaker cabinets with no plan or real idea of what I was doing. I had a pile of (too thin) scrap wood left over from some real projects and one 4 hour time slot in a high school woodworking class. I bought four cheap 6 inch Pro Audio drivers from Parts Express and also got a pair of cheap "bullet tweeters" as an afterthought. The cabinets are about 1.6 cubic foot with a simple 2 X 3 inch hole in the front for a port. One of the speaker cabinet simulators pit this combination at an F3 of around 70 Hz with reasonable flatness. I have been pleasantly surprised by their performance and they have been used for lots of "testing" for 10+ years. They can be seen and "heard" here:
So, my question is, " If I stuff a wad of paper towels in the port, connect the cabinet to a 100+ watt amp, plug in a bass guitar, and simple slap the strings downward towards the pickup while lightly muting them to create a pseudo bass drum thud, why does the paper towel wind up on the floor a couple feet in front of the cabinet." This action causes the speaker cones to travel inward, away from the listener. Reversing the polarity deposits the paper inside the cabinet. Clearly some air is being moved in sufficient quantity to launch a paper towel.
So, my question is, " If I stuff a wad of paper towels in the port, connect the cabinet to a 100+ watt amp, plug in a bass guitar, and simple slap the strings downward towards the pickup while lightly muting them to create a pseudo bass drum thud, why does the paper towel wind up on the floor a couple feet in front of the cabinet." This action causes the speaker cones to travel inward, away from the listener. Reversing the polarity deposits the paper inside the cabinet. Clearly some air is being moved in sufficient quantity to launch a paper towel.
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Thanks everyone, but I'm giving up right now.
I'm sorry if there are people who I consider illustrious, but I can't do otherwise.
Otherwise it becomes a kind of holy-war and I frankly couldn't care less.
Does the air move?
Really?
Have someone of you done the experiment I suggested before?
No.
That hair won't move even a micron, but you insist on talking to me about the paper that sticks out the door of a bass-reflex.
When you will realize that you are talking about apples and pears, perhaps you will remember this fool who is continuing to show you an already acquired path that you deny.
I'm just disclosing a scientific fact, if you don't like it, it's not my fault.
And I don't have to prove anything to anyone, not even to those who believe that I stood on the shoulders of giants.
In fact, I tell him that I have never done it, but I have always seen it done by those who dare to say that cables have their own sound, that resistors made of different materials have their own sound, etc.
All this does not belong to me nor do I want it to belong to me.
Don't want to study?
It's your business, not mine.
However, no one has yet reported their results from the experiment I asked to do.
Why don't you try doing that and report here if the hair moved just one micron?
The bass-reflex has nothing to do with the propagation of sound, and when and if you are given scientific awareness you will understand the mistake you have always made.
I'm sorry if there are people who I consider illustrious, but I can't do otherwise.
Otherwise it becomes a kind of holy-war and I frankly couldn't care less.
Does the air move?
Really?
Have someone of you done the experiment I suggested before?
No.
That hair won't move even a micron, but you insist on talking to me about the paper that sticks out the door of a bass-reflex.
When you will realize that you are talking about apples and pears, perhaps you will remember this fool who is continuing to show you an already acquired path that you deny.
I'm just disclosing a scientific fact, if you don't like it, it's not my fault.
And I don't have to prove anything to anyone, not even to those who believe that I stood on the shoulders of giants.
In fact, I tell him that I have never done it, but I have always seen it done by those who dare to say that cables have their own sound, that resistors made of different materials have their own sound, etc.
All this does not belong to me nor do I want it to belong to me.
Don't want to study?
It's your business, not mine.
However, no one has yet reported their results from the experiment I asked to do.
Why don't you try doing that and report here if the hair moved just one micron?
The bass-reflex has nothing to do with the propagation of sound, and when and if you are given scientific awareness you will understand the mistake you have always made.
I've noticed an interesting phenomenon on some windy days. Standing outside, blowing bubbles (as one ought to do, regularly), I observed various turbulences, chaotic rotating air currents and so on, simply by observing the paths of the bubbles and interpreting what the air around them was doing.
Unlike their indoor behaviour, where they gracefully floated down to the floor, outdoors the bubbles seemed to diffuse very quickly, fairly evenly in every direction, travelling many metres up, left, right, etc. It actually gave an odd impression as if there was some giant static charge pushing them all away from each other, as that was the most consistent pattern I could discern from the chaos.
@ulogon
The air is certainly a very thin, fluid medium, and by doing simple, daily scientific observations like the above, it's doubtful if dynamic phenomenon such as 'movement' or 'vibration' can be readily be separated into exclusive categories. (Also, I've deprecated the word 'phenomena', as by definition phenomenon not a countable 'thing'. Please update your dictionaries accordingly.)
The interface near a woofer cone is known to produce real, measurable effects like the Doppler effect, and this can be confirmed experimentally. If a high frequency (carrier) can be modulated by a lower frequency, it stands to reason that some kind of displacement of the medium must be occurring. I.e., the air "spills sideways". It gets worse: for that to happen, there must also be rotation and acceleration, which could be additional sources of distortion, as the air has to contend with its own inertia. So if a sound vibration encounters a sharp corner like that of a speaker box, there is (+) acceleration from the positive peaks of sine waves, and also (+) acceleration from the negative peaks. Two positive peaks per cycle = frequency doubling.
I wouldn't throw in the towel;-)
First of all, I would differentiate:
One category: Transmission of "information" by means of a medium, i.e. particles: Movement of particles - but they are not being shot;-) Even a conceptual simplification into, for example, "cells" (Princeton article, #197) does not dispense with particles and movement but only serves to simplify the summation of different phenomena (a link to "Quantum theory": Planck did nothing other than conceptually pack a "phenomenon" into "cells" and call this "quantum"; quantity. And Einstein didn't understand this and turned this concept "cells" into objects: corpuscles, phonons, quanta, that would shot around;-)
We have an information transmission of sound in frequency form. If we only had a "DC voltage", we would have no "movement", no permanent "contrast" phenomenon.
Then we have another category: pressure and without pressure.
If the Princeton Kids had also dealt with kettledrum, for example, they would have published a more comprehensive article. But in the hi-fi field, we can simply look at the phenomenon of sound transmission using the example of a loudspeaker diaphragm and cabinet. A diaphragm functions both as a "bending wave", not exerting pressure, and as a piston, exerting pressure. The eardrum also functions in the same way: both as a bending wave and as a piston. Diaphragm size, diaphragm structure, diaphragm material, mass/rigidity ratio and other factors determine whether it is a bending wave or a piston.
And if we place a loudspeaker in a room, it also generates pressure when the diaphragma as piston moves, which pressurizes the entire room and transfers this pressure to the eardrum. But not in high frequency ranges.
Like this;-?
First of all, I would differentiate:
One category: Transmission of "information" by means of a medium, i.e. particles: Movement of particles - but they are not being shot;-) Even a conceptual simplification into, for example, "cells" (Princeton article, #197) does not dispense with particles and movement but only serves to simplify the summation of different phenomena (a link to "Quantum theory": Planck did nothing other than conceptually pack a "phenomenon" into "cells" and call this "quantum"; quantity. And Einstein didn't understand this and turned this concept "cells" into objects: corpuscles, phonons, quanta, that would shot around;-)
We have an information transmission of sound in frequency form. If we only had a "DC voltage", we would have no "movement", no permanent "contrast" phenomenon.
Then we have another category: pressure and without pressure.
If the Princeton Kids had also dealt with kettledrum, for example, they would have published a more comprehensive article. But in the hi-fi field, we can simply look at the phenomenon of sound transmission using the example of a loudspeaker diaphragm and cabinet. A diaphragm functions both as a "bending wave", not exerting pressure, and as a piston, exerting pressure. The eardrum also functions in the same way: both as a bending wave and as a piston. Diaphragm size, diaphragm structure, diaphragm material, mass/rigidity ratio and other factors determine whether it is a bending wave or a piston.
And if we place a loudspeaker in a room, it also generates pressure when the diaphragma as piston moves, which pressurizes the entire room and transfers this pressure to the eardrum. But not in high frequency ranges.
Like this;-?
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Hi abstract,
You say that I used the word "phenomenon", but I don't think so: please can you point out my related post? 🙂
However, I appreciate that you are not talking about the flow of air from a port of a bass-reflex speaker. 😉
Also I appreciated your explanation, although I couldn't follow it perhaps because it would have deserved references, examples and more (most of all a specific interest of mine, which isn't there), but anyway I take it for granted.
I'm not an expert in Electro-Acoustics, even if the functioning of the transducers fascinates me a lot.
Thanks for your informative effort, even if I think it's not exactly my point.
On the other hand, it would be useless for me to endlessly repeat a scientific notion that I did not discover by myself, don't you?
At the same time I wonder what is the usefulness of splitting hairs about the micro-variations of pressure (and if any) on the edge of a woofer in this context.
Like I said, that's not the point, and (sorry if as said) I'm not interested in it.
However, please note that speaking about that you are just talking about the Reproduction of Sound, through a technological medium (system) that it wants to mimic reality.
But if Sound Propagation is Science, Sound Reproduction is just Technology.
Technology that is based on a (limited) knowledge and which given its inherent imperfection needs to be regularly improved.
Instead, at the moment, the science about the Propagation of Sound does not seem to have yet been questioned by anyone, except here of course...
It seems in some way the same situation the ancients were in when they believed the Earth was flat: they didn't have enough knowledge and they believed what they saw and to which they presumptuously attributed a truth value.
If this is also the case with regards to the science of sound propagation?
No, it doesn't seem like out there has been questioned yet.
However, as we all know, the path of knowledge never stops.
Back to the Propagation of Sound, as far as I know it is still Science, at least until it will be replaced by a new demonstration of truth by scientists through the scientific method.
At this step, please why don't you tell me instead that if you put a hair in front of a driver operating at any wanted power then that hair moves?
Because you can't say it, because that hair hasn't moved and will never move.
Do you know why you can't say it?
Simple, because it doesn't move and it will never move.
Why doesn't it move while someone here states that sound moves the air when sound propagates?
If the air moves when sound propagates, why does moving air not move even a hair, not even a thousandth of a millimetre?
Please note that it's enough for me that you only answer this last question, since all the rest seems to have been already covered in detail.
I chose a generic driver since the driver type does not matter at all and also because otherwise someone else will come up again with the bass-reflex story.
Otherwise it would be a singularity, don't you?
In other words, if a woofer in a closed and sealed cabinet doesn't move a hair even at the highest power imaginable, why should I bother with a bass-reflex?
Or are you telling me that a bass-reflex loaded woofer behave like a singularity?
No, it can't be.
Otherwise we should also see an horizon of the events.
I think the hair example is a bit inappropriate: let's use a membrane, like that of a microphone.
The hair does not have to work because we are creating a "dipole"/"bipole" character here: the long wavelengths are bent around a hair: it is not able to be moved by "moving molecules" at this low frequency because of the surface. The situation would be different with high frequencies: wavelengths that correspond to the surface of the hair.
The hair does not have to work because we are creating a "dipole"/"bipole" character here: the long wavelengths are bent around a hair: it is not able to be moved by "moving molecules" at this low frequency because of the surface. The situation would be different with high frequencies: wavelengths that correspond to the surface of the hair.
Nonetheless I think it's interesting. Forearm hair shouldn't move from a mere breath of air. But the hairs do rattle about, and sound is also made right there. More sound is heard if a blockage is placed in front of a stream of air. Not just as reflections (otherwise, the sound of other people breathing would be a lot more prominent), but the collision itself seems to generate a lot more 'stuff'.
Flutes come to mind, as instruments that intelligently organise these unknown, random turbulences into meaningful resonances.
Flutes come to mind, as instruments that intelligently organise these unknown, random turbulences into meaningful resonances.
I can also think of air flow: current. And a river forms the same visible structure as a lightning strike/electric current. It also takes the path of least resistance, which is not necessarily the shortest path.
Aside: also the Grand Canyon is result of an electric strike, not of a river;-)
Aside: also the Grand Canyon is result of an electric strike, not of a river;-)
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From the source furnished by ulogon, "Air itself does not travel with the wave (there is no gush or puff of air that accompanies each sound); each air molecule moves away from a rest point and then, eventually, returns to it."
I merely asked a question which provoked an argumentative response. I do not wish to engage in such discussions, but I can say that the paper moved outward from the port because the pair of cones were jerked rearward by an IMPULSE, not a continuous tone. That impulse reduced the internal volume of the box, displacing some air which travelled outward through the only opening in the box. As the impulse vanished the box volume returned to normal and the air that had been pushed out of the box returned and the net air movement over the entire event was indeed zero. If there was no outside air movement, say from an AC vent, it is entirely possible that the exact same molecules that were present before the impulse occurred could wind up exactly where they started. This is more likely if a continuous sine wave is applied to the speaker and the frequency is high enough to keep the cone travel down.
So, one can argue the details all day long and there are valid arguments to support both sides. One only needs to apply a 5 Hz signal to a large woofer to see that the cone both pushes out from its normal resting place and pulls back from it, unless there is a DC offset present on the sine wave. The air in front of the speaker cone travels back and forth with the cone (vibrates). The net air movement from or toward the speaker is zero averaged over time. If the hair or thin strip of paper is sufficiently free to move and the speaker is producing a low frequency tone, it will vibrate. It will not move from its resting position.
I merely asked a question which provoked an argumentative response. I do not wish to engage in such discussions, but I can say that the paper moved outward from the port because the pair of cones were jerked rearward by an IMPULSE, not a continuous tone. That impulse reduced the internal volume of the box, displacing some air which travelled outward through the only opening in the box. As the impulse vanished the box volume returned to normal and the air that had been pushed out of the box returned and the net air movement over the entire event was indeed zero. If there was no outside air movement, say from an AC vent, it is entirely possible that the exact same molecules that were present before the impulse occurred could wind up exactly where they started. This is more likely if a continuous sine wave is applied to the speaker and the frequency is high enough to keep the cone travel down.
So, one can argue the details all day long and there are valid arguments to support both sides. One only needs to apply a 5 Hz signal to a large woofer to see that the cone both pushes out from its normal resting place and pulls back from it, unless there is a DC offset present on the sine wave. The air in front of the speaker cone travels back and forth with the cone (vibrates). The net air movement from or toward the speaker is zero averaged over time. If the hair or thin strip of paper is sufficiently free to move and the speaker is producing a low frequency tone, it will vibrate. It will not move from its resting position.
I guess we can all learn something, me included.
One:
Vibration, n, def:
1. the act of vibrating
2. the state of being vibrated
3. Physics. a. the oscillating, reciprocating, or other periodic motion of a rigid or elastic body or medium forced from a position or state of equilibrium.
b. the analogous motion of the particles of a mass of air or the like, whose state of equilibrium has been disturbed, as in transmitting sound.
4. an instance of vibratory motion or action; oscillation; quiver; or tremor.
# 5. and # 6. left off, because they generally do not apply to this thread.
Reference: Random House Dictionary of the English Language First Printing (c) 1968
YDMD . . . Your Dictionary May Differ
I especially like the words: motion; and forced from a position, that are found in the definitions.
Restoring air to its original position does not mean there was no motion, and does not mean air was not forced from its original position.
Two:
I love jet engines, they cause air flow, and they produce sound.
When liquid avaition fuel combines with oxygen, I am pretty sure the result is;
heat, light, vibration, thrust, and air flow through through the engine, and air flow out of the engine.
In this case, I am not convinced that everything returns to its original position.
If they stop doing all of those, it will probably be blamed on Boeing, or blamed on some scientist who discovered a new Physics theory.
Just my $0.02
One:
Vibration, n, def:
1. the act of vibrating
2. the state of being vibrated
3. Physics. a. the oscillating, reciprocating, or other periodic motion of a rigid or elastic body or medium forced from a position or state of equilibrium.
b. the analogous motion of the particles of a mass of air or the like, whose state of equilibrium has been disturbed, as in transmitting sound.
4. an instance of vibratory motion or action; oscillation; quiver; or tremor.
# 5. and # 6. left off, because they generally do not apply to this thread.
Reference: Random House Dictionary of the English Language First Printing (c) 1968
YDMD . . . Your Dictionary May Differ
I especially like the words: motion; and forced from a position, that are found in the definitions.
Restoring air to its original position does not mean there was no motion, and does not mean air was not forced from its original position.
Two:
I love jet engines, they cause air flow, and they produce sound.
When liquid avaition fuel combines with oxygen, I am pretty sure the result is;
heat, light, vibration, thrust, and air flow through through the engine, and air flow out of the engine.
In this case, I am not convinced that everything returns to its original position.
If they stop doing all of those, it will probably be blamed on Boeing, or blamed on some scientist who discovered a new Physics theory.
Just my $0.02
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The hair was just one example. 🙄
You can do it with whatever you want, let chopose you what: I could suggest a flame of a candle, do you like that?
It's amazing how you don't want to admit that whatever you put in front of it won't move.
Otherwise show me that it moves: make a video.
Or link us to any reference where it says that sound moves air and therefore that in front of a working speaker anything moves.
Please do it.
Wait, are you just referring to the lack of DC offset? Don't think anyone's disputing that. What you seem to be suggesting is some categorical difference between repetitive motion, vs a mysterious '"invisible" sound vibration, which somehow makes sound but fails to disturb physical objects.
I apologize if I did it or even if I just unintentionally gave you that feeling.
Even if it is not a justification, I came from a series of rather "provocative" objections (perhaps unintentionally so).
However, among other things, please know that you represent for me one of those illustrious people I spoke about before.
I really thank you, not for what you said in itself, but for the demonstration of your open-mindedness, your peculiar intelligence and your intellectual honesty which gave me great pleasure in reading just because they are qualities that I greatly appreciate in an interlocutor. 👍