Short answer:
No, the above is impossible.
Long answer:
Sound is represented as a sinusoidal wave called "wave of pressure" which expresses the compression and rarefaction of air molecules.
Sound is a form of energy (mechanical and vibratory) that is generated by an object that vibrates.
Those vibrations will be transferred contiguously to the nearest air molecules in a flow (sinusoidal wave) that defines the sound propagation mechanism.
Molecules of air vibrate, but do not move, in other words sound involves the air only in terms of the movement of energy, but not of matter.
Otherwise we will hear a "wind" together with a sound, and we don't.
Said that, the answer to the question in the title of this thread is that sound is always as "push and pull" (or "pull and push", it depends from the point of view of the observer) since each compression will always be followed by a related rarefaction.
On the other hand, a woofer, just as a more visible example, behaves exactly this way.
And it couldn't be otherwise, precisely because after having caused a compression of the air molecules, moving forward, then the driver diaphragm return back causing a rarefaction of the air molecules.
This occurs even if you change the absolute phase since the process remains the same: a compression is followed by a rarefaction and a rarefaction is followed by a compression. 😉
Thank you very much again Just for fun i have simulated a circuit with a diode placed before the load So that only the positive portion of the sine reaches the load
The resulting THD is a mess indeed Shocking
You say
It will not be wind i agree The wind is a different phenomenon It is an air displacement caused by barometric differential pressure between two points
This barometric pressures in point A and point B do not vary with frequency but stay quite steady
The resulting THD is a mess indeed Shocking
You say
No but we can feel some air displacement with big woofer and low Hz signals
It will not be wind i agree The wind is a different phenomenon It is an air displacement caused by barometric differential pressure between two points
This barometric pressures in point A and point B do not vary with frequency but stay quite steady
Absolutely not.
What you describe is absolutely impossible.
Not even the world's largest woofer could move a single molecule of air.
Sure, I called it "wind" just to be picturesque trying to make myself better understood. 😉
1. Consider a large diameter Orchestral Thunder Drum:
The struck side of the thunder drum will have an Initial Transient Rarefaction of the air.
The non-struck side of the thunder drum will have an Initial Transient Compression of the air.
The amplitude of Rarefaction is equal to the amplitude of Compression,
Depending on which side of the drum diaphragm you sit on, you will have a different initial transient impulse of the air.
Let's move from the concert hall, and into the living room (do not bring the thunder drum, it is taller than your ceiling).
Instead, let's talk about the air on one side of an open baffle speaker, and the other side of an open baffle speaker.
One initial transient is rarefaction, and the other initial transient is compression.
2. Movement of air?
Have you Ever Heard; or Never Heard, the Chuffing of air that is moving into, and moving out-of the port of a ported reflex woofer box, or ported reflex 2-way speaker?
I have heard it, and have felt it too.
The struck side of the thunder drum will have an Initial Transient Rarefaction of the air.
The non-struck side of the thunder drum will have an Initial Transient Compression of the air.
The amplitude of Rarefaction is equal to the amplitude of Compression,
Depending on which side of the drum diaphragm you sit on, you will have a different initial transient impulse of the air.
Let's move from the concert hall, and into the living room (do not bring the thunder drum, it is taller than your ceiling).
Instead, let's talk about the air on one side of an open baffle speaker, and the other side of an open baffle speaker.
One initial transient is rarefaction, and the other initial transient is compression.
2. Movement of air?
Have you Ever Heard; or Never Heard, the Chuffing of air that is moving into, and moving out-of the port of a ported reflex woofer box, or ported reflex 2-way speaker?
I have heard it, and have felt it too.
this i do not understand So what causes the feeling of internal organs moving for instance with a track of heartquake in movies reproduced by a big system ? i do not understand There is no other medium than air between the woofer cone and the human body
Ginetto, please, I know that what I say is more than correct and frankly on a forum like this I shouldn't explain things that would be the baggage of anyone who deals with Audio.
You must realize the difference between moving and vibrating, if you don't I will no longer follow you in any reasoning.
With a sense of friendship, but I will not follow you.
Air molecules vibrate, not move, because of sound.
Let's do one thing, let's change the medium of sound transfer.
Let's take water: do you think that sound is transmitted in water by moving the water?
Let's take the lid of a steel pot and hit it: do you think that the sound is transmitted inside the molecules of the metal of which the lid is made because they move?
Obviously not.
The molecules of the transmission media through which the sound propagates vibrate, certainly not move.
And the low region of the acoustic spectrum makes objects vibrate.
It makes the floor vibrate, the furniture with the glasses, the sofa where you are sitting, the walls that surround you and your own stomach where you feel something vibrate.
But do you think what makes the sofa vibrate is the moving air?
That video you showed is a joke, right?
The sheet of paper is placed in front of the door of a bass-reflex cabinet: it is obvious that air comes out from there at "high" pressure.
Frankly, I don't know how to tell you this, but I shouldn't convince you of this, because this is an established fact.
If you resist, I don't know what to do about it frankly.
But you really didn't have to show me the sheet of paper in front of the door of a bass reflex...
This has nothing to do with sound propagation.
Sorry, but if you don't know that, it's not my fault.
I'm really sorry, just because you are talking about ignoring a basic fact, but that's how things are.
To be honest I didn't think I had to "explain" this, here.
On the other hand, if I answer you like this you will then think that I am aggressive (and I am not at all) and then you will get angry and answer me badly.
But I don't want that, and yet I'm just telling how the things are.
If you never thought about it, once again it's not my fault, sorry.
If sound was push and not pull, wouldn't it be necessary to have prefect phase throughout the sound recording, storage, retrieval, amplification and speaker, and wouldn't just one single ended stage in the process be necessary - as long as all following stages go down to a very low frequency?
Can anyone tell?
Can anyone tell?
the crazy test could be to put a diode on the plus of a speaker and listen In that way the negative portion of the sound wave will never reach the load
I guess that the resulting sound would be disastrous Maybe the amp will even blow
I guess that the resulting sound would be disastrous Maybe the amp will even blow
Amp shouldn't blow if you put diode in series with the speaker, it's just increases load impedance = easy load for amplifier. If the diode is connected across the speaker terminals then it would be a short circuit and might blow up the amp if it doesn't have protection for shorts. Either case expect fuzz pedal like distortion 🙂
If you inspect sound waveform on screen it goes up and down, also when it has passed through a diode it still goes up and down although clipped some, it's still vibration back and forth. Let's imagine sound was only push or pull, it would just go one direction, and never return. What it would mean for a speaker then? the driver cones would accelerate one direction only but never stop, so you would lose the driver cone and never see it again. Stopping it needs "negative acceleration", or deceleration, which is the pull part of sound. If you throw your speaker driver to space with escape velocity it would accelerate only one direction and never decelerate, but there would be no sound either except when it accelerates, and if the acceleration was in some medium not in vacuum so that sound transmits. 😀 so, your topic title is of course quite theoretic, never though it was a real question, was it?
ps. there is funny saying I heard in army: "A soldier never retreats; instead, he turns around and advances again"
If you inspect sound waveform on screen it goes up and down, also when it has passed through a diode it still goes up and down although clipped some, it's still vibration back and forth. Let's imagine sound was only push or pull, it would just go one direction, and never return. What it would mean for a speaker then? the driver cones would accelerate one direction only but never stop, so you would lose the driver cone and never see it again. Stopping it needs "negative acceleration", or deceleration, which is the pull part of sound. If you throw your speaker driver to space with escape velocity it would accelerate only one direction and never decelerate, but there would be no sound either except when it accelerates, and if the acceleration was in some medium not in vacuum so that sound transmits. 😀 so, your topic title is of course quite theoretic, never though it was a real question, was it?
ps. there is funny saying I heard in army: "A soldier never retreats; instead, he turns around and advances again"
Last edited:
Hi ! yes this is what i got with a diode before the load Not very nice indeed
issue closed So sound is indeed both push and pull Good to know for sure
I have to understand better these sim SW because they can provide very useful information without having to destroy anything
I have been told that it is not sure that something that works at sim can work in reality
But it is much more likely that something that does not work at sim also will not work in reality This is for me a huge step ahead
Thanks a lot again for the kind and valuable injections of sanity
issue closed So sound is indeed both push and pull Good to know for sure
I have to understand better these sim SW because they can provide very useful information without having to destroy anything
I have been told that it is not sure that something that works at sim can work in reality
But it is much more likely that something that does not work at sim also will not work in reality This is for me a huge step ahead
Thanks a lot again for the kind and valuable injections of sanity
@ginetto61
If you (or other ones) don't trust me, please believe what is written in a Princeton University document.
https://assets.press.princeton.edu/chapters/s9912.pdf
And, please, pay attention how you speak. 😉
If you (or other ones) don't trust me, please believe what is written in a Princeton University document.
https://assets.press.princeton.edu/chapters/s9912.pdf
And, please, pay attention how you speak. 😉
I found a further authoritative site from which you can read the following (the bold is mine):
"When a sound is produced, it causes the air molecules to bump into their neighbouring molecules, who then bump into their neighbours, and so on. There is a progression of collisions that pass through the air as a sound wave.
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.
When we hear something, we are sensing the vibrations in the air."
https://www.scienceworld.ca/resource/sound-vibration-vibration-vibration/
Hoping that even the most skeptical (and I didn't say ignorant, in the sense that they ignored) are "convinced" of an established fact.
It's just Physics!
"When a sound is produced, it causes the air molecules to bump into their neighbouring molecules, who then bump into their neighbours, and so on. There is a progression of collisions that pass through the air as a sound wave.
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.
When we hear something, we are sensing the vibrations in the air."
https://www.scienceworld.ca/resource/sound-vibration-vibration-vibration/
Hoping that even the most skeptical (and I didn't say ignorant, in the sense that they ignored) are "convinced" of an established fact.
It's just Physics!
Last edited:
1. According to some of the posts in this thread . . .
Some things that produce extremely loud sounds do Not have any air motion.
Instead the Posts claim it is all just Vibration, molecules vibrating back and forth.
So,
How does a Jet engine produce thrust?
How does a Rocket engine produce thrust?
No Air Flow, according to those posts.
Oh, there is air flow, And there is vibration . . . Both.
Thrust is created, air flow happens, and sound is produced.
Put some smoke in a ported speaker's enclosure, play the 6 Hz canon of the Telarc 1812 overture recording, and see whether smoke comes out, if it does there is air flow.
Use 2 speakers with smoke inside, but only drive one with the 6Hz canon, the smoke comes out right away, that is called Air Flow.
The un-driven speaker will Eventually have smoke come out, that is called Diffusion.
2. I know that there is lots of theory about air. Standard temperature and pressure (STP); molecular vibration due to temperature, etc.
The molecules move individualy in many directions, this is not considered flow.
Given an infinite time, the theory goes that all of the air molecules will briefly move to a single corner of an enclosure, no air in the rest of the enclosure.
But do not hold your breath to see if that theory is true.
In like manner . . .
Electrons do not move all the way along a wire from one end to the other, instead individual electrons move partway, passing the motion to the next electron, and so on . . . we call that current: Electron Flow.
I am glad that works.
Just my opinions
Some things that produce extremely loud sounds do Not have any air motion.
Instead the Posts claim it is all just Vibration, molecules vibrating back and forth.
So,
How does a Jet engine produce thrust?
How does a Rocket engine produce thrust?
No Air Flow, according to those posts.
Oh, there is air flow, And there is vibration . . . Both.
Thrust is created, air flow happens, and sound is produced.
Put some smoke in a ported speaker's enclosure, play the 6 Hz canon of the Telarc 1812 overture recording, and see whether smoke comes out, if it does there is air flow.
Use 2 speakers with smoke inside, but only drive one with the 6Hz canon, the smoke comes out right away, that is called Air Flow.
The un-driven speaker will Eventually have smoke come out, that is called Diffusion.
2. I know that there is lots of theory about air. Standard temperature and pressure (STP); molecular vibration due to temperature, etc.
The molecules move individualy in many directions, this is not considered flow.
Given an infinite time, the theory goes that all of the air molecules will briefly move to a single corner of an enclosure, no air in the rest of the enclosure.
But do not hold your breath to see if that theory is true.
In like manner . . .
Electrons do not move all the way along a wire from one end to the other, instead individual electrons move partway, passing the motion to the next electron, and so on . . . we call that current: Electron Flow.
I am glad that works.
Just my opinions
I find it simply incredible that some people trample on scientific knowledge by claiming that their opinions and beliefs are more intelligent than scientific knowledge.
And their intellectual arrogance is so great that even scientific knowledge is questioned.
Yet we are a Forum in which I myself have seen science and physics invoked many times immediately when someone took the liberty of saying that amplifiers don't all sound the same.
Do you think that the Science of Sound Propagation was invented by me?
What do you think an educated person will think when he reads certain enormities?
Have we returned to Obscurantism?
Do you think I give a damn about your ignorance and intellectual arrogance?
Why don't you go back to your books, please, instead of insisting on writing nonsense as if your personal thoughts was above science?
The Sun rotates around the Earth because I see it move in the sky from East to West!
It seems a perfect line of reasoning, right?
Just my 2 cents... 😉
And their intellectual arrogance is so great that even scientific knowledge is questioned.
Yet we are a Forum in which I myself have seen science and physics invoked many times immediately when someone took the liberty of saying that amplifiers don't all sound the same.
Do you think that the Science of Sound Propagation was invented by me?
What do you think an educated person will think when he reads certain enormities?
Have we returned to Obscurantism?
Do you think I give a damn about your ignorance and intellectual arrogance?
Why don't you go back to your books, please, instead of insisting on writing nonsense as if your personal thoughts was above science?
The Sun rotates around the Earth because I see it move in the sky from East to West!
It seems a perfect line of reasoning, right?
Just my 2 cents... 😉
Last edited:
My favorite explanation of electricity it a hose pipe full of marbles; if you stick one in one end, almost immediately one will pop out of the other end, but it would take a long time to keep feeding Marble's in to get that first one to work all the way along the hose.
If sound was more push than pull, wouldn't the speaker have to come towards you as you listen to music?
Are we barking up the wrong tree looking for an explanation of why (sometimes) single ended amps can sound more musical?
I think so, even if I'm not an engineer, since they are 2 different form of energy.
I believe that Electro-acoustics is a different field from Electronics since a loudspeaker is a transducer, but an amplifier is just an amplifier and the 2 things I guess are not interchangeable.
A single diode is not enough, I have tried a rectifier bridge (4 diode type) between amp and speaker, it creates a sort of frequency doubling sound effect, but I wasn't satisfied enough so added after the first rectifier, via a large capacitor, another rectifier, for juvenile shitzers und gigglers, just like me.. highly satisfying experiment!! ::)
There is a similarity of working Push Pull Amps that employ output transformers; and working Single Ended Amps that employ output transformers:
If you put a musical signal from the RCA output of a CD player Either into a push pull amp, Or into a single ended amp (and if that music signal has both a positive voltage (+), and a negative voltage (-), then . . .
The music signal outputs of Both the push pull amp, And the single ended amp, will Each have a positive voltage (+), and a negative voltage (-).
And if you apply that push pull amp output, and that single ended amp output, each to a full range speaker driver . . .
The driver cones will move: both in, and out, from the normal at-rest center-position of the driver cones.
Do you agree?
Do you disagree?
PS: A Dynamic Microphone that is in the presence of a musical group playing, will have both positive voltages (+), and negative voltages (-) . . .
According to the instantaneous sums of all the music's compressions and the rarefactions of the air.
It works that way with just a flute, a Jazz trio, or a 60 piece orchestra.
Some of those were my experiences with an oscilloscope, microphone, and a musician playing.
You could see the classical French Horn dominant 2nd harmonic wiggle on the down side of the sine wave, and then He adjusted his lips and embouchure, and the most beautiful distortionless pure looking sine wave appeared. He also could get his lip into the mouthpiece and play low pitch pedal tones that most professionals could not play. Went to Cornel U. after high school.
If you put a musical signal from the RCA output of a CD player Either into a push pull amp, Or into a single ended amp (and if that music signal has both a positive voltage (+), and a negative voltage (-), then . . .
The music signal outputs of Both the push pull amp, And the single ended amp, will Each have a positive voltage (+), and a negative voltage (-).
And if you apply that push pull amp output, and that single ended amp output, each to a full range speaker driver . . .
The driver cones will move: both in, and out, from the normal at-rest center-position of the driver cones.
Do you agree?
Do you disagree?
PS: A Dynamic Microphone that is in the presence of a musical group playing, will have both positive voltages (+), and negative voltages (-) . . .
According to the instantaneous sums of all the music's compressions and the rarefactions of the air.
It works that way with just a flute, a Jazz trio, or a 60 piece orchestra.
Some of those were my experiences with an oscilloscope, microphone, and a musician playing.
You could see the classical French Horn dominant 2nd harmonic wiggle on the down side of the sine wave, and then He adjusted his lips and embouchure, and the most beautiful distortionless pure looking sine wave appeared. He also could get his lip into the mouthpiece and play low pitch pedal tones that most professionals could not play. Went to Cornel U. after high school.
Last edited: