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ramteid

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Posts posted by ramteid

  8. Posted

    I never meant that a sub did not move air. I tried explaining exactly what i meant but you continue to nitpick. I said exactly what i meant, as i a subwoofer does not create wind, as in the air molecules near the sub to not get forced to the front of the vehicle by sound waves. I already stated that my ability to convey what i was meaning was lacking, but you continue to nitpick. There is a difference between wind and sound, are both types of movement? Yes. Are they exactly the same? No.

    If you cant clearly clarify or convey what you mean then maybe your own definition or understanding is not fully correct.

    I believe that i made it clear what i meant. I just didnt put enough detail in it or give definitions to help convey it. There have been 2 individuals who have been able to understand what i am saying and another who continues to nitpick.

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  9. Posted

    I never meant that a sub did not move air. I tried explaining exactly what i meant but you continue to nitpick. I said exactly what i meant, as i a subwoofer does not create wind, as in the air molecules near the sub to not get forced to the front of the vehicle by sound waves. I already stated that my ability to convey what i was meaning was lacking, but you continue to nitpick. There is a difference between wind and sound, are both types of movement? Yes. Are they exactly the same? No.

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  10. Posted

     

    i know that they propagate similar to water waves, i never said they didnt.

    Yes you did, said they don't move...and do again, right below here. Which is it?

     

    a leaf blower is a creation of wind while a subwoofer is just transfering energy through the air. smelling the voice coil has more to do with, well, smell and its ability to travel through air.

    How does this leaf blower create wind? And what is wind? To make a more clear analogy, does an air pump move air? I'd hope you say yes to this, now think about the diaphragm in an air pump. How is that different than a subwoofer? Do you claim there is a difference between water and air? If you move your hand in the water doesn't the water move? The same can be said for air. If you grab an Asian hand fan and move it through the air, the air moves doesn't it? How is this different than a subwoofer such that the sub doesn't move air?

    I am also curious how you think the smell moves? Smell is air is it not? By definition then if it travels isn't the air also traveling?

     

    and again, you continue to nitpick. does a leaf blower not pull in air and push it out on another end? that would be wind. the smell inside of the enclosure will reach the front of the vehicle without the sub ever being on, from my understanding, the air will move around and circulate any way, sound waves are not the reasoning. like i have stated over and over, i mean that sound waves to dont force the air to move, as in creation of wind, it vibrates the air back and forth, most people seem to catch on to that when i explain it to them. the only thing that the sub will do, when it comes to air moving around, is introduce heat into the environment, causing the air molecules to move faster.

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  12. Posted

    Like M5 stated a few pages back. Sound waves propagate just like water waves. And just like you are saying. When a tsunami hits Japan from an earthquake in the middle of the pacific does the water from the epicenter reach Japan? No, the energy is transferred from one molecule to another. However if close enough to the epicenter there is enough energy to displace the original. water to some degree

    Just like a large system in a vehicle. You can hear and feel the sound 100 feet away but the air in the box is no reaching you. It move and arbitrary 5 feet due to the amount of kinetic energy at the epicenter and as energy is disappated over a larger and larger area it turns into a domino effect pushing the next molecule and so on.

     

    i know that they propagate similar to water waves, i never said they didnt.

     

    Ok, I'll have a go at this. Do I have a degree? No, so take this for what it is. Just my basic understanding of "motion" and reading as an outside party on this debate.

    Ramteid says a subwoofer(AC) does not move air in the same fashion that a leaf blower(DC) moves air. Both do move air molecules, just not in quite the same fashion.

    Put two one way check valves on a sealed subwoofer enclosure, one as an inlet, the other as an outlet. Does the subwoofer move air when it is playing?

    When you overheat your subwoofer and the coil starts to stink, how does the smell get from the location of the subwoofer in the rear of your vehicle to the location of your nose in the front of the vehicle?

    Put a large plastic bag on the end of a leaf blower. Run it for one second. Reverse polarity or whatever is needed to operate the motor in reverse. Run it for one second. What happened?

    Movement is movement, but I'm not seeing that as the problem here. It seems that the argument is that AC motion and DC motion are different, while both are still a form of movement. While one + - cycle of a subwoofer cone won't send one particular air molecule from the sub to the front seat at a single shot. It is possible for the molecule to eventually get there as it moves around with its buddies.

    This probably helped no one. But in the slim chance that it would, there was my .02

    a leaf blower is a creation of wind while a subwoofer is just transfering energy through the air. smelling the voice coil has more to do with, well, smell and its ability to travel through air.

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  13. Posted

    I absolutely have no idea why you are confused. Nor do I understand at all what you are trying to say. Stating that a speaker doesn't move air is completely confusing to me. I'd like to understand so I can clarify for you. Subwoofers absolutely move air. ANY device that is moved in any medium will also cause that medium to move. Newton's 3rd law makes that very clear. For some reason I see you stating his law falls down, but don't see why you think so.

    Everything i have posted link wise conveys what i am trying to say, which is what physics states. The air molecules move but the air molecules do not travel, as in, from the sub to the persons ear, the energy that travels through the air does. So, the energy travels until it vibrates air molecules that are near and in our ears, causing the ear drum to vibrate with the air molecules, which goes into the cochlea, which has tiny hair like cells that convert the vibrations into electrical impulses, then they are sent to the brain. That is the process, that is how it works, if you have an issue with understanding it, then im not sure what to tell you.

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  15. Posted

    What type of energy is that?

    Kinetic?

    Now we are getting somewhere.

    Ek = 1/2 mv2

    Notice the v in the equation, it's velocity. Pretty sure if you look up the definition of velocity that you will find it is motion which means it is moving.

    You are still stuck on what i am meaning by movement. Yes, subwoofer moves air, as in it vibrates the air molecules; they move back and forth, they oscillate from a given point, but they do not force the air to travel from one point to another.

    Im pretty sure an anemometer wont measure the winds from a speaker system since they do not create wind. This video shows what i am stating when it comes to waves from a speaker, albeit, not for very long, but it shows it.

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  17. Posted

    One other tidbit

    i did not mean it doesnt move air at all, i meant that it does not force air to travel from the subwoofer in the back of the vehicle to the front of the vehicle; it is a tranfer of energy.

    You stated it didn't move air before. Obviously I think this is more of a communication concern than right/wrong. As for the clarification you cited, if it doesn't move air then "hair tricks" won't work. If you see this differently though I would like to understand why.

    Generically speaking there are two ways to "move" things. The first is with a forcing function, F=ma (2nd law btw) and the other is to excite a resonant response. I've measured the resonance of every part of the human body and generically speaking hair resonance doesn't fall into the realm of what a subwoofer plays. And yes, even with resonance you need some forcing function, it is just it takes an awful lot less energy to do the work you are trying to accomplish (or more likely avoid).

    As for NCC's response, sure boundary conditions alter how things are perceived and actually what happens, but they don't change the laws of Physics or how waves operate.

    Hairtricks would be the same as someone levitating an object, such as a cup or a piece of paper,in their window. The sound wave is energy, the energy can pass from one medium to another. So, some of the energy that is in the air is tranfered to the air, causing it to vibrate like the air molecules. Same with an echo, when the echo reaches a barrier, part of the energy is transfered into the barrier and some is reflected back to the person.

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  18. Posted

    You changed one other thing now as well. In your first post you literally state, "With a subwoofer however, it does not move air at all". Obviously this isn't the case.

    At the same time, your premise is also wrong. Waves do move what they interact with. Vibrating is motion but they also propagate.

    I do think we aren't following what you are trying to convey though. I would like to understand what it is though.

    i tried to convey what i was meaning by it does not move air. i did not mean it doesnt move air at all, i meant that it does not force air to travel from the subwoofer in the back of the vehicle to the front of the vehicle; it is a tranfer of energy. so, the air molecules vibrate, they are pushed until they hit another molecule, after they hit that molecule, they are pushed with equal force in the opposite direction and the next molecule continues the process. is that not the third law of motion?

     

    i believe the confusion lies not only in scale but in controlled mediums for examples. such as the slinky and rope bridge thing they used in teh video to describe how a wave moves are both ridged and tethered mediums for the wave to pass through. in much the same way that you see a concrete building ripple in an earth quake you see the examples in the video move up and down to transfer the waves energy from one side to another but you do not see the medium moving out of its horizontal spacial location.

    the second aspect is what you feel when you hear a speaker. take a massive speaker with large excursion in a ported box. i do not think the argument would be made that the air coming from the port is not moving. you could say that its not if you attempt to factor in combined movement through out a full reference wave length but that would again be misinterpreting the effects. when the sub pushes or pulls and you are close to the speaker you can feel the air blow in or out from the port and from teh cone. when you get farther away you no longer feel the air motion so you assume the air is no longer moving. this goes right back to the issue of scale. however the air movement is what enables you to hear the sound wave so far away and just like stated above the air is not bound to anything. the weak and strong forces that govern the movement of atoms play a part but its not like the air itself is in any way tethered like the example mediums used in teh start of hte video.

    the third aspect i think may be a confusion is the very definition of "movement". if we have air being blown by a leaf blower or air carrying a sound wave in both situations the air is moving but with a different amount of force and in a slightly different interaction. still both of these constitute as "air movement" however.

    i think your confusion lies in the assumption that sound waves and wind are some how equivalent. if the subwoofer moved air, as in it pushed it and the air near the sub was moved to where the driver was, then it would be similar to the wind. so, if that was true, people would not be able to levitate objects, such as cups or paper, at their windows.

    here is a linke, http://www.mediacollege.com/audio/01/sound-waves.html and in there you will see there it says, "Note that air molecules do not actually travel from the loudspeaker to the ear (that would be wind). Each individual molecule only moves a small distance as it vibrates, but it causes the adjacent molecules to vibrate in a rippling effect all the way to the ear."

     

    if i am incorrect, that would mean that physics is completely incorrect and you should invest some time in rewriting physics books and be the next newton. now, i am not denying that my terminology and description of what i mean is lacking. also, i am not saying that the air within the vehicle will not be moving, or circulating, while the sub is transfering energy, just that the air is not circulating due to the sub.

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  19. Posted

    I can not tell you who is right or wrong because I have not taken enough courses or have experience in this subject, but I will take M5's word for it.

    Can you really argue with someone who has a degree and many years of work experience in this particular subject?

    Like i said, my method of conveying what im trying to say is lacking. Ill be more specific. Sound waves do not move air, as in they do not force air to travel from where the speaker is to where the user is, the energy from the speaker travels through the medium, in this case air. They do move air molecules, as in they vibrate, or oscillate, the molecules, which is compression and rarefaction, so the air molecules move back and forth from where they are. Now, the greater the amplitude, or energy, the more molecules that are compressed.

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  22. Posted

    I think what he trying to convey is they excite the air rather than move it from one place to another like a pump. The pump could/would create vacuum. It is still movement, I just think that's how he's envisioning it.

    Thank you, that is exactly what i was trying to say.

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  23. Posted

    So taking another look at this write up, I've confirmed the results as well with other sources. The Vf value is the PORTED section, while the Vr is the SEALED section. So can someone please please provide an explanation, why EVERY BP Enclosure I see, the PORTED section is LARGER than the SEALED section? Generally speaking, the owner will describe their BP as an 1:1 / 2:1 / 3:1 ratio . And when they describe that's their enclosure, it, again, is referring to 1 ported to 1 sealed, 2 ported to 1 sealed, or 3 ported to 1 sealed. But this is TOTAL opposite of not only the cookbook, but other sources, including this write up by Quentin.

    I'm looking for a real answer to this question, not just, "their doing it wrong", or "because they seen it on youtube". Like, there has to be some truth to why the masses are doing it this way. This way being the ported section is larger than the sealed section.

    That's the first thing I have in question. Second thing.

    Continuing with this write up/example that Quentin has provided:

    lets set it to 25hz. I think that'll be low enough and we get:

    Vf = 1.387 (see we used the same s factor and it remained the same)

    Vr = 1.814

    Qbp .1.08

    fb = 43.65 hz

    passband = 25-76.21 hz (high f3 is a bit high but I'll use the filter on the amp to bring this down a bit.

    gain = 3.21

    If the Vf value is 1.387, and the Vr value is 1.814. Does the Vf value INCLUDE port area, or is that another factor not listed? Do we even need to include port area in this calculation? If so, then how do we calculate the port area that is needed, and add it in?

    Well, the reasons for them using the ported side varies from my experiences. A larger ported side will be more efficient, thus more spl at the cost of frequency response, and some people want that type of response. Others i have talked with are just guessing and dont know what changing any of it does, so they are just doing with what they have seen.

    Btw, this thread should be stickied, because it is very informative and it would make it easier to find later down the road, especially since i sometimes post it for others to read.

    Hmmm, interesting. Because even at 2x and 3x events. World champions are using like, big 3 or even 6 to one ratio. But again, that's ported to sealed. Not as suggested by the cook book.

    I dont remember what all the cookbook says, but i know if i was making one for myself for music it would be a small ratio or even larger sealed to ported, depending on the subs, but if i was going for spl i would use a large ported to sealed ratio. Also, playibg around with winisd i am rarely able to get a response that has similar output to a bass reflex enclosure without going with a larger ratio of ported to sealed, but then it becomes too peaky for me.

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  24. Posted

    So taking another look at this write up, I've confirmed the results as well with other sources. The Vf value is the PORTED section, while the Vr is the SEALED section. So can someone please please provide an explanation, why EVERY BP Enclosure I see, the PORTED section is LARGER than the SEALED section? Generally speaking, the owner will describe their BP as an 1:1 / 2:1 / 3:1 ratio . And when they describe that's their enclosure, it, again, is referring to 1 ported to 1 sealed, 2 ported to 1 sealed, or 3 ported to 1 sealed. But this is TOTAL opposite of not only the cookbook, but other sources, including this write up by Quentin.

    I'm looking for a real answer to this question, not just, "their doing it wrong", or "because they seen it on youtube". Like, there has to be some truth to why the masses are doing it this way. This way being the ported section is larger than the sealed section.

    That's the first thing I have in question. Second thing.

    Continuing with this write up/example that Quentin has provided:

    lets set it to 25hz. I think that'll be low enough and we get:

    Vf = 1.387 (see we used the same s factor and it remained the same)

    Vr = 1.814

    Qbp .1.08

    fb = 43.65 hz

    passband = 25-76.21 hz (high f3 is a bit high but I'll use the filter on the amp to bring this down a bit.

    gain = 3.21

    If the Vf value is 1.387, and the Vr value is 1.814. Does the Vf value INCLUDE port area, or is that another factor not listed? Do we even need to include port area in this calculation? If so, then how do we calculate the port area that is needed, and add it in?

    Well, the reasons for them using the ported side varies from my experiences. A larger ported side will be more efficient, thus more spl at the cost of frequency response, and some people want that type of response. Others i have talked with are just guessing and dont know what changing any of it does, so they are just doing with what they have seen.

    Btw, this thread should be stickied, because it is very informative and it would make it easier to find later down the road, especially since i sometimes post it for others to read.

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  25. Posted

    That explains some, but at the same time i still dont think it moves air, as in pushing the air, if it did, would it not create a vacuum? My understanding is that it vibrates the air, not necessarily move it.

    If put a piece of tape on the end of a bound up slinky and then let it go does the tape move?

    Can you move in a sine wave without any velocity?

    Can you do a hair trick if the air isn't moving?

    Does water move when you push your hand through it?

    Do you need me to go on?

    The examples you have given arent that great. A better example would be putting a piece of tape on a part of a slinky and move one hand side to side. The energy transfers throug the slinky, making the slinky move to a certain extent, but once the energy dissipates the slinky will be in the same exact resting place as it was before the energy transfer, thus the tape would also be in the same place. Or, you could see it as a rope that is held on both ends, when someone moves one side up and down quickly you will see the rope form a wave of energy that is transfered from one end to the other, the rope itself will go back to the same resting place it was previously. That is how sound waves are transfered through mediums such as air.
    Maybe you should stop trying to read what isn't there.

    If you constrain the slinky in the stretch/compress direction it is akin to holding your speaker cone completely still.

    Perhaps when you move your hand through the water in a lake/bathtub/pool the water doesn't move in your mind, but I bet it is moving.

    And btw, sound is only transferred when it moves energy. Same with any wave. They are all kinetic.

    Curious in your example, did your hand 'move' the slinky?

    Han transfer energy to it, just as with the rope example. But if a sub moved air would it not create a vacuum? If so then how would the sound wave continue to travel past the vacuum? Apparently phsyics is completely incorrect about how sound travels.
    http://www.physicsclassroom.com/class/sound/u11l1c.cfm
    I already know that. All im trying to say is that air is the medium with which the sound travels and basically, the medium does not move. All the medium does is transfer the energy.
    If you knew that you wouldn't have posted that speakers don't move air.

    Do waves in the ocean not move water? If the waves move water how are they different than acoustic waves?

    That is what i meant by they do not move air, they vibrate it. Moving air would be more like wind, vibrations are more back and forth movements. Maybe i should have tried to convey that in another manor.
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