Speakers, how do they work???

[sirsleepsalot]

basically, the subject...
I mean, how can a single vabrating piece create a full range of sounds simultaniously???

 

[blahblah99]

In every speaker, you have a physical magnet and a voice coil (which is just a long wire wound around itself many times). A voltage applied betwen the end of the wire causes current to flow through it, which in turns creates a magnetic field that'll oppose the physical magnet. That'll cause the cone of the speaker to vibrate according to the attraction/repulsion rapidly that happens to be the audio you hear.

 

[flood]

<< In every speaker, you have a physical magnet and a voice coil (which is just a long wire wound around itself many times). A voltage applied betwen the end of the wire causes current to flow through it, which in turns creates a magnetic field that'll oppose the physical magnet. That'll cause the cone of the speaker to vibrate according to the attraction/repulsion rapidly that happens to be the audio you hear. >>



what about electrostats and planar magnetics? :-]

In the most general form, you have an oscillating diaphragm.

 

[CTho9305]

I think the question is how one vibrating source can vibrate at many frequencies at once, rather than how a speaker actually works. The answer to that would be that you just add up each frequency and use the sum... if you have a graphing calculator, look at, say, sin(5x) + .2 sin(2x)... that would represent a loud high-pitched sound at the same time as a quieter, lower pitched sound.

 

[Evadman]

In the most basic sence, say you have 2 sounds. one at 60 hertz another at 1000. ( 60 hertz is base ) at 60 hertz, the speaker cone is moving in and out 60 times a second. Just because it is moving in and out at 60 does nto mean that on the way down it can not reverse a 1000th of an inch and hit that 1000 hertz note.

The problem is when you have a big cone ( 15' woofer ) the mass of the cone does not want to reverse, and you can warp the cone. Then you get noise induced. That is why you use a crossover, so only the lows go to the subs.

 

[hasu]

<< In the most basic sence, say you have 2 sounds. one at 60 hertz another at 1000. ( 60 hertz is base ) at 60 hertz, the speaker cone is moving in and out 60 times a second. Just because it is moving in and out at 60 does nto mean that on the way down it can not reverse a 1000th of an inch and hit that 1000 hertz note.

The problem is when you have a big cone ( 15' woofer ) the mass of the cone does not want to reverse, and you can warp the cone. Then you get noise induced. That is why you use a crossover, so only the lows go to the subs. >>



Actually the cone does not have to "reverse" its direction, a deceleration in its movement is sufficient. Sine wave (or a single frequency) is the simplest wave form. When two sine waves of different frequencies are added (superimposed), the result is a slighly deformed wave. When a speaker coil is fed with this, the cone moves exactly as the amplitude (of this resultant wave). Thus, we get a faithful reproduction of sound.

In the case of a big cone, the inertia of the cone, because of its bigger mass, restricts itself from accelerating/decelerating quicker. Thus cones with bigger mass fails to reprodice high frequency sound.

 

[spidey07]

And to tack on the answer to the original post as others have mentioned...

The driver is able to reproduce full-range sound because it is simply moving air. Sound is just compression/depression (doesn't matter what it is - air, water, steel). The driver is presented with a single waveform (complex) and compresses then retracts. This makes sound.

Take 6 tuning forks - accurately vibrating pieces of metal. Pluck one and you'll get a nice looking sine wave. Pluck two and you'll get something a little compltex. Pluck three and you get even more complex (please...let's not get started on harmonics, keys and the MATH of sound ), but still only one wave represented by the compression/depressoin of air. Do the same in water and you'll have the same effect - different medium, same effect.

 

[Heisenberg]

If you're really interested in how multiple sound waves combine to form one complex waveform, do a little reading on Fourier Series.

 

[Shalmanese]

Sound is one-dimensional. Like the others said, you simply add and subtract two waves together.

 

[RossGr]

Since your sensors, (ear drums) are a simple disk of thin skin, why would it surprise you that a single vibrating disk can create all the sound heard by your single vibrating disk? The whole secret in what is called superpostion, as others in this thread have said. This is the principle that all simutaneous sounds can be summed up to single pressure wave which contains ALL of the information of each component. This is how you hear after all. When listening to a live perfomance each instrument adds it's portion to the total sound pressure in the music hall which your ear then detects and the brain is able to sort out the component sounds. A speaker could be seen as your eardrum working in reverse. We feed into the speaker the total sound wave in electronic form it then transforms this electronic signal into physical pressure variations which the ear, which can only detect the total anyway, "hears" as an orchestra.

 

[CSoup]

Another interesting thing is that your eardrum can actually be used as a speaker also. Think human radio.

 

[johnlog]

csoup,

>>>Another interesting thing is that your eardrum can actually be used as a speaker also. Think human radio. <<<

That would could become very painful. Also a chance to fracture your eardrum making it not only painful but your ear may generate sounds only you can hear.

Your ear drum would make a very poor speaker as it could not generate enough volume/move air mass enough to be useable as a speaker.

One of my older brothers had an awesome sound system a looong time ago. Had a Scott stereo ampliflier with a 15 inch speaker, tweaters and mid range speakers. The sound was awesome and very loud. Loud enough to vibrate the nails out of your house. (g) He had an old engine type airplane sound that sounded like it came from the right, swooped down and went up on the left. It was so fantastic his neighbors would run outside to look for the low flying airplane.

Todays tinny tiny speaker systems cannot match that old sound systems ina heavy speaker box.

 

[CSoup]

<< csoup,

>>>Another interesting thing is that your eardrum can actually be used as a speaker also. Think human radio. <<<

That would could become very painful. Also a chance to fracture your eardrum making it not only painful but your ear may generate sounds only you can hear.

Your ear drum would make a very poor speaker as it could not generate enough volume/move air mass enough to be useable as a speaker.
>>



Yeah, I forgot to mention that you need to amplify the sound coming out of the ear before people can hear it. I can't find any links, but this used to be a very popular thing many years ago. They would hook the person somehow up to a radio or record player. Then they would amplify the sound coming out of the person's ear through either a cone or speaker system and the audience could hear music.

 

[SGP]

<< Todays tinny tiny speaker systems cannot match that old sound systems ina heavy speaker box. >>


Big Speakers still exist my father's system includes B&W 801 Matrix speakers with a 15' woofer and a Mark Levinson 336 power amp. Needless to say the combination can wake the hole neighborhood .