Totally off topic, but I'm sitting here, haveing a few beers and listening to music through a pair of early-70's vintage KLH model 17's, and it got me thinking...
How the heck does a speaker even work? I'm not talking about how electricity powers the magnet to move the cone - I'm talking about not only how it can reproduce a specific sound, but how it can do multiples at the same time.
Example - a piano at middle C, a guitar at middle C and a vocalist at middle C are all creating a tone of the same frequency, yet they have a different sound. Not only can a speaker recreate each, it can do them all simultaneously, at the same frequency but being able to hear each individual instrument. How can it do that?
At the same time... We can take middle C again, it's running at a specific frequency. In my mind, that means the speaker cone would need to be moving at the same frequency. Now lay another note on top of that an octave high - this note is at double the frequency. My mind says the speaker would need to move at twice the speed, and yet, it's able to produce both notes at the same time.
I just can't wrap my head around how this is possible...
Basically a speaker does the exact opposite of what your eardrum does. Your eardrum vibrates on multiple levels at one time, so you can hear overlaid sounds. The speaker...does the same thing, but instead of absorbing the sound waves, it makes them.
And of course, the sound waves get put "in" to the system by another "eardrum" - the diaphragm of a microphone. From the mic, to the speaker...it's all electronics and magnetics.
The wave forms all add up (and subtract up), so what you hear at any given moment is single waveform... though certainly an insanely complicated one.
The complication doesn't bother the speaker, it just responds to the electromotive force.
The real voodoo happens in your brain, a very sophisticated neural net, which is capable of taking a single (insanely complicated) waveform and using pattern recognition to deduce the specific elements that likely contributed to that final single waveform. That's the tricky bit!
Most speakers are of the electromagnetic design; the ones that fascinate me are the electrostatic ones. The entire surface of the speaker emits sound- however, it cannot do low/bass frequencies. Gotta get a subwoofer for that.
The speaker is making multiple sounds. A piano never makes just one note. lots of sympathetic vibes going on.
Want really weird? Recordings have been made using 2 mics in a head form. So if you record mono, or regular stereo at a noisy party, you get noise. Record with mics set human skull distance apart, set in ear shaped fittings, and you can pick out the separate conversations because of the nature of the outer & inner ear at direction sensing.
( of course the very coolest sound systems are classified and used in U.S. Navy submarines )
yea maybe...but he is so correct in this instance and freakin hilarious. A) The only thing that's freakin hilarious is how absurdly thin the argument against this stuff is.
B) What on earth was it about this thread that led you to believe that was a relevant video to post?
Back on topic -
Would I be incorrect in assuming that when a speaker replays a sound, it doesn't have to make full strokes of the cone at a time? Meaning - it can push out all the way, retract some, then push out a little more, then retract all the way? That would clear things up.
That is correct, the cone does not move full-stroke unless it has a kick drum to reproduce and you want it LOUD. Most times, it just vibrates somewhere in the middle zone of its available stroke.
To visualize...turn a speaker so the cone faces up at the ceiling. Put a dime in the cone, just sitting there. Turn it on. Normal sound, the dime will just sorta walk around a little bit, bounce, vibrate...now throw in some Beastie Boys and crank it up. That dime will most likely catch air, as the cone goes full-stroke (amplitude).
Close your eyes and listen to a sound. Picture where it is in space. You will be really close.
How does the brain decide where it is left to right? Well, the source of the sound is hitting the closer ear before it hits the further ear. So the brain uses the time difference to decide where right to left the image is. Cool, but straightforward I suppose.
Now the impressive bit... how does the brain decide if that sound is 45 degrees to your right in front of you, or behind you (remember, your eyes are closed). Both will be exactly the same to the ear in terms of time delay.
It does it by the way the tone of the sound changes as it wraps around your head and ear. When it comes around the front, it is distorted in one way. When it comes around the back, it is distorted in a different way. Picture the difference listening to a piano in a tile bathroom, or listening to a piano in a carpeted room with drapes.
Your brain recognizes the change wrapping around and uses that to decide if the sound is in front or in back.
If you were to do a SUPER slo mo on a speaker cone you would see there are lots of dynamics going on. As the cone makes larger excursions for the lower notes, the cone is being modulated by the voice coil at higher frequencies as the cone moves in and out. That's how it reproduces multiple frequencies at the same time. As these tones mix, they produce over tones that make up the timbre of a instrument. Think of the example of the piano, guitar and vocalist mentioned above. This is a very simplified explanation but is the basics..
Sort of.... They had a Mylar membrane with fine wires bonded to the surface. Underneath was a series of permanent magnets that interacted with the magnetic fields around the wires.
Electrostatic (like the Infinity Servostats) used a charge on the membrane.
The old Magnaplanes were made in MN somewhere, White Bear Lake or Forest Lake if memory serves.
These are the ones I'm familiar with. I bought my XR-1000 from Eddie Hawkins when he was at Keif's Pro Audio and I used to hang out and listen to these . . fairly off the charts.
Court, I listened to a set of those a while back and almost wet myself... I passed on them. I figured if I was paying $23,000 for a set of speakers, they had damn well go to the fridge and get me a beer when I wanted one. They just sit there and sound and look good. No beer....