Reddit mentions of Teach Yourself Electricity and Electronics, 5th Edition (Teach Yourself Electricity & Electronics)

Neither, actually.

Power compression, you are correct, is the effect of the resistance increasing as a voice coil heats up. The heat does not dissapate very quickly at all, and as such there are a few different ways to combat this. One method is to port the voice coil such that it pulls in air with every compression and rarefaction, as JBL sometimes does. Another is to use ferrofluid in the voice coil to cool it as much as possible. However, in the end, the best you can do is hope to manage the problem.

The effect, however, is the misleading part. It's not compression in the traditional sense. It doesn't really affect the audio as much as it affects your headroom. You simply will need more power to produce the same amount of SPL. It doesn't compress transients, it compresses everything within a certain frequency range evenly. What frequency range depends heavily on the driver, but safe to say it's going to be most of it.

This is something that amplifier companies have harmlessly mislead us on a bit in the interests of user friendliness. To go into a bit of depth, read on and I'll do my best to explain. (although this book:

http://www.amazon.com/Teach-Yourself-Electricity-Electronics-Edition/dp/0071741356

will explain it better than I can). For clarity's sake, from hear on out, I will try to use the term 'speaker' to describe an entire 2 way or more speaker, like what you'd listen to music out of, and 'driver' to describe the individual component that you would use within that speaker.

There is no such thing as a simple resistance in any AC circuit, such as a speaker an and amplifier. So, on the back of your amp, when you see it's rated for 8 ohms, and a speaker is 8 ohms, that is the simple DC resistance. But if you wanted to go a step further, you would ask yourself what the resistance is at what frequency of this coil? Resistance in an AC circuit is always a complex number, and is charted 3 dimensionally. This is why the Pythagorean Theorem matters, actually. A complex resistance would look something like this: 3 - 4i, and Pythagorean Theorem is the trig that turns that into a 3d chart of a drivers frequency response. You know, like the one that is on every manual for every speaker sold? And Microphone? This is how they get that information.

As you move up a coil's frequency range, the resistance of that coil will increase. Likewise, as you move down it's range, it's resistance increases. As the resistance increases, it requires more and more power to get the same amplitude out of that driver. At some point, it becomes such a impractical amount of power to drive that driver at that frequency or any higher or lower, it's time to cross it over and use another one. This is due to inductance and capacitance, and without going into too much detail here this is what determines a driver's frequency response. These are the properties speaker manufactures look at when designing a coil.

Of course, using 2 or more drivers then means you have to worry about phase coherency, which is of course also 3 dimensional. And you have to worry about a nice tidy crossover. Always a compromise.

Therefore, any increase in the temperature of a coil will affect the frequency response, but within a certain range. It doesn't matter what you put into it, if it's transient or not, it will be affected evenly based on frequency, not amplitude. But you don't really hear this affect. It just makes the amp work harder for the most part. This is why a drastically under powered amp will do fine for a while, but will eventually either fail or damage the coil. (one common problem with JBLs, when underpowered for example, is because they're air ported if the amp clips early, they don't get their maximum throw and fail to pull in enough air. Always use BIG amps with JBLs, twice the rated power. Or do what I do, and don't use them at all. JBL = Junk But Loud).

So power compression is exactly that, compression of the power (wattage) of the amplifier. It has much less to do with audio.

It should also be noted that microphones work exactly the same way, but the math is in reverse. What voltage can that coil produce given how much SPL at what frequency?

Teach Yourself Electricity and Electronics, 5th Edition by Stan Gibilisco

There are 3. The 2 that are connected together are probably ground. So, tip to one, ring (middle connection) to the other, then sleeve (ground) to the 2 that are connected. Can't really be sure about left/right at this point. would require some experimentation.

Also, don't blow a pair of headphones! just go down to a radio shack and get an 1/8" connector. Then, find some cheap stereo wire. You need a wire with 2 conductors (as in, jacketed wires) and an outer shield. the outer shield is ground, and the two inner wires are the left and right sides. This completes the circut.

Oh, also, go to radio shack and by a good volt/ohm meter if you're interested in this stuff. It'll help you in the future detirmine things like which leads on this tape head are what. Also, read this book:

http://www.amazon.com/Teach-Yourself-Electricity-Electronics-Edition/dp/0071741356/ref=sr_1_1?ie=UTF8&qid=1371353158&sr=8-1&keywords=Stan+Gibilisco

Stan Gibilisco's Teach yourself electricity and electronics. Fantastic book. Huge, but take it in chunks. You'll understand how this works and many other things!