Speakers
Speakers:
A speaker converts electrical energy to mechanical/acoustical energy. It uses a coil of wire, which acts as an electromagnet, set inside of a magnetic gap of a permanent magnet. The following demo shows the main components of a woofer. Holding your cursor over the individual buttons will highlight the respective component.
Speakers-Thiele Small
THIELE/SMALL PARAMETERS :
SD:
Effective piston area of the cone. It will vary slightly from one 10 inch (or any other size) to another but does not vary enough to make a difference in the performance of the driver. L
Xmax:
By definition it is the peak linear travel of a driver. If you measure the distance that the voice coil can travel in the gap (in one direction) while the number of turns in the gap doesn't change, you have the Xmax. If you go past this point, the actual windings in the voice coil start to leave the gap. The diagram below shows the voice coil at its maximum travel at point of
Resistance vs Impedance
Until this time, we only discussed resistance. I said that resistance is the opposition to the flow of current. While this is true, it would be more precise to say that resistance is the opposition to the flow of direct current. Impedance is the opposition to the flow of alternating current. AC causes some devices to act differently than they do with DC. This is true with speakers. If you use a voltmeter to measure the resistance of a speaker's voice coil, you may read something like 3.2 ohms (resistance) even if the speaker has a rated impedance of 4 ohms. The impedance of a speaker is not a constant. It's actual impedance changes with frequency and can vary greatly. Manufacturers give you a nominal impedance,
