all you EVER need to know about speakers

[dave_Edwards 1]

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.It is pretty simple if you think about it

Voice coil motivation:

When a current is passed through the coil of wire, called the voice coil, it generates a magnetic field. This electromagnet interacts with the field in the magnetic gap and the voice coil moves. The direction of movement depends on the direction of current flow through the VC. Since audio is an AC waveform, current flows in one direction and then changes polarity, the VC moves either forward or backward from its point of rest. The cone is the part of the speaker that actually makes the sound by alternately creating an area of high and then low air pressure.

Magnitude of cone movement:

When an amplifier drives a speaker, it is driving the speaker terminals with AC voltage. If the volume is at its minimum position, the speaker doesn't move. If the driving voltage is low, the speaker moves a little. As the voltage increases (when you turn up the volume), the cone moves further from it's point of rest. Higher power amplifiers can drive the speaker with higher voltage and therefore produce more SPL (volume).

********Please note that speakers DO NOT produce power**********. A speaker rated at 1000 watts is not necessarily going to be more efficient than a speaker rated at 50 watts. If they are manufactured by the same company (so that they are rated by the same standards), the speaker rated to handle higher power will be able to produce more sound pressure level because it can be driven with a more powerful amplifier without fear of damage. Many times, a manufacturers cheapest woofers will be more efficient and may be a better choice for a low powered system.

Coaxials and Triaxials:

It is very difficult (read impossible) to build a single driver capable of accurately and efficiently reproducing the entire audio spectrum. It is much easier to use multiple drivers, each reproducing its own narrow band of frequencies. Coaxial speakers are 2-way speakers which employ a larger driver (for bass and midrange) and a tweeter (for reproducing upper midrange and treble). A triaxial speaker is a 3-way speaker with a woofer, a midrange and a tweeter. Both types of speakers usually include the required crossover components for the midrange and high frequency drivers.