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Start here: The Loudspeakers 101 guide

A loudspeaker converts an electrical signal into pressure variations in the air. That simple definition hides a chain of electrical, mechanical, and acoustic processes.

The easiest way to understand speakers is to divide the system into five parts.

1. The drive unit

The drive unit is the component most people casually call the speaker. In a conventional moving-coil driver, electrical current passes through a voice coil located in a magnetic field. The resulting force moves a diaphragm, which moves the surrounding air.

2. The enclosure or baffle

The front and rear surfaces of a diaphragm produce sound with opposite polarity. Without a suitable baffle or enclosure, they can partially cancel one another, especially at low frequencies.

The enclosure also changes the mechanical load on the driver. A sealed box adds air stiffness. A bass-reflex system adds a tuned port. An open baffle deliberately allows front and rear radiation to interact.

3. The crossover

A woofer cannot normally reproduce the entire audible range cleanly, and a tweeter cannot safely produce deep bass. A crossover directs suitable frequency ranges to each drive unit.

The final result depends on the drivers’ acoustic responses—not only on the electrical filter.

4. The amplifier

The amplifier supplies voltage and current. The loudspeaker’s impedance determines how demanding the electrical load is at each frequency.

An amplifier must be able to drive the speaker’s minimum impedance without overheating, clipping, or entering protection mode.

5. The room

Walls, floors, ceilings, and furniture reflect sound. At low frequencies, standing waves produce large peaks and dips. At higher frequencies, the speaker’s directivity determines how much sound reaches those surfaces.

  1. How a loudspeaker works
  2. Loudspeaker anatomy
  3. Speaker specifications
  4. Enclosures
  5. Crossovers
  6. Amplifiers and impedance
  7. Measurement
  8. Placement and room interaction