Why it matters
The enclosure is not a mounting bracket — it is part of the acoustic system. Pick the wrong volume or leak air and even a great driver sounds thin. This is why a bare driver on a bench has almost no bass.
How it works
When the cone moves forward it compresses the air in front and rarefies the air behind. Those two outputs are opposite in phase. At low frequencies the wavelength is long enough to bend around the cone, the front and rear meet, and they cancel. This is acoustic short-circuit.
A baffle — even a flat panel — lengthens the path between front and back so cancellation happens lower in frequency. A full enclosure goes further and traps or controls the rear wave entirely.
Two effects fall out of this:
- Baffle step. A finite baffle radiates into half-space at high frequencies but full-space at low ones, so output below a transition frequency is roughly 6 dB lower. Real designs compensate for it.
- Box loading. Trapped air acts as a spring on the cone. Its stiffness sets the low-frequency rolloff and how the driver behaves near resonance — which is exactly what the sealed-versus-ported choice is about.
Common mistakes
Simple example
Related concepts
Related concepts
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