Bassilisk.audio

Passive radiator

A port replaced by a tuned, undriven cone.

1 min read
Learn Back
Ask in forum Suggest edit

Why it matters

Small bass boxes often need a port that is too long or too narrow.

A passive radiator can solve that packaging problem. It can tune the box lower without port chuffing, but it adds cost, moving mass, suspension limits, and excursion limits of its own.

How it works

The active driver pressurizes the enclosure. The passive radiator moves in response to that pressure. Around tuning, the radiator does much of the acoustic work and the active driver’s cone motion drops.

Below tuning, both the driver and radiator can lose control quickly. The passive radiator must have enough excursion for the target output.

Common mistakes

Simple example

Sealed vs ported A sealed box traps the rear wave in an airtight cabinet. A ported box uses a tuned vent to add bass output around tuning. Why a box matters A driver radiates from both sides out of phase. Without an enclosure the rear wave cancels the front, gutting the bass. The box stops that and controls low-frequency behavior. Port noise Port noise happens when air speed through the vent gets high enough to chuff, whistle, or compress output. Speaker parameters Speaker parameters are measured driver values. They describe resonance, electrical load, moving mass, compliance, motor strength, sensitivity, excursion, and safe power.

Discussion

Ask a question Start a discussion

No discussion yet

Ask a question or share a field note tied to this topic — it shows up here.