PASpeaker-Base

Subwoofers

Bandpass subwoofers

The driver sits between chambers inside the enclosure; sound only leaves through ports. This gives high output in a limited frequency band.

How bandpass works
4th-order bandpass enclosure in cross-section Side section: a partition divides the enclosure into a sealed rear chamber on the left and a vented front chamber on the right. The driver sits in the partition. Sound only reaches the outside through the port of the front chamber. Rear chamber sealed Front chamber Port Port mouth the only way out
Schematic section through a bandpass enclosure. The drawing shows the principle, not the dimensions of a specific build plan.

Plans

Link to section “Plans”
  • 21″ Bandpass Partially verified

    18 Sound 121BP

    A bandpass subwoofer for a 21-inch driver. According to 18 Sound a “Double Reflex Band-Pass” with large port cross-sections, internal bracing and overdamped tuning.

    Dimensions (H × W × D)
    560 × 808 × – mm (incomplete)
  • 18″ Bandpass Partially verified

    Speakerplans 184 Sub

    A compact bandpass for an 18-inch driver. The designer names six suitable drivers and matching tube lengths for each variant.

    Dimensions (H × W × D)
    864 × 500 × 615 mm
  • 18″ Bandpass Partially verified

    Speakerplans C Sub

    A bandpass for an 18-inch driver with a crossover at 80 Hz. The designer gives the frequency range, sensitivity and five suitable drivers.

    Sensitivity
    103 dB
    Dimensions (H × W × D)
    1,000 × 500 × 626 mm