Passive Radiators


Model No. SLAPS-15v2
Shop Here For SLAPS-15v2

Designed to perfectly complement all good quality long-throw woofers on the market, Earthquake SLAPS-15v2 passive radiators add up to +6dB of bass compared to regular sealed and ported enclosures and can be integrated into virtually any sub/cabinet combination. SLAPS is a patented type of passive device that significantly increases subwoofer efficiency and ability for ultra-low frequency reproduction. SLAPS is short for Symmetrically Loaded Audio Passive System. As the name indicates, SLAPS is built symmetrically, which distinguishes it from traditional passive devices. It integrates identical components in its suspension design that creates identical stroke regardless of forward or backward motion. The high efficiency and performance are a result of the pneumatic coupling between SLAPS and an active driver. SLAPS overcomes the limitations known from the conventional sealed and ported enclosures that tend to limit excursion. The unique design allows the active driver compression-free excursion resulting in deep, dynamic, and powerful bass response.

SLAPS design differs from other passive devices by having double edge suspension and no center spider. SLAPS is designed from the ground up to be operated and controlled pneumatically. Traditional passive devices are often just a normal active driver where the primary motor system (voice coil and magnet) has been removed. Conventional devices are designed to be powered electrically in which the force emanates from the driver's conical center. A passive device is operated pneumatically by air pressure from the active driver. For pneumatic operation, a traditional unit does not perform identically in positive and negative pressure environments. (imploding edge suspension and positive over ring).

SLAPS have a dual structure of identical opposites, ie. that there is an introvert and an extrovert edge suspension and no spider. This gives identical properties in both the negative and positive pressure domain. SLAPS thus behave pistonically and accurately, they do not have the “hesitation” traditional passive devices seem to have when you observe them in operation.

SLAPS enables the transfer of high amplifier power into low frequency output. Since the device does not have to fight against increasing pneumatic pressure in a closed cabinet or over-excurt close to a port tuning frequency. SLAPS has no annoying port noise and enables deep bass from a compact volume. SLAPS promotes the dynamics of a small system in which a closed enclosure design has difficulties. In a closed cabinet design, the pneumatic loading of the woofer increases as a function of its travel, this causes compression. SLAPS technology possesses none of these limitations.


  • Installs just like a subwoofer
  • Slim-mount design is only 3-inches deep
  • No increase over existing sealed subwoofer enclosure sizes
  • Increases output without added amplifier power or enclosure volume
  • Suitable for high output needs where space is limited
  • Compatible replacement for damaged Sunfire passive radiator
  • Adds up to +6dB of bass compared to regular sealed and ported enclosures
  • No annoying port noise


  • This version does not feature an adjustable mass for tuning.
  • It is designed for a 2 cubic feet (56 Liter box) and at a tuning frequency of 19 to 20Hz.
  • Keep at least 2 inches (5cm) of free air behind the SLAPS-15v2 for it to be able to move freely.
  • The SLAPS-15v2 passive radiator is also used in our home audio subwoofers, such as the MiniMe DSP P15.


  • Cutout Diameter: 15.27” (388mm)
  • Overall Diameter: 16.61” (422mm)
  • Mounting Depth: 3.25″ (85.5mm)
  • Weight: 6.08 lbs (2.73 kgs)


  • Mmd: 983 g
  • Fs: 13Hz
  • Vas: 5.228 cu. ft.
  • Qms: N/A
  • Cms: 0.1820 N/mm
  • Mms: 995 g
  • Qt: 0.38
  • Sd: 760 cm3
  • Xmax: 4″


  • Download
  • Cut Sheet

    Related Items

    Follow Earthquake

    on Social Media