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Four black passive radiators, 70mm outer, 55mm inner, 4.5mm high

Unique-Bargains

Unique-Bargains 4Pcs 70mm Passive Radiator Speaker Black 55mm 4.5mm

SKU CH-RE6J-QR1Z0

Set of four 70 mm passive radiators with 55 mm inner diameter and 4.5 mm height for DIY speaker enclosure tuning

  • TypeSpeakers
  • Enhances deep bass by using trapped enclosure sound to excite resonance
  • Eliminates air turbulence noise and port-reflected high frequencies at high volumes
  • Reduces active driver excursion by sharing acoustic load at low frequencies
  • Four-piece pack of 70 mm outer diameter passive radiators for DIY builds
  • Durable rubber and iron construction with 55 mm inner diameter and 4.5 mm height

Passive Radiator for DIY Speaker Repair

These 70 mm passive radiators replace port tubes in sealed enclosures, letting trapped low-frequency energy excite a sympathetic resonance that extends bass output. They suit hobbyists building or repairing compact subwoofers and full-range cabinets where a conventional vent would be impractical. The rubber surround and metal centre plate mount directly to the baffle with standard hardware.

Behaviour Under Sustained Low-Frequency Drive

Because the radiator shares acoustic load with the active driver, cone excursion on the driven unit stays lower during extended bass passages, reducing thermal compression and mechanical distortion. No turbulent air noise is generated at high output since there is no port, and the absence of a vent eliminates pipe-reflection artefacts that can colour mid-range clarity.

55 mm Inner Diameter Determines Fit

The 55 mm inner aperture sets the maximum diameter of the active driver that can couple effectively with this radiator; drivers significantly larger will not load the passive cone correctly. Outer diameter is 70 mm and mounting depth is only 4.5 mm, so verify baffle cut-out and clearance before ordering.

Highlights

  • Enhances deep bass by using trapped enclosure sound to excite resonance
  • Eliminates air turbulence noise and port-reflected high frequencies at high volumes
  • Reduces active driver excursion by sharing acoustic load at low frequencies
  • Four-piece pack of 70 mm outer diameter passive radiators for DIY builds
  • Durable rubber and iron construction with 55 mm inner diameter and 4.5 mm height

Specifications

BrandUnique Bargains
TypeSpeakers

Questions about this item

How much heat or noise does a 70 mm passive radiator add when the system runs all day?

A passive radiator has no motor or amplifier, so it adds no electrical heat and produces no noise of its own; it simply moves sympathetically with the active driver.

What active driver and enclosure must I already own for these 55 mm inner-diameter radiators to function?

You need a matching active woofer and a sealed or vented cabinet sized so the radiator's 4.5 mm profile and compliance tune the low-frequency response correctly.

Will these 70 mm outer-diameter radiators integrate with an older woofer I plan to keep?

Integration depends on the older woofer's Thiele-Small parameters and the cabinet volume; the radiator's mass and compliance must be matched to that driver for proper low-frequency alignment.

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