Simplexx 18 Home Theater Subwoofer Kit

Simplexx 15 HT Driver
Dayton RSS390HO
Dayton RSS390HF
Price: USD $394.95
  • Description

Simplexx 18in DIY Subwoofer Kits

The Simplexx Series by Bill Fitzmaurice are the perfect combination
of performance and ease of construction

SpeakerHardware kits make them a painless start for the beginning builder, or the experienced one who needs simple high performing speakers.

  • Simplexx cabs feature braced half-inch plywood construction, for better performance with lighter weight than commercial cabs.
  • All feature corner located ports, for stronger construction with less weight than round or slot ports
  • Corner ports also sound better than round or slot ports, as their placement equalizes air pressure inside the cabinet, preventing cone rock at high levels.
  • These cabs aren’t difficult to build, but they still feature engineering that even ‘boutique’ cabs can’t lay claim to.


Simplexx 18 DIY Subwoofer Speaker Kits

  • Response:  25-250
  • Dimensions: 22inw x 27inh x 22ind
  • Weight: Approx 70-75lbs
    dependent on driver and hardware.

Complete details and plans are available from

Kit Contents

Simplexx 18 DIY Subwoofer Deluxe Kit Includes:

  • 2 Drivers available, RSS390ho for ported, or HF for sealed
  • Every nut, bolt, screw and washer to complete your cab.  All hardware and screws are black
  • Gasket Tape
  • 1 tube PL Constuction Adhesive
  • Dish with gasket, includes jacks with screws/bolts and wire connectors, choose your style
  • Precut Plywood is not in this kit. Available separately
  •  All parts are tested and confirmed by the SpeakerHardware shop to fit a Simplexx.

Response Graphs

Simplexx 18 subwoofer


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Shipping & Inventory Update

We are doing our best to get our products out to you in a timely, safe fashion. Expect partial shipments, as our inventory allows. The entire speaker industry is experiencing parts shortages, lead times will be long. 

Please email about any order that includes drivers for availability. 

The situation is changing too fast for me to keep the out of stocks listings current. The balance of any order will be sent as soon as we have product available.

As you may know, plywood prices are skyrocketing. We will strive to keep increases to minimum amounts to cover our changing costs. Availability is becoming an issue also. Business is booming, and flat pack and shop built orders are once again stretching lead times.

Expect at a minimum of 3 weeks for any shop built order.