Build the ultimate subwoofer capable of moving over six and a half liters of air with each stroke! Truly not for the faint of heart! This kit includes a 4 cubic foot CNC-machined subwoofer cabinet and the Dayton Audio UMII18-22 18" subwoofer.

• 18" Ultimax II driver with over 2" of total cone travel to move up to 6-1/2 liters of air
• 4.0 cubic foot CNC-cut cabinet made of 3/4" MDF panels with a 1-1/2" thick front baffle
• Internal bracing ties every side together for minimal panel resonance
• Rabbeted corners and internal dado joints makes assembly easier than ever
• Excellent sealed low frequency extension: F3 = 35 Hz and F10 = 21 Hz

This compact cabinet is designed specifically for the Dayton Audio 18" Ultimax II subwoofer. This 4 ft³ enclosure uses precision CNC cut 3/4" MFD panels to ensure simple assembly and a rigid cabinet. The interlocking bracing ties every side together to keep panel resonance to a minimum. In addition, the stacked front baffle is 1-1/2" thick giving you and extremely solid surface to install the heavy Ultimax II 18" driver.

The Ultimax II 18" plays clean, low, fast, and LOUD. Designed to excel in compact sealed enclosures, it features an ultra-powerful stack of high-grade ferrite ceramic magnets for strong motor force and exceptional control. With an aluminum shorting ring and huge cap, inductance is kept to a minimum to give you extremely low distortion, “faster”-sounding bass response, and perfect magnetic symmetry. Featuring a carbon fiber cone, rigid cast aluminum frame, dual spiders, 3" flat wound voice coil, dual shorting rings, extensive venting, and an FEA optimized motor, this driver is built for high SPL, ultra-low bass extension with minimal distortion.