DD Audio 715d D4 subwoofer 15" (380 mm).

DD Audio Redline 715d D4 subwoofer 15" (380 mm).

Completely renewed Redline 700-series offers many advantages over the older design. 
Redesigned frames and suspension geometry allow lower Fs and greater excursion potential. 

These two things combined give you a LOT OF BASS especially at lower frequencies. Revised voice coils have increased thermal handling. 
These features give you smoother response, more output with same amplifiers and more power handling. 
Aesthetic improvements are also made. Red double stitching no more exists, redline is now visible between cone and thermoformed multilayer surround. 
Dustcap-logo is made of reflective foil layer. All cones and dustcaps have now black matte finish. 
Alucast frames have DD branding. 

Triple ventilation of voice coil, laminated multiple spiders and extended pole pieces that have made DD subwoofers so outstanding, are still present in these new models. 

Redline 700-series subwoofers have 3″ voice coils available in dual 2 or 4 ohms. 
Available sizes are 10″, 12″ and 15″