The NaO U-frame woofer system is an excellent compliment for any smaller speaker or speaker with challenged low frequency response. At the right the NaO U-frame woofer is shown with the Quad 63 ELS speaker. In such an application not only does the woofer provide deep, articulate bass response but also unloads the main speaker from low frequency duty resulting in improved midrange clarity and definition. The NaO U-frame woofer system is also an ideal companion to the Magnepan MMG speaker system.
The NaO U-frame woofer system consists of an active, stereo crossover/equalization unit which provides the necessary transition between the main speaker and the woofer, and also provides the necessary equalization to extend the woofer's response to 25 Hz. The system is built around the Peerless 10" XXLS 830843 woofer. This woofer 25 Hz fs and Qts sufficiently close to 0.5 (Qts = 0.44) make it suitable for very straightforward equalization following the approach discussed in the section on Gradient Woofer Equalization, for Qts of 0.5 or greater with acceptable fs. For this application the 4th order high pass response was chosen insuring protection from over excursion due to excessive equalization below fs when other equalization approaches are implemented. This, combined with a quasi 4th order Linkwitz/Riley crossover between the main speaker and the woofer provide a seamless transition.
The NaO U-frame woofer system is sold as a DIY project in several formats: plans plus the require printed circuit boards (PCBs); plans with assembled and tested PCBs; or plans with completely assembled active crossover. The PCBs used are the same as those used in the Mini active crossover. The construction of the U-frame is left to the builder being the most cost effective approach. The plans include complete U-frame construction details including the required damping. Please see the Products page for complete pricing options.
Plans and PCBs for Peerless 10" XXLS woofer system: $155 U + 3% PayPal fee.