Black Dahlia Acoustics - Loudspeaker Kit Plans  
The BassZilla Loudspeaker Kit Plans

Loudspeaker Kit Designs by Dick Olsher

The BassZilla Kit Plans

Updated November 2008

The BassZilla is an ultra high-efficiency (96 98 dB 1W/1m) loudspeaker family designed by Dick Olsher to facilitate the ultimate listening experience with low-power single-ended triode (SET) amplifiers. Its primary reason for being is to coax the most enjoyable musical experience possible from full-range and wide-range driver technology. The BassZilla combines a high-efficiency, direct-radiator, bass module with a full-range twin-cone or wide-range paper driver that is operated in an open baffle as a dipole radiator. The BassZilla's 15-inch woofer provides the foundation for the full-range driver, not only sonically, but also physically, as the open baffle sits on top of the bass module.

Several incarnations or flavors of the BassZilla are described. The original designs preserve the coherency of the full-range driver by operating it full range without any high-pass electrical filters. However, a passive EQ network is used to deal with the inevitable break-up modes of full-range paper drivers. Later versions include the Aurum Cantus G2Si or G2 ribbon tweeter to extend and refine the upper octaves. Parts cost for the Platinum Edition Mk2 (which uses the Fostex 208 Sigma wide range driver), exclusive of the cabinet, is estimated to be in the range of US$1,300 US$1,600 per pair depending on the quality of the crossover network parts. The cost-no-object version is based on the Lowther DX4, and exclusive of cabinetry, its estimated parts cost is around $3,000 per pair. Commercial sources for drivers and parts are given at the end of the kit plans. Note that Madisound Speaker Components now offers fully assembled crossover boards for both versions of the BassZilla, as well as all parts for the Fostex system. These are fairly easy to build kits, suitable for even the Do-it-yourselfer with moderate woodworking skills.

Note: The BassZilla kit plans for the Lowther full range were updated during October 2003 to accommodate the new production Lowther DX4.


Black Dahlia Acoustics, Ltd. is committed to offering the loudspeaker DIY hobbyist the opportunity of enjoying great sounding speakers, at a fraction of retail cost. I have been designing speaker kits since the early 80s, with my first design (the Dahlia) being published in Stereophile Magazine in 1987. All of my public domain designs, from which I have never derived any royalties, may be accessed at Dick Olsher's Audio Mecca at

I am particularly proud of the BassZilla Kit plans now on sale at the HiFi Store. This loudspeaker family brings out the best possible sound from twin-cone full-range and wide-range driver technology, without subjecting oneself to any of the traditional problems such as lack of bass. Now you can have your sonic cake and eat it too!


Dick Olsher
Black Dahlia Acoustics, Ltd.

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