Loudspeaker Designs and Articles for the DIY Enthusiast
Driver Selection Process

The woofer: Aura NS6-255-8A

I liked the low price of the Aura NS6-255-8A, and obtained several for evaluation. While their motor systems appear relatively simple, they make up for it in
consistency. The first six measured virtually identically, so I have to give high marks to Aura for good quality control. I could have done without the ‘classical
look’ front mounted gasket, but all and all these exhibit a very high value for the price. This is bargain basement pricing for a neodymium magnet driver.
They can play lower but take much large enclosures to do it, and max SPL suffers as a consequence. They may lend themselves to open baffle designs.   
The tweeter: Vifa BS25SC06-04

I needed a tweeter with a very high sensitivity to mate up with the multiple woofers, and in keeping with the high value design goal, choose the Vifa
BC25SC06-04. This little horn loaded neodymium soft dome met all the requirements, and measures pretty decently as well. The horn loading helps with the
power response around the crossover frequency. The sensitivity of this tweeter is quite high at 96 dB  / 2.83v /1 meter and provided a near perfect match
with the sensitivity of the 2 paralleled woofer pairs of near 100 dB. The harmonic distortion plots suggested a crossover of 2.5K would quite feasible, and for
the going price, they are a bargain.  
Sten II
Links to:

Main / Design Goals

Driver Selection

Cabinet Construction

Crossover Design


Listening Impressions
Big sound for a very small
price. Suggested for
bookshelf or near-wall /
on-wall applications.