Karlson 15 Ultra-fidelity was developed in 1951 by John E. Karlson as a hybrid with front mass-loading of the cone from a front-chamber having a broadbanding resonance chatacteristic using a tapered aperture whose slot area increases as pipe cross-sectional area decreases - backwave is part reflex and part pipe - they can exhibit pretty powerful punch on bass transients - also - they look neat :~) see Job Ulfman's site for various articles and forum

Freddy

• http://studict.student.utwente.nl/e.j.j.ulfman/