To eliminate a wooly bass I had to eliminate enclosure distortion. I reinforced the insides of the A7 bass cabinets with 25mm x 50mm beams screwed and glued narrow end to floor and sides in irregular patterns, added sheep wool insulation to floor and sides and back, also packed back of horns with same. To stop ringing in the treble, the two 511B metal high frequency horns were replaced by two rows of five wooden exponential horns built by Markus Klug in Germany. The stock Altec N501-8A crossovers were changed to Pete Riggle "Hiraga" style units that use NOS oil-filled caps instead of mylar.
