hey prof - who remembers what’s been asked and answered?
We approached the speakers as part of the living / musc room; thus the veneer, hidden cable entries and grilles. All the later products used the grille frame and fabric as part of the design intent. The 01 had a foam grille, which was transparent enough not to matter much, but the foam did reduce diffraction a smidge. The fabric always knocks about 1/2 to 1db off the area about 4-8kHz. Many people gripe about Thiel’s being ’too bright’, while they use no grilles which indeed increases the brightness range above our intent. The 02 grille frame is counter-productive. It precedes our knowledge of diffraction and the frame increases edge diffraction. The 02 hotrod I am using to prove various technologies incorporates an elliptical rounded cabinet edge with no grille frame lip.
An exception was the later speakers such as the 3.7 and PowerPoint with perforated metal grilles, which are claimed to be ’identical’ with or without the grille. The CS3 / 3.5’s stock grilles cause mild diffraction problems, which can be minimized with modifications.