Nice to see all these Thiel pixels! My (memory of) 38" ear height relates to average seated ears. I don't know what height was assumed after mid 90s, but probably the same. Measurement distance is 3 meters with an assumption of that as minimum listener distance. Notice how little tilt would be required to adjust for spikes at 10' to 12' assumed distance. Rob, or anyone, please correct me if 38" is incorrect. One day soon I will have spectrum analysis equipment to verify such matters going forward.
Regarding measurement methods. Thiel did have a SERIOUS anechoic chamber at 20' high x 30' wide x 50' long (approx). Room reflections shelve at 200 hz. We began life balancing for 2db down below 200 hz and above 200 hz flat out to 20K+. That target was modified over the years to conform to general industry practice, AGAINST Jim's wish for FLAT is FACT, not opinion!
Jim had designed and built an interrupted pulse stepped signal generator which fed 1/3 octave pulses to the speaker (6' off the ground), @ 1 pulse acceleration, 1 pulse measured -calculated room decay before next pulse cycle 1/3 octave higher. Pulse sweep was 20Hz to 30kHz.
Jim also used rapid full-range sweep above 200Hz and noise burst / Fast Fourier Transforms, before such stuff was available on PCs. Oh, there weren't any PCs when Jim developed these tools.
All those measurements were correlated with free space measurements (speaker suspended from edge of roof 20' above ground) and half space (ground plane) with speaker firing into open space (woofer bounce) and firing down-angled with mic at position of first ground bounce, and buried in the sandbox for infinite baffle response to isolate edge diffraction effects. All these measurements converged into a well-rounded picture of frequency, time and power response where we knew how the speaker would interact with a room. Thiel believed that speakers should do their job of flat response including edge diffraction, and the room must be massaged to do its job of even support. I don't know where these presumptions landed by Jim's death in 2009. An earlier commentator above shed light on that; Jim may have migrated away from flat to align with generally held expectations. I always wanted to garner consistent assumptions from the recording engineering community, but we couldn't find consensus there. Everybody second-guesses everybody else!
Larry Staples was an early Thiel pioneering dealer in Louisville. He and others like him forged a new path in audio which became known as "high end". Hello Larry.
