jon - you’re in good company. Most engineers align with Dr. Toole in claiming phase coherence doesn’t matter. That opinion is based on observation of double-blind testing. Note that Jim Thiel began his audio journey as one strongly in the camp of empirical / engineering driven mind-sets and choices. The coherence thing wasn’t an accident, but its existence has elements of accident.
Before introducing the 01 in 1976, we experimented with many types of transducers. Among them was a sphere covered with 1/2" tweeters with enough combined surface area to support full range reproduction. The predicted sonic nirvana didn’t happen. Over a period of months, we compared transducer types to determine our eventual platform / approach / solution. To shorten a very long and involved story, we needed a full-range coherent source as a reference - call it an inverse microphone. The Coherent Source concept began as a laboratory standard rather than a product idea.
That rightness or ease or naturalness or grace in the coherent source- was unmistakable. Coherence also unveiled myriad problems previously masked by phase scramble. A book could be written about the psycho neurology involved in interpreting sound, and the priorities and effects of "real" vs "scrambled" sound. People here have asked whether phase coherence is heard directly or part of a system of scrutiny of all factors involved in the transducer. No easy answer, but after experiencing coherence, we never looked back.
Presently I am working with the 02 as an accessible workhorse for testing and comparing various technologies. The 02 is a polarity-correct second order system (as were its successors - the entire SCS sequence.) I am building a first-order XO and adding time alignment for the 02 to address this very aspect of masking of the systems under test. Soon we’ll hear what happens when first order meets second order in the 02.
So, Jon, don’t be chagrined. Jim would have never accepted the coherence thing if he had not experienced it personally. Also, the coherence transperancy led to the need of inventing a better resistor and wire. I spent the summer of ’78 unraveling wire. Cousin Ted (our aerospace physicist) heard what we heard in the 03 prototype and suggested its similarities to low-level distortions in the Pioneer 10 / Jupiter probe communications, for which part of the solution was 6-9s (now CDA101) wire. I followed up his introduction to the project manager at ITT-NASA, and high purity, oxygen-free wire became standard in all our coils and wire from that point forward. That wire solution allowed final progress for the 03, in addition to radically changing how Jim admitted possibilities beyond his physicist / engineer comfort zone. I would call his perspective shift transformative, from quite skeptical to quite receptive. That cluster of events around first order and wire may be the defining elements of what made Thiel Thiel. Believing what we hear is crucial to real progress. Before landing on "For the Love of Music" as our first motto, another contender was "Believe It".
