Rules - by "just as good", I believe Warren refers to sound quality. See this audiogon thread regarding some pros and cons.
https://forum.audiogon.com/discussions/thiel-3-5-equalizer-advice
Even if the Thiel EQ or Golden Flutes alternative were completely sonically transparent, we are left with the problem of extreme woofer and lower midrange excursion which introduces various distortions including Doppler Shift and large excursion non-linearities.
No matter where you land on this controversy, it certainly represents a major historical shift away from low-order, sealed bass tuning to higher-order, ported tuning with the passive radiator. Originally Thiel speakers were going to use ports and passives in the 1 and 2 series, and equalizers and/or active woofer or subwoofers in the 3 and higher series. Jim struggled with the issue, felt some resentment with what sometimes seemed un or thinly founded critique and lack of appreciation for what the EQ brought to the table.
I personally felt that the passive radiators in the upper models, even though superbly executed, gave up a unique signature bass performance. A matter of history interjects itself: in the 70 and 80 there was less knowledge and willingness to solve room resonance issues. The speakers were often blamed for room problems, since they went so powerfully deep.
Warren - As you know, I consider the 03, 03a, CS3 and CS3.5 to be cognitively the same design. As such, as replacement drivers and solutions are developed for the 3.5, they will be applicable to the other models in the early 3 series. By the way, I believe those early 3 cabinets were the quietest that Thiel ever produced and, with some added bracing and SoftLaunch baffle tweaking, can be brought nicely into the 21st century. The grille frames suck more than I realized at the time. They're getting attention. Also, the modern grille fabric seems better than nothing and does not alter the frequency response appreciably if at all.
https://forum.audiogon.com/discussions/thiel-3-5-equalizer-advice
Even if the Thiel EQ or Golden Flutes alternative were completely sonically transparent, we are left with the problem of extreme woofer and lower midrange excursion which introduces various distortions including Doppler Shift and large excursion non-linearities.
No matter where you land on this controversy, it certainly represents a major historical shift away from low-order, sealed bass tuning to higher-order, ported tuning with the passive radiator. Originally Thiel speakers were going to use ports and passives in the 1 and 2 series, and equalizers and/or active woofer or subwoofers in the 3 and higher series. Jim struggled with the issue, felt some resentment with what sometimes seemed un or thinly founded critique and lack of appreciation for what the EQ brought to the table.
I personally felt that the passive radiators in the upper models, even though superbly executed, gave up a unique signature bass performance. A matter of history interjects itself: in the 70 and 80 there was less knowledge and willingness to solve room resonance issues. The speakers were often blamed for room problems, since they went so powerfully deep.
Warren - As you know, I consider the 03, 03a, CS3 and CS3.5 to be cognitively the same design. As such, as replacement drivers and solutions are developed for the 3.5, they will be applicable to the other models in the early 3 series. By the way, I believe those early 3 cabinets were the quietest that Thiel ever produced and, with some added bracing and SoftLaunch baffle tweaking, can be brought nicely into the 21st century. The grille frames suck more than I realized at the time. They're getting attention. Also, the modern grille fabric seems better than nothing and does not alter the frequency response appreciably if at all.