Thiel Owners

Happy Friday! All

thielrules - as I see it, the output of the port is a full cycle behind the output of the upper drivers, with 4th order (24dB/octave) slopes induced by the physical / mechanical interaction of the resonating port (no electronics involved.) Since I think that 4th order slopes maintain phase linearity, the only non-coherence would be in the time domain, where the frequencies covered by the port would emanate one cycle behind (but in phase). My calculation says that lowest tone centered on 38Hz (port peak output) would sound like it comes from 30' behind the speaker.Above 50Hz (the -3dB/half power crosspoint) the output becomes dominated by the woofer which is in-plane and therefore in-time with the upper signal.

The lowest note of a bass is about 40Hz, and most of its information is above that 50Hz crosspoint. So, I'm not surprised if many people can't distinguish between ported and sealed bass. Also, your DSP solution that further minimizes slight phase discrepancies in Jim's original analog filters, does introduce a digital conversion as well as some pre-ringing (which you have minimized.) I am one of those folks who is sensitive to pre-ringing, so I might choose different trade-offs than you do.
Remember that most modern speakers admit these 360° / full rotation phase shifts at every crossover point, where there is lots of musical information. The common call is that "it can't be heard". I suspect most Thiel fans prefer it not be there, even if their ear-brain is deemed to be able to ignore it.

@thielrules  I'm not sure many of us could differentiate a 'coherent source' Thiel from a 'conventional' speaker with standard A/B testing (blind or not) over the course of an evening.  As I related a few months ago, I bought Thiels (2.3 then 2.4) as they checked so many boxes for both design and immediate sonics.  Their coherence was mostly an academic advantage to this engineer.  It was only after a few months of listening only to a good non-coherent speaker in place of 20 years of Thiels in my familiar acoustics and electronics that reinserting the CS2.4 into my system created a profound psycho-acoustic improvement.

@tomthiel  OK, I'll accept that, that the ported bass results in a fixed 1-cycle lag from the radiator, hence phase coherence remains intact throughout the speaker's entire bandwidth.  And time coherence is only impacted in the lowest frequencies where the passive radiator is most active, below 100Hz in my 2.4 instance.  And yes that's a helluva lot better than most other speakers that go through all sorts of phase and timing shifts at each crossover point, as Stereopile plots show, dismissed as 'optimal crossover design' as 'each driver smoothly hands off to the next.'

Tom, we are not in disagreement. The pre-ringing is only a concern if I use linear filters to reduce the phase differences in the xo range. With digital minimum filters this is no concern but the phase differences are harder to control. I don't get it why dsp does not get more support. It is the easiest way to approach objective transparency and at the same time dial in any frequency or xo characteristic that you may subjectively desire. Instead of experimenting with different cables, amps, or any other hardware, you simply change some settings and switch back and forth to hear the differences. 

thielrules - I understand the trade-off between linear and minimum plusses and minuses. Regarding the DSP solution, that's a realm that is morphing in real time. Even at the very high end, digitization still brings its own set of potential problems.  Digital circuitry is noisy and requires careful isolation from analog. Assuming you can manage all that and get stellar results, there is the matter of different skill sets. Of course in Thiel Audio's day, the realm didn't exist, or was still in its infancy and adolescence. Jim developed his tricks and his niche firmly in the analog sphere, and nurtured and grew those skills over his whole career. I am committed to consolidating that legacy for its stability into the future.

I am pleased that you are applying digital solutions to the design, but such an undertaking beyond DIY, would take a concerted effort to make it so.