If It Ain't Broke, Don't Fix It

hilde45 says "It’s whether this upgrade, on this speaker, was justified — and the evidence says no."

I must disagree.

Based on lots of experience (mine and others) Danny’s mod has the potential to improve the sound of the speakers. Note that Amir was testing an original version of the mod, and Danny subsequently adjusted it to meet some of his objections. Danny did not “double down when challenged;” he addressed Amir's concerns with a modified design, then offered that design to Dave for free.

Neither Danny nor Amir seem to have listened to the differences (although Amir had a pair, with one modified and one original). In any case you would need a modified pair to hear how sound stage and imaging are affected. The question of which version sounds better, and whether Danny’s version is an improvement, remains open.

@trumpetman48  — Fair points, worth addressing. 

You're right that Amir tested version one, and that Danny produced a revised version two. I'd concede "doubled down" was too strong — he did make some adjustments. But the video actually shows Danny's v2 measurements alongside v1, and Amir's response is essentially: these are nearly identical, so what exactly was fixed? The revision doesn't clearly address the core problems identified.

On listening: you say neither Danny nor Amir listened to the differences, and that listening is what ultimately matters. But that's precisely what Amir asked Danny to provide — a controlled listening comparison. That request is sitting unanswered. The irony is that this objection lands harder on Danny than on Amir.

And one factual correction: Amir did have a modified pair — one stock Sierra, one with Danny's crossover, tested side by side. That's the entire setup of the review.

"The question of which sounds better remains open" is doing a lot of work in your comment. It concedes all the measurement evidence and then retreats to uncertainty about listening. That's not a small concession. The measurements are not ambiguous about distortion levels, off-axis degradation, and frequency response changes. If Danny wants to overcome that evidence, the path is clear: produce a listening test.

@hilde48 — To me, measurements are a big part of the story, but only in service of “which sounds better.”  Fancy measuring systems can only take you so far. Sound preferences vary, and listening tests have their problems. But that is another discussion! 

I’m sure you are aware of Ron Bernay and his sound shed, designed and equipped for controlled listening comparisons. If the parties involved were willing to provide Ron with 2 sets of speakers, original and modified, we could get a better take on the sonic comparison. However, they would need to commit considerable time and resources, and I don’t know how high a priority this would have.

Amir’s distortion and off-axis measurements were on version 1. Danny showed distortion in his second video, and it was far lower than what Amir showed. Danny’s final off-axis measurements were virtually identical to the original. Amir, at least twice, said the measurements were “off the charts.” He could have done what Danny did and adjusted the range on his charts. 

I admit to a bias, but I would expect Danny’s modifications — crossover, tube connectors, and no-res damping, would result in noticeably better sound stage and imaging. Whether they would be more pleasing and engaging is another question.

@hilde45 

All I can say is what the hell does Danny Richie no about anything but "snake oil"!