Front plate on the Stealth :
Difficult to know whether or not there is a front volume vent beneath the tuning cover.
Also, not sure whether or not the hole at the top of the earcup is covered by the pads once they're glued.
Since DCA headphones are so leakage intolerant, first and foremost we'd need to know what the actual response is on the head of people who report a lack of "impact". Everything else is a complete and utter moot point in comparison.
He probably wouldn't word it this way, but if Sean Olive expressed his disappointment that his Stealth lacks "impact", there could be a fairly straightforward explanation for it : Or not, if his definition of "impact" is unrelated to that phenomenon.
Even in the case of good leakage tolerance, if the FR remains different throughout the spectrum, it may still influence how bass is perceived, so...
Resolve, who published such on-head measurements, seems to appreciate Focal's open HPs for "impact", while criticising DCA headphones in that regard, despite seemingly getting a decent response out of them at lower frequencies, so in his case anything related to static pressure (which Focal's open HPs won't be capable of affecting - that's probably the case for most headphones anyway) most likely has nothing to do with his impressions.
Given that we still don't know whatever "impact" means to various people, it's a subject that's bound to lead nowhere. We'd need an operational definition of it before starting to test for it in the first place.
Dan Clark Audio Stealth - Closed-back High-End Headphones Redefined - Headphone & Earphone Audio & Reviews
Dan Clark has done the seemingly impossible in making a pair of high-end headphones that re-define what is possible with portable audio.
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Also, not sure whether or not the hole at the top of the earcup is covered by the pads once they're glued.
I believe it's this static pressure reduction (as well as reduced infrasound response above the 0 Hz of static pressure) that results in a reduction in perceived bass impact, through several potential mechanisms, related to physiological changes in the auditory system caused by static pressure (see for example here and here), but also amplitude modulation of higher 20Hz+ sound by infrasound, as described in the paper I linked to in a previous comment.
Since DCA headphones are so leakage intolerant, first and foremost we'd need to know what the actual response is on the head of people who report a lack of "impact". Everything else is a complete and utter moot point in comparison.
He probably wouldn't word it this way, but if Sean Olive expressed his disappointment that his Stealth lacks "impact", there could be a fairly straightforward explanation for it : Or not, if his definition of "impact" is unrelated to that phenomenon.
Even in the case of good leakage tolerance, if the FR remains different throughout the spectrum, it may still influence how bass is perceived, so...
Resolve, who published such on-head measurements, seems to appreciate Focal's open HPs for "impact", while criticising DCA headphones in that regard, despite seemingly getting a decent response out of them at lower frequencies, so in his case anything related to static pressure (which Focal's open HPs won't be capable of affecting - that's probably the case for most headphones anyway) most likely has nothing to do with his impressions.
Given that we still don't know whatever "impact" means to various people, it's a subject that's bound to lead nowhere. We'd need an operational definition of it before starting to test for it in the first place.