I'd like to see the g25HP tested by data-bass actually. If their website claims are anything like how the FV25HP ended up, then clearly the cap4000/s2 would best it in basically every scenario. The fv25hp ended up showing compression starting at it's 105dB sweep, albeit very minimal, but by the 115dB sweep, it's really starting to be there.
Rythmic also shows response from 12-200hz on the site for both the g25 and the f25, but doesn't state a +/- with that spec. Tested, the f25 has almost an 11dB rolloff in it's response from 150hz down to 17hz, whereas the cap4000 is +/- 3dB over it's own usable range (10.5hz-125hz). The cap also does this with close to 6dB more headroom in max long term output and CEA bursts over the majority of the usable range.
Bottom line, it would take two
f25hp's to get even close to the cap4000, and you'd still be pushing it. If the g25 spec fall in line with the discrepancies of the f25 (not saying necessarily that they do,) the argument is the g25 being sealed would have even MORE rolloff than the ported.
All this being said, I can see why people think the f25, and g25 for that matter rock. A sloping bass response like that sound really awesome for music, and likely pair up well with room gain to create an overall flat response once it's over and one with. This is the exact reason I like how the skhorn sounds so much, it follows much of the same response curve.... but, with 14dB more headroom