I understand every single thing you said in your last post Josh ---
I think what I'm failing to communicate in my devil's advocate role is that even if you have more dyamic SPL capability --- you loose frequency response accuracy to the original source as soon as you pass that threshold of 102db at 20hz on the Epik Empire for anything that requires greater than 102dB at 20hz from the source material. Sure you have 22dB left of dynamic headroom, but that headroom comes at the expense of frequency response accuracy. Because that 22dB of headroom is only available increasingly up to 125hz -- not anywhere near 20hz.
If you want the extra SPL it is at the expense of accurate flat frequency response --- that's a choice -- that's all I'm trying to say. Some may not want that choice.
When the SVS PB12-NSD caps out at max spl - won't it retain a more flat frequency response as it nears the limits? All I'm saying is some may prefer that. It's sort of capping the subwoofer volume more at an ideal frequency response...
how to explain...???
It's a dumb example but Black Eyed Peas Boom Boom Pow song was actually the song that oppened my eyes to a clear audible definitive example of a flat frequency response.
On most every sub I've ever heard that song -- as heard almost anywhere you go the boom boom pow bass notes (distinct different frequency bass notes) sound different volume levels relative to each other. On one system you might have a boom BOOM
POW On another system you might have a boom
BOOM pow, a third may be boom boom
POW. When you have a flat frequency response and listen to this song all the bass notes (despite being at very different frequencies sound the same volume). When you turn off your EQ and listen to the same song some of the bass notes are very emphasized compared to the others. It's a good example of how frquency response can effect music listening.
Sure the Epik Empire would get louder on that song, but the emphasis would be weighted towards the upper bass notes. It would gradually happen as you increased the volume beyond the threshold of each's notes max capability on something like the Epik Empire. After knowing/hearing what it's supposed to sound like (with even spl on each bass note) it would sound weird on the Epik as you approaced the Epik's limits. The SVS PB-12 NSD would maintain a more even spl weighting, more faithful to the original source frequency response/sound on each note as you neared it's (lesser overall) limits.
Granted if you kept the Epik at the same overal volume (less 1 dB) you'd have the same experience, but who doesn't turn their subs up until they hit the limits.
The true limits of the SVS just would be a bit more accurate to the source material yes? (at admitedly much less volume)
Probably a terrible example but it's the best I have to illustrate my thoughts.
It be a much easier argument if the $800 pb-nsd put out 110db at 20hz. Would you rather have 110 to 116db across the spectrum from 20hz to 125hz or 102 to 124db range across that same spectrum. That's more an example of what would illustrate the point.
Another example of choosing a flat frequency response out of the box is a specific usecase where there was no eq available and the sub was used nearfield or in a small room. I recently purchased a Jamo 650 Sub precisely because of its unusually flat frequency response for the sale pricepoint. I have a cheap onkyo receiver upstairs with no Audyssey nor other EQ functionality for use in a small living room. The Jamo will likely meet my specific needs more than the Epik Legend because EQ is unavailable to me on that system without spending addiitional dollars. I trust the Jamo's more native flat frequency response to likely end up being more accurate in my room. (admitedly nulls and modes may not cooperate - but i'll figure that out with the omnimic) I don't need the extra SPL the Epik Legend would offer, and so I'll choose the flatter frequency response because I lack the ability to EQ the top off the Legend's design choice for this secondary system. Someone who is using the sub as a computer based subwoofer and doesn't have something like jriver for custom tailored EQ- might make a similar choice. If you don't apply EQ to a subwoofer design like the Epik, you are STILL going to end up with a non flat, (non accurate to source) response even at low volumes, because of the natural non eq'ed frequency response out of the box - with no eq applied.
Edited by Archaea - 8/24/12 at 8:53am
I'd really like to hear the XS15! Would be cool if you wind up bringing it to the meet to compare to the Hsu ULS and maybe even the Empires? We should set them up for a bit with my Maggie MMGs. 
