Originally Posted by JHAz
What's not perfectly clear from the testing we've seen (ie Aholics) is how clean and how linear the ED will stay in the lower frequencies, once the EQ is added. Assuming you need to EQ up the first octave of rolloff, you're more than doubling the power required at 25 Hz versus what was used in the test, to get the device back to flat (anechoically). I'd take cautious heart from the wideapread love of these things from their owners. Cautious because I would not even trust my own repsponse to be more accurate than "better than what I have" because I am not fully familiar with the sound of a system that is flat to 20 Hz or below and has adequate dynamic capability for my listening levels. So whatever change I make, I can tell if it's better (I hope) but not whether something else might be mo betta.
I'm inclined to think that the a7s-450 would excel in this area (over and above its competition) based on the its ample headroom from the 18in driver and 1300W amp. As you use the EQ to level out the FR, because of its headroom, it would be able to maintain its output capabilities because it could still serve up the power requirements needed from the EQ adjustments.
Whereas other subs with less headroom, would drop output and cause earlier audible distortion and decreased SQ.
So, back to FR matching; assuming you FR match to a flat response via EQ, some subs will be more adversely affected in both output, extension and SQ based on its headroom. Those subs with more headroom could handle EQ better given a certain output, and therefore be able to maintain a flat response with deep extension at high output levels.
Since most owners will apply some sort of EQ to their sub (Audyssey, SMS-1, etc.) to smooth the response, the subs ability to handle EQ is a critical piece to the puzzle and often overlooked.
My reasoning behind this is somewhat anecdotal, but I've experienced this with the a7s-450; During the Hulk sound cannon scene, I was able to hit 118db at my LP without any EQ. I then engaged Audyssey (which starts boosting at 16hz to a boost of +9db at 10hz) and remeasured my output. It was still 118db.
I just posted a thread
about headroom/output to help flush my understanding of this (hopefully someone chimes in). It intuitively makes sense, just not sure of the science behind it. If you have any thoughts around this, please post it there as to not derail this thread further...