But, the big thing I noticed in terms of sound quality was how much tighter and deeper the sealed subs went. The thing with the ported subs is that below their tuning frequency the output will drop off drastically, but sealed subs tend to have a smoother roll-off.
That's true, however you're forgetting to consider that
any kind of rolloff in audible frequencies is generally undesirable.
That's why you go with a ported sub that can be tuned around 14-16hz and is big enough to accomodate a port that won't chuff at that tuning frequency(350-600L of enclosure volume or so with an 8 or 10 inch port tuned low). It'll give you virtually flat anechoic frequency response up to around an octave above the tuning frequency, then a very, very shallow rolloff to the tuning frequency after that, and anything below the tuning frequency is likely so low that the steep rolloff is inconsequential. And you'd get way better efficiency, meaning it will be able to go louder than a sealed sub, as well as requiring less EQ (only EQ we're talking about is for in-room nodes, not for the sub's actual frequency response).
For example, here's a modeled SPL response for a certain driver in a couple different enclosures (1000w of power, 3 m away) (yes, i do realize all drivers do model differently but this driver is fairly versatile)
Green is 490l box with a port tuned to 14 hz and a 7hz HPF (actually likely unessessary anyways because of how little content there is down there... I really doubt i'll ever be sending a 9 hz /1000w signal to my sub, it's safe to say)
Purple is 490l box with two 18" PR tuned to 14hz and a 12hz HPF - this will be physically smaller than the green box because there's no internal port volume to consider.
Red is 490l sealed enclosure
Pink is 130l sealed enclosure
Blue is 130l box with a port tuned to a more commercially typical 25 hz with a HPF thrown in at 10hz.
So yes, for smaller boxes, sealed works smoother, as you can see, the pink line has a smoother rolloff than the blue line, which will make notes in the "musical" subwoofer range of 25-80hz or so range sound a bit better. Of course, that as you can see, the ported sub is "louder" everywhere within that range, so an EQ to make it quieter would actually mean you're using less power to get the same sort of sound as the sealed sub. The only other argument someone might have after that would be that their sealed sub has more so-called punch because relative to lower frequencies, it's got more volume in the "punch" frequencies, whereas the ported may be "too loud" and someone may find themselves turning the volume down and taking away the "punch". That, though, is coloration, and the green line seems to have the least coloration out of any sub, followed closely by the purple line which i may not have modeled properly because it's a PR build.
But if WAF or roomspace isn't an issue (or you can work around those things), then a large ported box has the least of the audible rolloff you speak of. Anything below 18-20hz is inaudible; it's tactile anyways, so a steep rolloff starting at 15hz ain't a bad thing, especially when you consider how room gain will come into play at these sort of frequencies. Be honest, that green line is the most impressive out of the five, isn't it?.
Now anyways back to OP who's looking at 2x eD A5-350 and 2x eD A7s-450.. Even ignoring all that i've said above, as I'm sure both are really good subs, I don'y think you could go wrong with either, but that said, I think I'd ultimately take an 18" driver with 1300w RMS amp over a 15 with a 500w amp... Worst comes to worse, just take a router to it and make your own port and you'll have the best of both worlds (er... maybe... I'd model it first lol)
You can't deny the difference in raw displacement, and considering you're grabbing two, I bet you'd be getting quality sound down to 15-16hz even with a sealed.
