maybe our taste are vastly different... many many people hate DD... and for the same reason, yet the drivers i have used i know there limits and what they where designed to do and what the can do... so i learned to alter some things to aid the woofer in different areas that where lacking...
for instance everyone is lead to believe that DDs need huge boxes... that couldn't be further from the truth... 9515s work in smaller boxes, but they become VERY irritated if you don't do one thing... adjust port area.. its a MUST with a sub using such a stiff suspension...
i tried my 2512a is a couple boxes and the output is staggering in the boxes recommended by DD... the woofers designed for larger boxes and higher tunes but they can be altered...
1.75 tuned to 28 with 40in^2 of port area... lowend was bowl-moving and high frequency extension didn't suffer one bit...no longer was it peaky and one noteish.. it became more defined and sounded more natural..there was one huge sacrifice though, efficiency... it went threw the floor and i could find its thermal limit long before its mechanical limit.. there are a great deal of things you can do with a woofer once you know it limits and boundaries.. i will admit that the 35 and 9500 are more SPL oriented.. thing is they too can sound great in there useable bandwidth... the 9500 is awesome on fast paced music. like techno and metal/rock which lowend extension isn't below 40hz...sure there overdamped but there are ways to make them very mild.. i have used them quite a bit and i love there products... i don't think they sound bad cause they don't but there not what amny people like to call SQ woofers.. simply because of the l higher tunes and over damped/dry sound and limited lowend....
if you find yourself thinking that lower FS woofers and small sealed boxes sound better, your probably lending to a specific damping and type of sound you perfer... which is perfectly fine