Posted 07 August 2012 - 09:32 PM
The DLS Nordica looks good..I was looking into that sub myself a while back. I'm not sure how it measures in terms of distortion etc, but for an 'SQ focussed' sub it definately looks to have some pretty good output potential. Good sensitivity (if the listed specs are truly 1w/1m), good displacement, solid power handling, and models out really nicely. When I was looking at potential replacements before the Nordica came out second to the IDMAX in terms of SQ subs that looked like they could really take a pounding...I think it may have potential if the soud quality is as good as DLS claims.
The previous generation IDQ was a proven performer - I've seen measurements and i was a legitimate low distorton subwoofer, up there with the Peerless XXLS. The new version looks great, but whether i will actually perform as good as the old one is anyones guess. It looks like a completely different design to the previous gen model so there is no evidence to suggest it will peform at the same level outside of Image Dynamic's own claims (and obviously they're going to say it's better). My concern with the IDQ is output - from what I recall the old one had quite high sensitivity, but I think this new one is down aroud 85dB which is a bit below average for a 12". When you have limited power available (and want to be able to play loud) the last thing you want is a sub with modest sensitivity.
The ARC12 I can't really comment a lot on - unfortuantely in the above links the specs provided are sparse to say the least . It doesn't specify how the sensitivity is measured (2.83V vs 1W), doesn't specify xmax and the cone area (31.4m?) makes no sense at all. I would suggest the 89dB sensitivity listed would be at 2.83V/1m (measured on a 4ohm load) unless proven otherwise, because that would convert to about 86dB 1w/1m which is about right for a 12" subwoofer. If I'm right then that's about average sensitivity for a 12" woofer, and should drive slightly (if not much ) louder then the IDQ given the 300W you have available.
The Black 12 I can say even less about, because they specify no real useful information at all on that link. If you can throw me something with a little more information then I can tell you a lot more, but the specifications listed on that page are too sparse to really be useful.
If output is what you're after and space is not so big an issue, I'd also seriously considering stepping outside the square and looking at the option of either a single 15" (like an SB Acoustics SB42FHC75) or a pair of modestly priced but nice sounding 12's (such as the Peerless XXLS). Either option is going to generally give you significantly higher senstiivity then a single 12" sub, and when you have limited power available that is critical to achieving high output potential. Both options will typically give you better sound quality as well, because higher displacement means that individual subs don't need to work as hard, which means less distortion and cleaner sound.
Don't fall for the myth that smaller drivers are more accurate either - a 15" with a good motor (like a JBL GTO) can play flat to 800hz and beyond, while a not-so-good 8" sub with a mediocre motor may struggle to play clean up to 80hz.
Back to output - just to give an example, the sensitivity on that SB Acoustics 15" is about 90dB @ 1w/1m. This is roughly 3dB-4dB higher then the sensitivity of an average 12" sub, and a gain of 3dB output equates to a doubling of input power. That means this SB42 would theoretically go about as loud off 300W as an average 12" would go off 600W, so if loud-and-clear is what you want, it's a legitimate option to consider.
Using a pair of low distortion 12's can also give you a similar effect. You essentially gain +3dB in sensitivity by adding a second driver, so a pair of 12's off 300W will also give you about as much output as a single 12" (of similar sensitivity) running off 600W.