Originally Posted by dlfromcanada
so how might a Cap S or Cap S2 compare to these numbers? even though they drop below 40hz, would there not still be significant output?
Frequency response: (-6dB) 43Hz - 97kHz
Frequency range: (-10dB) 39Hz - 145Hz
Maximum SPL: (1 meter) 132dB peak
Frequency Response: 35 Hz - 135 Hz (±3 dB)
Frequency Range: 32 Hz - 135 Hz (-10 dB)
Max SPL: 135 dB
First off, those are manufacturer inflated numbers. And, you don't know what the response of those different products look like. ±3 dB can be interpreted as actually +0, -6 (as in the case of the QSC). Which is probably what they've done since they're made for 50hz + performance, and you see steep drop off below 43hz. It's actually a 4db drop in a mere 1/5 of an octave. That means it's around a -20db slope (I forget what order that is), but where it begins is anybody's guess.
Secondly, you have no idea what THD those supposed peaks were attained at. Since distortion somewhere above ~50hz begins to become easily audible, this is an important thing to quantify. Generally, home theater subs are measured at or below 10% THD on sine waves, and the CEA2010 methodology notes specific acceptable THD limits per frequency.
Third, as mike mentions, it's an apples to oranges comparison. Although you have a subjective opinion from Archaea on one of these brands of PA woofer (not really much of a sub, imho) compared to the PORTED Captivator, it's worth it to note that you won't generally want to use a PA woofer for subwoofer duties in movies. Since the most accepted standard LFE crossover frequency for HT use is at 80hz, the important part to consider is the sub's output below that. (Although, I suppose an argument could be made for 120hz since that's technically the top end of the LFE channel.)
Lastly, in the 40-80hz octave (which I was talking about in my previous reply), I'm pretty sure a ported Captivator, and possibly the sealed Captivator, will come close or match a PA offering if THD limited. Archaea thought so in the products he directly compared. Above that, sure, it's no contest. Below that, given the very steep curves of the PA kit, I know for a fact the Captivators will destroy them in output. Compare the JTR Growler, a PA "sub," to the Ported Captivator from 15-40hz, or to a Captivator S from 5-40hz, and there's also no contest.
There's a reason why essentially nobody here uses PA "subs" for subwoofer duties in movies: they're not designed for that. Sure, they might work, but why when there are better options? It's a relevant question, but this isn't generally a pro audio forum, if that's the application you're looking for.