Added a pair to a large installed system for around $400 each. Bought from a local Peavey rep.
Peavey has a winner with the Impulse subs. It's basically an Impulse enclosure with no tweeter, just a Black Widow woofer. But what a woofer!
It's rated at 1000W program (!), but I'd only recommend that outside, in a large area. For example, the pair being reviewed here are hanging in a high school gym, connected to a 400W amp. Light the system up with a hip-hop CD, and you can literally shake the bleachers!
Another nice feature is the built-in low-pass filter. No more fiddling with crossovers and custom wiring harnesses. Just plug it in (even daisy-chained from your tops) and ROCK!
Most subs are all about the thump. Sure it doesn't sound that great, but you get the cool effect to complement your mids. The impulse is different: it SOUNDS GOOD! In fact, you don't really hear the excessive bass, you feel it.
The low-pass filter is only on the 1/4in input. It would be nice if the Speakon was filtered too, just for ease of use. Granted, that's a pretty weak complaint. These subs are just that good.
As subs go, this one is pocket-sized. The ones I bought are hanging from the ceiling, but I wouldn't mind hauling a couple of these around in my portable PA--they're that small and light! The injection-molded case even has fly-points, handle, and pole-mount built right in so you can use it however you see fit.
The Impulse has a Speakon input, plus a pair of paralleled 1/4in jacks for daisy-chaining goodness.
Injection molding appears to be the cabinet of the future, and I welcome it! I highly doubt you can abuse these to the point of serious damage, even with road use. And if you do, the woofers are field-rebuildable for a quick and easy fix.
If you need some serious thump in your small to mid-size PA system, don't bother shopping. Get Peavey Impulse subs. They're definitely not the cheapest subs out there, but they're light, versatile, and ridiculously tough. Throw in loud with a clean, tight sound and you've got every soundman's "dream features" list.