Let's look at some absorption reports. First the Primacoustic, which rolls off most in the 250 hz range and slopes off from there. See below.
Primacoustic - Acoustical Solutions
The GIK monster trap seems better in the super low end, as its maximum absorption occurs around 80 hz, when mounted across a corner. See this page and scroll down.
GIK Acoustic Panels are tested and certified.
Let's look at Real Traps. Here is data for their Mondo Trap straddling a corner. The absorption peaks at around 140 hz, with a smaller peak at 80 hz.
RealTraps - Product Test Data
The point is that none of these really get down in the mud and nail that 40 -60 hz area. The GIK seems closest by taking a big chunk out at 80 hz, but still...
It drives me nuts that in an otherwise pretty good sounding room, when I walk into the middle of my control room a 40 hz test tone almost completely disappears.
And by the way Joshua (Kittonian), you should tell your friends at Primacoustic to try to maximize their website search data somehow. When I type Primacoustic into Google the first thing that pops up is Real Traps!
-R