It just so happens that the April issue of Home Theater compares the $799 Def Tech Supercube 4000, the $1799 REL R328, and the $6300 JL F212. In another review they cover a system from Emotiva, which includes their $499 X-Ref 10 sub.
I was surprised by this fairly expensive REL's frequency response. It was a simple resonant spike that centered at 45 Hz and dropped off rapidly above and below that. It was down about 12 dB from that spike at 30 Hz and 100 Hz. You may get a good blend with the right speaker and good extension with boundary reinforcement, but it doesn't give you much bandwidth to work with. Home Theater worked its way around this by calling the 45 Hz frequency a +6.5 dB peak, while the -3dB point was 30 Hz and 103 Hz. But they also said that the 6.5dB peak would normally disqualify it from recommendation except that REL states that their subs are designed to rely on room reinforcement for more linear response. I say it makes it a fussier sub to position and integrate.
However, this is just one of REL's many sub models. Others may have broader response curves.
By contrast, the $1K cheaper Def Tech Supercube 400 had a flatter curve anchored by two resonant peaks at 30 Hz and 60 Hz. At the low end it was down 10 db at around 25 Hz and 100 hz. The dip between the resonant peaks at 30 and 60 Hz was a mild 2-3 dB. Using the same curve interpretation used on the REL, the Def Tech's -3dB points were 26 Hz and 94 Hz, still better than the REL. And for the difference in price you could buy two and still save money.
The JL F212 had the kind of response curve we think (or hope) we're getting but seldom do, with a nearly flat curve (-3dB at 20 and 100 Hz) from 20 to 100 Hz and a -10 dB drop at about 170 Hz.
Even the $499 Emotiva ha a flatter curve, with a -3dB point at 33 Hz, -6dB at 31 Hz, and an upper -3dB point at 117 Hz.
I was surprised by this fairly expensive REL's frequency response. It was a simple resonant spike that centered at 45 Hz and dropped off rapidly above and below that. It was down about 12 dB from that spike at 30 Hz and 100 Hz. You may get a good blend with the right speaker and good extension with boundary reinforcement, but it doesn't give you much bandwidth to work with. Home Theater worked its way around this by calling the 45 Hz frequency a +6.5 dB peak, while the -3dB point was 30 Hz and 103 Hz. But they also said that the 6.5dB peak would normally disqualify it from recommendation except that REL states that their subs are designed to rely on room reinforcement for more linear response. I say it makes it a fussier sub to position and integrate.
However, this is just one of REL's many sub models. Others may have broader response curves.
By contrast, the $1K cheaper Def Tech Supercube 400 had a flatter curve anchored by two resonant peaks at 30 Hz and 60 Hz. At the low end it was down 10 db at around 25 Hz and 100 hz. The dip between the resonant peaks at 30 and 60 Hz was a mild 2-3 dB. Using the same curve interpretation used on the REL, the Def Tech's -3dB points were 26 Hz and 94 Hz, still better than the REL. And for the difference in price you could buy two and still save money.
The JL F212 had the kind of response curve we think (or hope) we're getting but seldom do, with a nearly flat curve (-3dB at 20 and 100 Hz) from 20 to 100 Hz and a -10 dB drop at about 170 Hz.
Even the $499 Emotiva ha a flatter curve, with a -3dB point at 33 Hz, -6dB at 31 Hz, and an upper -3dB point at 117 Hz.