If you're like us, getting a new toy like the SUB 25 just demands some initial playing around. Before we started proper setup, we schlepped it in place next to our reference sub, set the level at about 1/3, plugged it in and ran some music as a "smoke test." The Paradigm logo on the front lit up very faintly in blue and we got way too much bass. After backing the SUB 25's level down, we broke out our SPL meter and jumped into some test tones.
This sub dives deep.
Deeper than we could hear, in fact. Even at low volumes, stuff on our walls was rattling, the pets were running for cover, and our SPL meter told us something was a-going on. So yeah, the SUB 25 does at least 17Hz, but we didn't hear it in our ears.
Having a subwoofer that is separate from your primary speakers is advantageous for two reasons, really. First, producing really deep bass requires either a lot of power or a lot of volume, neither of which you probably want to saddle your L/R speakers with. Second, being able to position your subwoofer independently from your mains allows you to optimize the bass response in your room. Especially at low frequencies, the room has a dramatic effect on sound quality -- ever notice how you hear more bass when you're standing next to a wall than in the middle of the room? Before setting loose any electronic/signal processing magic on your sub, it's best to try and simply find the best place to put it in your room. You can search the web for various subwoofer placement practices -- even if your choices for sub placement are limited, use one (we're partial to the "crawl for bass" approach).
Some people just have a knack for setting speakers up. For the rest of us, there's room analyzer software (we used Room EQ Wizard) to help. We spent a good amount of time listening to test tones and looking at the resulting graphs to dial in the SUB 25 level, phase and crossover controls, and ended up with a pretty smooth transition from our main speakers to the SUB 25. We should mention that we're not big fans of rear-panel controls, and the SUB 25's are no exception. Tuning the sub involves reaching behind, twiddling a knob, and then assessing the change. It's a minor gripe, especially since most users only do the setup once, but it's a lot of back and forth that's made worse by the fact that it's hard to see the knob settings since they're around back. Remote controllable knobs or a separate knob control panel (maybe even use that USB connection) would make setup so much easier. The Perfect Bass Kit
Paradigm was kind enough to send along the $300 Perfect Bass Kit (PBK-1). If you're going to cough up $4,000 for a SUB 25 and you don't have some other form of room correction in your system, we'd suggest you get with the times and pick up the $300 PBK-1 as well. It's unlikely that an AV enthusiast considering the SUB 25 won't have some room correction in their receiver/processor, but we suspect that dynamic shifts significantly when music-only shoppers get involved.
The PBK-1 includes a mic stand, calibrated USB microphone and software (Windows only) that borrows room correction technology
from Anthem, a sister company of Paradigm. Plug the SUB 25 into one USB port of your computer, the calibrated mic into another, and fire up the software. Then you can take from 5-10 sweep measurements from around the room and the calculated room corrections are sent to the SUB 25.
This approach is interesting for a few reasons. Because the SUB 25 only accepts an analog input signal, it must be digitized before the PBK-1's EQ/filtering can work its magic. The tin-foil hat crowd might not like the idea of one more analog to digital roundtrip, but we're just talking about the subwoofer signal, here. Another concern might be any additional delay induced by the roundtrip. Again, sub effects are much more forgiving of any delay than, say, the dialog channel, and Paradigm uses IIR (infinite impulse response) filters which have less latency than FIR (finite impulse response). Finally, the PBK-1 only deals with modifying the SUB 25's signal -- there's no highpass breakout on the SUB 25 to send filtered audio back to your main channels. In other words, the $300 PBK-1 won't give you the full-range room EQ that the Anthem Room Correction software in conjunction with a Anthem processor will.
Tin-foil hats notwithstanding, in the real world the PBK-1 delivered as promised. The measured responses that we got after the PBK-1 treatment were smoother than our manually-tuned results. Particularly, dips and peaks at around 30, 55 and 90Hz were much smoother. A narrow 90Hz crater that we have in our room was still present, but much better after using the PBK-1. Most importantly, things sounded slightly clearer after room correction with the PBK-1.