It’s the time of year for saving money!
I’m a big fan of subwoofers. Whether it’s a surround or
stereo, subwoofers will get you the bottom two octaves of the music far more
cost-effectively and in a room-friendly way better than any “full-range” speaker I’ve ever
seen.
All my room-based systems use stereo right/left subwoofers. I’ll
put my pair of JL Audio F-112 subwoofers up against any single sub, regardless
of size of price. I even use stereo subs with my Dunlavy SC-VI speakers, which each
sport a pair of 15″ drivers.
The reason I use stereo subs is simple – they deliver more
convincing and directional bass. But bass isn’t directional below 80 Hz (the
THX standard crossover point). True, but since most subwoofers use a gradual
roll-off, be it 12, 18, or 24 dB per octave, it means that a subwoofer still
puts out some directional information.
Even two octaves up from 80 Hz with a 24 dB crossover slope (320
Hz) a subwoofer still has some midrange output. Sure it’s not much level (being
48 dB down), but it is enough to be audible in some setups and with some
sources. The leading edge of bass transient is the primary problem. This
leading edge contains upper harmonics that are will into the midrange. Mono
subs can “pull” a low frequency instrument’s image towards the center of the
soundstage because its leading edge is coming from a more centralized location
than it should because of the subwoofer. Stereo subs eliminate this problem.
Stereo subwoofers also “share the love” so that each one
only has to work half as hard to produce a given output level. Personally I’d
rather have two moderately priced subwoofers in a system than one that costs
three times as much. Not only will the two have lower distortion at higher SPLS
because each one will be operating in a more linear fashion, but with two subs
you can reduce room resonance peaks and place them in locations with less room
gain because you won’t need as much room gain. And although room gain is a
cheap way to get more output from a subwoofer, it is not without sonic
trade-offs. The principal trade-off is that room gain is not linear – it
amplifies only those frequencies that engage a room’s resonance nodes. The
result is often “lumpy bass” which while impressive, is not correct.
So the next time you begin to lust for those big full-range
speakers in your dealer’s showroom, perhaps trying a couple subwoofers with
more modestly sized speakers might be a more cost-effective way to get better
sound.
I feel like the myth went from “it’s fine you can put it anywhere, hide it in the corner under the table, it’s omnidirectional” which sorry just is not true. Anyone can stand on front of their subwoofer and hear / feel it. It’s a multi sensory experience.. Movie theaters typically have a sub at each side. Even adding a an subwoofer behind you in a surround setup crossed over with your rear / surrounds will balance out the stomping of explosions as you turn around in video games etc.
Once you get two subs and switch to stereo bass there’s just no denying that there is an obvious difference. I hear a lot of people speak or the reductions of nulls or a bump in spl but that’s never been an issue from your main listening position.
The gains you get from stereo bass albeit sure there are a lot of songs that sum the bass instruments below 40hz or so, but that still doesn’t account for all the other sounds that happen to filter through the subs and the phase preservation creates an obvious sense of expanded low end whether it’s a dragon swooping, an organ or bass guitar. This is especially true in live recordings where the band is recorded so that when played back you hear the entire room, from the spacious ambience of the echos to the interwoven bass textures that would only be possible with stereo subs.
I wonder if maybe most people who argue otherwise have full size tower speakers that play reasonably well down to 40hz already thus already behaving as if they were subwoofers.
While your response is to a ten-year old blog, I agree with you, even ten years later, two subs are far better than one…