Merely buying a great subwoofer is no guarantee you'll wind up with great bass. There are too many ways to squander its performance potential, that's why putting in the extra effort to achieve proper subwoofer set-up is crucial. This guide will tell you everything you need to know about getting the most from your subwoofer once you bring it home.
Placement & positioning
While your subwoofer's deep bass is non-directional, you can't just stick the sub pretty much anywhere that's convenient without possibly forfeiting most of the quality you paid for.
Finding the right spot in your room can make a dramatic difference in the way your sub sounds. Corner placement is the de facto strategy for most people, possibly because it's out of the way and almost always produces the most bass, but corner placement may not yield the most accurate bass (and/or smoothest transition to the satellite speakers).
With small (8-inch tall or less) speakers it's best to keep the sub within three or four feet of the front left or right speakers. Once the sub is a lot further away it's just that much harder to maintain the illusion the bass is coming from the speakers and not the sub. And that goes double for small home-theatre-in-a-box-subwoofers; keep them as close as possible to the front speakers. Oh, and don't be shy about volume when you're finding the right spot for the sub, turn it up so it's easier to hear what's going on down there.
Some placement experimentation may be useful here, play a CD with lots of deep bass and keep repeating the track as you move the sub to all of the visually acceptable locations in your listening room. You'll be amazed just how different the bass will sound in different locations — some will be muddy, some will sound louder and some will reduce the bass volume. The goal is to get the best balance of deep bass and still have mid and upper bass in equal proportions. In some rooms that's not all that hard to achieve, but we've heard our share of "problem" rooms where the bass always sounds boomy/muddy.
In those cases try this method: move your sofa or chair out of the way or into another room, and start with the sub in the listening position. Yes, we know that sounds like a crazy idea, but it's just for test purposes. Now play music and movies with lots of bass, and take a little stroll around your room, stopping in the spots where you'd like to place the sub. As you move about you'll notice the bass's apparent loudness and definition changes from place to place.
When all else fails, try locating the sub as close as possible to your couch or chair, in what we call the "end table" position. That location can work wonders.
Larger speakers are generally easier to match with subs and small speakers and/or speakers with 4-inch or smaller woofers can require more fine-tuning to get right.
Connectivity & fine-tuning
The Hsu Research subwoofer's rear panel pictured on the right is fairly typical. To non-audiophiles the maze of connectors can be intimidating, but in most instances the single cable "Sub In" hook-up is the easiest and best sounding method. You can see the Sub In here on the Hsu's rear panel; on other subs the input may be labelled "LFE", "Direct", or "Bypass".
To use the Sub/LFE input you'll need a long interconnect cable; most consumer electronics dealers stock these cables or try Dick Smith. How long is long enough? Measure the distance between your A/V receiver and sub and remember to include the distances up and down over doorways and furniture. Buying a cable that's a metre too short is a drag, and after you've opened the package you may not be able to return it for a refund or exchange.
Next, turn the sub's frequency/low pass crossover control knob to its maximum, highest numerical setting (you're going to rely on your A/V receiver's internal crossover control to route the mid and high frequencies to the speakers and the bass to the sub).
You'll find the receiver's crossover setting in the speaker set-up menu, and on some receivers you'll be presented with a wide range of settings from 40-Hertz up to as high as 200Hz. Your speaker and/or subwoofer's user manual may offer specific guidance in this area; otherwise use our crossover recommendations — for small speakers with 2- or 3-inch woofers, try between 150Hz and 200Hz; for mid-size speakers with 4- or 5-inch woofers, use 80Hz or 100Hz; and with large bookshelf speakers or skinny floorstanding speakers, try a 60Hz or 80Hz crossover.
If you're lucky enough to have large floorstanding speakers with 8-inch or larger woofers, you may wish to run them as "Large" speakers, without any crossover. But your centre and surround speakers will still likely work best run as "Small" speakers, and benefit from the crossover settings referred to in the previous paragraph.
One of the other subwoofer controls is marked "phase". It's provided because the speakers and the subwoofer sound best when they are "in-phase" — meaning their woofers move in and out in synch with each other. To check if your sub's phase is correct, play music with lots of bass, listen for a minute or so, and have a friend sitting by the sub flip the sub's 0/180° phase switch slowly back and forth. The "correct" setting is the one that yields more bass. You may have to try a few different recordings before you hear any difference, and it might help to turn up the sub's volume level a bit for this test. If you don't hear any difference between the "0"- and "180"-degree settings, just leave the phase control in the "0" position.
Setting subwoofer volume is next. Precisely matching the volume levels of the left, centre, right, and surround speakers is important, but bass volume is more subjective. Some folks like to feel the sub working the room all the time — and some prefer to only hear the sub's contributions with big special effects driven movies or dance music. A Sound Level Meter can be a big help when setting speaker level, but it's nearly useless for determining the sub's correct volume level. The "by ear" method works best.
DVDs' bass tends to be fairly consistent from one disc to the next, but CDs' bass will vary a lot more. Adjust the volume (on the subwoofer itself or the receiver, whichever is easier) as you play through a stack of discs. We can usually set the sub's volume level with DVDs in 10 minutes or less, but with CDs we might be fiddling around for days.
Auto set-up A/V receivers can do a fine job with speakers, but most are less adept with subs. Actually most auto set-up receivers do a lousy job with subs. Try readjusting the receiver's crossover setting, check phase and volume level. If you don't like the change, rerun the auto set-up to return to your original settings.