Subwoofer Setup Guide
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 setup is crucial. This two-part guide will tell you everything you need to know about getting the most from your subwoofer.
Part I: Placement & Positioning
Part II: Connectivity & Fine-tuning
Subwoofer Setup Part I:
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.
REL's $798 T2 sub
(Credit: REL)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 theater 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 I've heard my share of "problem" rooms where the bass always sounds boomy/muddy.
In those cases try this method: move your couch or chair out of the way, or into another room, and start with the sub in the listening position. Yes, I 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' 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 I 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.
Subwoofer Setup Part II:
Connectivity & Fine-tuning
(Credit: Steve Guttenberg)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" hookup 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 labeled "LFE," "Direct," or "Bypass" (the red and black speaker level inputs and outputs' uses may be covered in a future blog).
To use the Sub/LFE input you'll need a long interconnect cable; most consumer electronics dealers stock these cables or try Radio Shack. 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 foot or two 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 setup menu, and on some receivers you'll be presented with a wide range of settings from 40 Hertz up to as high as 200 Hz. Your speaker and/or subwoofer's user manual may offer specific guidance in this area; otherwise use the Audiophiliac's crossover recommendations--for small speakers with 2 or 3 inch woofers, try between 150 and 200 Hz; for midsize speakers with 4 or 5 inch woofers, use 80 or 100 Hz; and with large bookshelf speakers or skinny floorstanding speakers, try a 60 or 80 Hz 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 center 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, center, 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 (such as Radio Shack's Model 33-4050) 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. I can set the sub's volume level with DVDs in 10 minutes or less, but with CDs I might be fiddling around days.
Auto setup A/V receivers can do a fine job with speakers, but most are less adept with subs. Actually most auto setup 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 setup to return to your original settings.
That's it for this how-to guide. Please send your subwoofer questions and queries my way via the comments section below.
Steve Guttenberg is a frequent contributor to magazines and Web sites including Home Entertainment, Playback, and Ultimate AV. He is a member of the CNET Blog Network, and is not an employee of CNET. Disclosure.
I brought the Elan sub based on your review in Home Theather Magazine, but it was a close decision between the Elan and the HSU in the above picture. The issue with the HSU is that it is shipped only and you can't find it in stores or boutiques so you can't see what it really looks like or listen to it with movies/music.
My sub was $429.00 & shipp. (PB10-ISD, now the PB10-NSD), and it does well - literally shaking the house.
When installing a sub merely to fill in the lower registers to support music playback ultimate bass extension is probably not all that important (anything around 30 Hz will be fine for 99% of music out there). In these cases corner placement is not only not necessary - it might work against you.
Generally - if we want to achieve a seemless ( or as seemless as possible) implementation between sub and speakers it is a good idea to place the sub so that it is approximately the same distance from the listening position as the main speakers are. If the sub can be placed between the 2 main speakers this works best.
Its also worth mentioning that most subs can support a speaker level connection running of the amp outputs and utilizing their own X-over. In these cases it is best to set the X-over at or around the point the main speakers start to roll off.
Subject to the relative speed of the sub Vs the woofers on the main speakers overlapping the bass may or may not work. In other words if my main speakers go down to 50 Hz and I set my sub X-over at 80 Hz the result might be dreadful (the sub is responding slower than the woofers to the bass gets muddy) or superb - in that the sub and woofers are at the same speed and the whole directionality of the bass is totally masked due to the overlap.
Overlapping the woofers does allow slightly more flexibility in placement in that you do not have the feeling the bass is coming from somewhere else other than the main speakers.
I have a sub woofer that went to a htib i tried to hook it up to my new reciver and it dose not work.
I called pioneer and they told me it need to be powered or buy a mono reciver. I looked in sup woofer'sand wow they are expensive, anyone one know where i could find one for short dough/ money
Crossover Freq. adjustments.
What do you recommend I do for proper setup and sound quality ? I want to use these along side Polk Audio RTA15TL's powered by separate Carver Amp and Pre-amp.
Thank you for your time and help concerning this matter.
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by bullseye279
March 5, 2009 1:12 PM PST
- I have a KEF Q-series powered subwoofer that all of a sudden, produces no sound. I checked the fuse, and it isn't blown, but it appears to be making a very dull, quiet crackling kind of sound. Is there a possibility my sub is blown? I never turn it up very loud, so this seems strange. Any advice would be helpful, as this was a very expensive sub, that can only be serviced in New Jersey.
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(12 Comments)Thank You,
Jason