Well one of the problems with many people with subwoofers
they want to be able to point at it and say, "There's my subwoofer."
A good subwoofer placement though should be about disappearing, integrating with your music
so your speakers, your stereo image, becomes a complete picture.
Step 1: Initial Placement
Set the subwoofer at an odd numbered partition,
such as 1/3 or 1/5 of the length of the wall opposite the main listening position
and opposite major openings like doors and windows.
Step 2: Choose your connection
Connect your processor or receiver to your subwoofer.
Keep your cables loose because you're going to me moving your subwoofer around.
There are three main connection possibilities.
The LFE signal, the two channel, or left and right line inputs, or both.
LFE is a bit confusing to may people because they tend to use it
as their primary connection for most subwoofer setups.
LFE stands for "Low Frequency Effects" channel.
It is an independently recorded effects channel that movie producers
will use to enhance dynamics, explosions and other special effects.
In music, there's no such channel.
By using the pre-amp right/left outputs of your processor
you'll be able to pass that bass information that's naturally in your stereo channels
to your subwoofers and enhancing the full-range response of your speakers.
If you are using an LFE connection in your home theater system
there's an easy sound check to determine if your processor is sending a signal for 2-channel use.
Simply play a two channel recording and listen to see if any sound comes from the subwoofer.
If the subwoofer does make sound, you don't have to connect the left and right line inputs,
and can ignore any section in this video marked for 2-channel setup only.
If there isn't bass coming from your subwoofer while the 2-channel recording is playing
then you either need to change the settings on your processor,
you'll want to look at your processor's manual for that,
or you'll need to connect the left and right line inputs and follow all setup steps in this video
for LFE, 2-channel, and both.
If you're using the speakers only as part of a 2-channel setup, and not as part of a surround sound system,
you can connect using the left and right line inputs,
and ignore any steps in this video marked for LFE only.
Step 3: Initial Settings
Set your controls to their initial settings.
Your level should be set to 4.
Phase set to 90.
Set the low pass filter to 70% of your main speaker's low frequency extension.
For example, if your front speakers are rated down to 50 Hz
set it to 35 Hz.
If your subwoofer has a level adjustment knob
it will have values like 25 Hz or 50 Hz, or some other adjustment.
Set these to zero.
Step 4: Final Placement
You're going to set the subwoofer to where you normally would be listening.
Then playback a recording.
Crawl around and listen to the bass response in different places where you'll put the subwoofer.
You can close the blinds if you're worried about what the neighbors will think.
Well often, as you're crawling around the room
you may find places where the subwoofer seems almost out of control
as if you've turned up the volume dramatically.
Some ratios of length, width or height in your room, happens to be complementary
and you end up with a large peak at one very specific frequency.
The result is, you'll only have that one note play well.
All the other notes tend to suffer.
So what you want to do is to listen for multiple bass frequencies, get all the notes right.
Once you find that sweet spot, move the subwoofer to that spot.
Take a listen from the main listening position to double check.
Step 5: Fine Tuning
You'll tweak the controls to fine tune your subwoofer's integration.
For steps involving the left and right line inputs
you'll want to listen to a 2-channel recording.
For steps involving the LFE only, you'll want to listen to a familiar DVD or Blu-Ray.
If you have the left and right line inputs connected, you'll set the lowpass filter first.
While you listen, have a trusty assistant start turning the lowpass knob up
until the sound start pulling into the subwoofer.
Then back it off to the proper setting.
Now, for speakers connected to an LFE signal, you're going to set the control in your processor.
Consult your processor's manual regarding how to access these setting for your particular processor.
If you have both LFE and left and right line inputs connected
set your system to LARGE for your mains
then BOTH or subwoofer mode, sometime also called ULTRA.
This will allow 2-channel bass to go out to the right/left connections,
and LFE out to the LFE output.
If you're using smaller speakers that can't handle much bass below 80 Hz,
then set them for SMALL
LFE with be the only cable needed,
but you'll need to compromise on bass levels for music and movies.
For all LFE setups, start at these settings.
Crossover: 70 Hz
High Pass: 12 dB
Low Pass: 24 dB
If you're using a wireless subwoofer, add 14 ft to the sub distance settings to adjust for latency.
From these points adjust these settings while listening to a familiar DVD or Blu-Ray
so the bass sounds like it's coming from the speakers, and not the subwoofer.
Now for all setups, you'll adjust the phase.
Play a 2-channel recording with a lot of bass and rock the phase control between 0 and 90 degrees.
Listen for how the notes start and stop, relative to the main speakers.
Listen to that male singer, if his body doesn't seem to focus as an image
it can mean the subwoofer may be out of phase relative to your main speakers.
Chose the setting with the least amount of drop in bass response.
If you prefer zero, switch between 0 and 270 degrees.
If you chose 90, switch between 90 and 180 degrees.
Chose the settings that achieves the best blending between the speakers and the subwoofer.
If your subwoofer has a level adjustment knob labeled 25 Hz or 50 Hz
use the same recording and put the knob down to -10 dB and listen.
Then go up to +10 dB and listen.
Keep moving between low and high extremes, closer and closer to zero
stoping to listen at each point.
Pick your favorite and leave the control on that.
Finally, you're going to set the level for your subwoofer.
With the 2-channel recording still playing,
increase the level control until you can hear the bass coming from the subwoofer itself,
rather than it sounding like it's coming from the main speakers.
Then, back it off just enough so that the bass sounds like it's coming from the main speakers.
A good analogy for what we're trying to accomplish here is similar to what you do
when you're focusing a good SLR camera.
You'll take your focus ring out to the point where the person looks diffused, soft.
Then back it up slightly until it snaps into sharp focus.
Essentially that the same thing you're doing with the controls on your subwoofer
and the setup regime we've discussed.
If you're using the LFE connection, you'll want to set the level in your processor as well.
Leave the level control on the subwoofer itself the same,
and adjust the level in the processor in a similar way.
Now, you may set the LFE output a bit higher for more dramatic movie playback.
That's it! Enjoy richer bass and enhanced home theater audio.
The total goal of what you're going through with all these steps
is to essentially blend the subwoofer, make it seems as a complete package,
spend some time, and you'll find that once it's integrated you'll have a much fuller range
with much greater sense of dramatic impact for both music and movies.