I will make the assumption that you have a surround sound or home theater receiver and start from there. There are 3 main home theater speaker setups which you will see termed 5.1, 6.1, and 7.1 channel surround. You will also see mentioned the terms Dolby Digital, DTS, and Dolby Pro Logic. Let's dispense with the latter first: if your receiver is only Pro Logic (only older receivers at this point) you do not need to worry about 6.1 or 7.1 surround. There are some other formats such as Dolby Digital EX, Dolby Pro-logic IIx, Dolby TrueHD, DTS neo:6.1, DTS-ES, True-Surround XT, and undoubtedly more.
The two factors to consider are:
1. how many channels does your system permit, and
2. Do you want to buy that many speakers?
All the receivers that support more than 5.1 channels will also work fine with a 5.1 channel setup. Obviously, 7.1 will provide better surround sound than 5.1, but at the expense of two extra speakers. If you have a limited budget you will have to decide whether to buy 5.1 higher quality speakers, or go for cheaper speakers to allow for 7.1 channels. By the way, the .1 channel is the home theater sub-woofer. The sub-woofer is, in my opinion, really needed for home theater. A system will work without it, but I don't recommend going without for home theater. The center channel is also very important for home theater, serving to anchor the sound to the video screen. If you go to our site by the link at the bottom of this article you can see images for the descriptions following. These are the recommended placements according to Dolby Labs.
5.1 surround system:
A). Center speaker centered on video source
B). Sub-woofer(s) in arc with the main L & R speakers between speakers and video source
C). L & R front on a 22-30 degree angle from the sitting, on an equidistant arc connecting the center channel and subs
D). L & R surround equidistant and on a 90-110 degree angle from the sitting position
6.1 surround system:
A). Center speaker centered on video source
B). Sub-woofer(s) in arc with the main L & R speakers between speakers and video source
C). L & R front on a 22-30 degree angle from the sitting, on an equidistant arc connecting the center channel and subs
D). L & R surround equidistant and on a 90-110 degree angle from the sitting position
E). Rear center 180 degrees (directly behind) the sitting position
7.1 surround system:
A). Center speaker centered on video source
B). Sub-woofer(s) in arc with the main L & R speakers between speakers and video source
C). L & R front on a 22-30 degree angle from the sitting, on an equidistant arc connecting the center channel and subs
D). L & R surround equidistant and on a 90-110 degree angle from the sitting position
E). L & R rear equidistant and on a 135-150 degree angle from the listening position.
Sub-woofer Setup
Your sub-woofer may have a switch for Dolby Digital / Pro Logic. If you have a Dolby Digital capable receiver set it to that even if you are using Pro Logic. The same goes if you have multiple inputs on your sub. If your input is labeled LFE it is the equivalent of a Dolby Digital input. You want to use the input to the RCA style plug (or plugs) if you are using the sub-woofer in a surround system.
If you have speaker level binding post inputs, these are almost always for using the sub-woofer in a non surround sound speaker setup. Preset the sub-woofer level control to about halfway before running the white noise test tone to calibrate your receiver speaker levels. You absolutely must run the test and balance your speaker levels to have the surround system perform properly.
Don't worry about the crossover frequency control on the sub for Dolby Digital or better systems. For Pro Logic set it to the point where bass in your main speakers drops off, which will require looking at the documentation for your speakers.
If you are not using your sub in a surround system, you may, with advantage, use the speaker level inputs on the back of your sub. The advantage to this is if you have small speakers. The receiver left and right channels are connected directly to the sub-woofer, and the left and right speakers connect to the speaker out connectors on the sub-woofer. What this does is allow the sub to produce the low bass that the main speakers can not, which of course the other types of connections would do also. The advantage here is the fact that with the sub-woofer connected this way, it filters the bass out of the signal, so your main speakers never try to produce the bass that they can't handle. This results in clearer, cleaner sound and more volume capability from your main speakers.
Sub-woofer placement is generally as below for other speakers. It is true that bass is omnidirectional and so you should be able to place a sub-woofer anywhere, but as usual this depends on your situation. I play music loud, and can detect where the sub-woofer is located by the feel of the vibrations. I find it very distracting to have the bass seem to come from the front of the room, but the vibrations of the bass coming from another direction. I therefore always prefer a sub-woofer to the front of the room.
How to get the most out of your speakers (How to improve your sound quality for no extra money )
The first consideration with a new speaker system is placement, and the second is wiring, both of which deserve consideration. We will cover wiring first with some generalities that apply to all kinds of speakers. The placement part will cover in home speakers only.
Wiring your speakers
First and foremost, wire selection can be very important. If your speakers are to be installed in-wall, you will need speaker cable rated cl3 or equivalent. If outdoor speakers, you should try to use what is termed direct burial cable or equivalent. Next, if you care about the sound quality at all, 22 gauge cable is not recommended. It can be used for very short runs, and is smaller for hiding, but due to resistance you will sacrifice some sound quality. I would recommend 16 gauge wire for most runs, unless you really want to get the best out of your speakers, in which case use 12 gauge or larger. For a long run I would recommend larger than 16 gauge. (We have a cable article and distance chart on our site at the link at the bottom.) I personally use a good audio quality 12 gauge cable myself, but you will pay more for cable this large. The advantages are better dynamics, and the amplifier can control your speakers better due to low resistance wire. As always, let the price point of your speakers determine the cable. Don't put expensive cables on cheap speakers, and vice versa. BTW, don't try to use romex (house wiring) instead of decent quality audio cable. Really, just say no. For so many reasons.
One common question is if fancy cable makes any difference. I must state here that many persons consider the very subject to be so much snake-oil. I personally believe that I can hear some differences, depending on the quality of the associated system. In other words, any hearable differences in cable will be more noticeable in a system with more resolution. Also consider that many listeners not selling cable claim to hear a difference. Consider any double blind tests carefully. I usually can pick holes in the logic behind most of these tests, and point out factors not considered. One perfect example was an amplifier test (by a major audio magazine) that level matched the amps, did a double blind test, and asserted the amps sounded identical, so they recommended that everyone buy the cheaper amp.
Here's the rub: Under their exact conditions, which are not normal listening conditions, the amps sounded the same. Consider this unmentioned idea: The cheaper amp had less power output than the other, and under normal listening conditions, say with loud rock music, and inefficient or difficult to drive speakers would have pooped out before reaching satisfying listening levels, not to mention clipping and distorting from over-driving the amp. One problem with the double blind tests is, in order to be accurate, they have to control every factor in the universe that could affect the results, even unknown factors. The other is, in order to compare everything on an even playing field, they purposely diminish or nullify the differences, then triumphantly proclaim they are all the same. The perfect example from above is level matching at a volume level that does not stress the more easily stressed amp.
Polarity or Phasing of your speakers is very important. This means finding the wire with a stripe or writing on one side, and connecting that wire to either the + (red) or -(black) on the amplifier and the speaker. It does not matter whether the stripe on the wire connects to plus or minus, as long as it is the same at both ends, and on all speakers. I always connect the plus to the stripe, just to be consistent. If you get this wrong you will lose almost all your bass response, and voices will float around instead of being centered when they should be.
Home Speaker Placement
Ideal placement for best sound is going to vary with the type of speakers you have, but we can supply some good generalities. Obviously, for a surround system, you have some built in limitations. The center channel needs to go above or below center of your television, (or perhaps centered behind a projection screen) and the left and right front need to go to the left and right front. So on for the rest of the speakers. It should be added at this point that for surround sound placement the ideal is all 3 front speakers an equal distance from the listener. This actually places the front speakers on an arc. It is generally good to put rear surrounds a little higher than ear level so that all listeners get a better chance to hear all the speakers. Leaving aside the obvious details of surround sound, here is how to improve the sound of your system for free.
First, don't put anything in front of your speakers, and if they are placed in a cabinet make sure that the front of the speaker is even with the front of the cabinet. Also, keep in mind that some speakers such as the rear ported variety perform very poorly in cabinets. Make sure speaker ports, which may be in the front, rear, side or elsewhere, are not blocked. This goes for sub-woofers also. Stability is also important, your speakers need to remain stable at high volume levels. If they move with loud drum beats, your system will be robbed of punch and impact. If you use speaker stands make sure they are stable enough for the size of speakers you have. One quick tip is to use some blu-tack or mortite putty between the speaker and stand to improve the coupling and add stability. Spikes on the bottoms of the stands work well for carpeted rooms.
Next, check out the sound of your speakers. Many speakers sound better when aimed directly at the listener, and located at ear height. This is not always the case, however. If the treble or voices sound a little too sharp, then perhaps the speakers will sound better aimed straight out instead of at the listener. Listen to the bass. Is it boomy, or lacking? If your speakers sound a little boomy, like they are in a barrel, bass response can probably be improved by moving your speakers farther from a wall or corner. If your speakers are too light in bass, they may sound better closer to a wall. Remember not to block any bass ports. If the speaker is rear ported it needs a little space out from the wall and clearance on the sides of the speaker to perform properly. One little tweak you might try: some speakers sound better with the speaker grills off. Try removing them and see if they sound better. In many cases there will be no noticeable difference, but it costs nothing to try.
Other issues: If your speakers are correctly phased as described above but voices are not sharply locked in location you may have your speakers too far apart. This generally applies to stereo, not surround sound. If not used on a surround system, the sub-woofer crossover point should be adjusted to coincide with the drop off in bass from your main speakers. You may find this listed in your documentation, usually on the order of the -3db point. If after all this your speakers don't seem to perform like they should, you should consider whether the amplifier attached to them is up to the task of driving them. There are more issues here than power, especially impedance. An amplifier that has high wattage may drive 8 ohm speakers well, and do very poorly on 4 ohm speakers if the amplifier is not designed for "high current" or rated into 4 ohm speakers. In addition, many amplifier (or receiver, home theater amplifier, etc) manufacturers use various methods to exaggerate the wattage ratings on their amplifiers. The true rating to look for is called the RMS rating, and should be rated into a specific impedance (4 ohm, 8 ohm) etc and at a specific distortion rating.
