Here is a well written article found on Avid’s monitor page on the subject of monitor placement.

“Why would anyone need directions for setting up reference monitors? Just put them on your desk, and you’re done, right? Well, it turns out that reference monitors are actually one of the most important and influential elements of your studio, and can really make or break the performance of your whole setup. It’s not that you have to spend a lot of money on them—with a good knowledge of monitoring fundamentals and a little bit of experimentation, you can put together an accurate system on any budget.

It can be extremely frustrating to spend hours slaving over the perfect mix—only to find that it sounds horrible in your car, living room, or another studio. A good monitoring system can prevent this by helping you to produce mixes that are clear, balanced, and translate well across a broad range of speaker systems. We’re going to delve into the most important points you need to consider when choosing and setting up monitors for your studio. This information will assist you in making educated buying decisions and, most importantly, help you achieve a professional reference standard that will further your artistic endeavors.

Things to look for

Whether you are recording, mixing, or mastering, your monitors are your primary and most important point of reference. Good studio monitors should let you hear exactly what’s been recorded. In other words, monitors need to demonstrate a relatively flat frequency curve, instead of boosting certain frequencies to make music sound more pleasing to the ear. They should also be rugged enough to withstand the demands of the project studio—providing an accurate, uncolored response at a wide range of volume levels.

Choosing the right reference monitors largely depends on how you plan to use them. Singer/songwriters may be fine with a compact set of 5” monitors, while urban/hip-hop producers will likely choose a larger monitor plus a subwoofer to achieve greater bass response. Most studio owners need a stereo configuration, but a surround sound setup may be necessary if you produce sound for TV, film or games. Since the monitoring system plays such a crucial role in the studio, it’s important to get high-quality monitors that fit your needs. It’s always better to visit your local dealer and listen to a few different models before deciding.

When test-driving studio monitors, listen to a recording that you’re familiar with, and ask yourself:

  • Does the bass sound tight and controlled, or uneven and muddy?
  • Does the stereo field sound sufficiently wide, allowing you to hear the separation between instruments?
  • Are the high-end frequencies smooth and crisp, or harsh and fatiguing?
  • Do I hear details in the mix that I’ve never heard before?

Using a Subwoofer

As a growing number of subwoofers are used in car stereos, home theaters and desktop audio systems, it’s vital that you hear the ultra-low bass frequencies in your tracks. Adding a subwoofer to your system can make a big difference in bass output. By carefully tuning the sub with the stereo mix, the low end is naturally extended in a way that fills out the sound, without adding a boom or unnatural low end. When properly integrated, a subwoofer can improve your overall monitoring experience by translating the extreme low end of the frequency spectrum.

Tip: Some subwoofers—such as the M-Audio SBX10—include a footswitch for bypassing sub output. This makes it easy to judge how the mix will sound on systems with and without a subwoofer.

The “location, location, location” cliché doesn’t just apply to the real estate market. It’s equally (if not more) applicable to the subject of loudspeakers and room acoustics. Strategic monitor placement is one of the most important factors in getting your sound right—and it’s simpler than you might think. Proper placement means choosing the best possible arrangement for your desk, speakers, and other studio equipment.

When it comes to monitor placement, you’ve probably heard a lot of talk about the “sweet spot.” This refers to sitting in the middle position between the two speakers, where the stereo image is optimized. The sweet spot lets you hear a true representation of the music so you can make accurate judgments while recording and mixing. When positioning your monitors, observe the following guidelines to maximize the sweet spot and enjoy better performance from your monitoring setup.

Align your speakers in an equilateral triangle from the listening position

When mixing, it’s important to sit as closely as possible to the center of the sweet spot. Select a comfortable seating position and angle each monitor to accurately face that position. The “toe-in” angle of each speaker should be carefully arranged at an equilateral triangle to the listener.

Place monitors symmetrically within the room

Try to achieve symmetry in the room when setting up monitors. For example, if the left speaker is three feet from the back wall and four feet from the side wall, place the right speaker the same way (if possible) in order to give each speaker a similar acoustic environment. By centering the listening position along a wall, your system will maintain better low-frequency clarity. In a rectangular room, the best sound can be obtained by orienting the console and loudspeakers into the room’s long dimension. This gives the low-frequency waves enough time to develop before hitting the rear wall (see figure 1).

Distance from back wall should be different than distance from side wall

It’s always better to place the monitor a different distance from the back wall than from the side wall. In other words, if your monitors are two feet from the back wall, make sure they’re not also two feet from the side walls.

When positioning your monitors, observe the following guidelines to maximize the sweet spot and enjoy better performance from your monitoring setup.

Place monitors vertically (or “right-side” up)

Although it may be tempting to place your monitors on their sides, this can significantly degrade the stereo image. Place the monitors vertically to get the best stereo representation (see figure 2).

Use monitor stands whenever possible

When you place speakers on a mixing console or desk, sound waves bounce off the flat surface before reaching your ears—degrading the tonal balance, clarity and image localization. Placing monitors on stands will prevent early reflections from interfering with your mix. (However, if this isn’t practical, it’s generally acceptable to carefully position your speakers on the desk or mixing surface.)

Tweeters should be at ear level

It’s important to place the monitors so the tweeters are at the same height as your ears (see figure 2).

Avoid placing monitors in corners

This helps prevent bass buildups that occur naturally at boundary and corner locations.

Place monitors at least 8-12” from the wall

This prevents sound waves from bouncing off the wall and reflecting back towards you (see figure 3). When using monitors that contain bass reflex ports, make sure there is enough space to prevent air flow obstructions. ”