Keep away from the walls, should not put loudspeaker at corners, space under stair ... because this is the position will create a bass enhance, causing deformed sound.

Clap hands for inspection of the room’s resonant level
The simplest way to check the level of sound-proof in listening room is to clap hands. If it is a long echo, it means the sound-proof is still not good.

Distance from listening position to two loudspeakers has to be equal
Please measure the distance from listening position to two loudspeakers again to achieve the stereo performance effect and the best stage’s space - should be equal. If you use carpet, you should use pen to mark listening position in order not to measure it again when we clean floor and carpet.

Do not put loudspeakers in parallel with the wall’s edge 
Although it was mentioned in the previous principle that we should set-up loudspeaker to listener’s position at an angle from 15 - 20 degrees, but some guideline books sold in the market still describe how loudspeaker arranged in parallel with the wall’s edge is. It is very easy to cause resonant room. Specialists when test technical specifications of the loudspeaker (frequency range, high sensitivity ...) always put loudspeaker at an angle of 15 degree into microphone. That is a reason why we must comply with this rule.

Reduce baritone of the loudspeaker with bass reflex design and the behind air-hole
For loudspeakers are designed bass reflex and the behind air-hole, if after implementation of those above principles on which bass is still not be balanced, you can use an old sheet of cloth or a foam mousse to insert into the holes. By doing this way, you will reduce the resonance of loudspeaker’s box from approximately 30 to 50 Hz.

Reduce glare at the high range
A small tip to reduce glared treble sounds is: Let try with a carpet.

Do not use the loudspeaker with bass reflex design in a small listening room.

According to these above principles, placement the loudspeaker with bass reflex design in a small room should be avoided. In a small room, due to the distance between front wall and behind wall is short, thus the resonant frequency will be easily same with the frequency of loudspeaker, especially bass reflex design. But if it is equipped with a double, you should use these above principles to reduce a resonance.

Note a height of treble loudspeaker and listener’ ears.
When you set-up, you should note that the height of treble loudspeaker must be in line with a height of listener’ ears at listening position. This increases the performance space and the opening of the theater.

(According to Audio-Visual)