The importance of home theater calibration preview

Very good to post in India first AV forum and good to see people like nishant in these forums as well.

The importance of accurate home theater calibration cannot be over stressed. If you want to get the best from your system you need to ensure that it plays your source material as transparently as possible. While some people prefer colored or distorted sound in some cases, the accurate delivery of sound by a system is very important to achieve a complete listening experience.

I will be posting a series of small articles based on what i learnt by interacting with various sound design and acoustic experts in the film and music fields and also my own experience in setting up and calibrating my modest home theater.

Stay tuned ...

Lakshman

Many people give importance in home theater systems to the video and the display aspect more than the audio aspect, but as George Lucas the creator of stars wars series often quoted sound is 50% of the movie experience.

Why do we need home theater audio calibration in the first place?

The movie industry started with sound in 1927 with jazz singer made by warner brothers, since then constant improvements have been made to sound technology. One problem which early sound recordists faced was with the varying quality of playback equipment in theaters which caused problems when movies were played. Some halls sounded great some were bad. The Hollywood industry came up with the Academy standard which specified the type of speakers and the way in which sound should be recorded so that it replayed back in the theater with a good amount of accuracy.

In the 1950's various studios tried various 70mm sound formats like cinerama and others. But it was in the year 1976 that the movie sound scene was changed forever. A smart chap called Ray dolby who had a strong physics background, devised a method to reduce noise levels in film sound tracks and increase the quality. To develop his system a series of standards came into place which are used even today. In 1991 dolby digital 5.1 surround was introduced with 5 main channels and .1 being a bass channel. It became essential to have a highly calibrated system in place for recording and reproducing these very high quality sound tracks. These standards found their way into the home theater arena as well.

Below are some of the important calibration aspects in a home theater setup which i will list down and explain in detail as we go along

Speaker levels -Technically as per the standards given by dolby, at one fixed master volume each speaker should play a test tone at 85 db level when measured with a sound level meter.

Speaker distance-This specifies how far the listener is from the speaker, a delay is added to compensate for the difference in arrival of sound waves from various speakers.

Speaker Cross over- An important part of setting up a home theater or movie theater system is setting the frequency up to which you sub woofer would work and then sound above those frequencies would get transferred to the main speakers.

We will deal with each of these in detail in the next articles