The importance of home theater calibration part02

I hope you enjoyed part 01, in part 02 we will learn about home theater and speaker calibration.

Before going into the topic it is essential that for reproducing music in stereo or Movies in multichannel you need to have timbre or tone matched speakers. Sticking to one brand of speakers made by a manufacturer is a good idea as you get various 5.1 matched speaker packages nowadays. This ensures a even sound field and smooth 360 degree panning.

The main speakers in a home theater system are

Left and Right- (Also used for stereo listening) These carry almost all the Music and Foley effects in a film, they are used to anchor the sound in the front sound stage.

Center-THE MOST CRITICAL speaker in a home theater. Needed to reproduce all the dialogue and most of the effects which move from front to surround. Select a speaker which sounds very natural with the human voice.

Surround Left and Right- In 5.1 systems these are used to convey various atmosphere effects like rain or other subtle effects. They should never be noticed during playback until a effect is placed into them by the sound mixer like a space ship passing from front to surround. In 7.1 systems there is a surround back left and surround back right which are placed between the left and right surround speakers.

Sub woofer-This is used to reproduce the bass in the recording, LFE is is not the output to the sub woofer, it is separate thing which i will discuss later.

It is critical to place the speakers of the L and R channels in line with the center as far as possible. The L and R should be placed at a 45 Degree angle to your listening position. Center should be placed so that dialog matches the screen and is clear. Surround speakers should be placed at a 110 degree angle from the listening spot.

Sub woofer - It can be placed wherever it sounds clean and is not booming.

Now coming to levels setup. Dolby an DTS recommend that all the front speakers surrounds and sub be set to 85db of sound pressure level.

The problem in many home theaters is we never listen at full theater volume in a small home so achieving 85 db which is very loud for home standards is difficult. It is important to set the levels of all you speakers to read equally at least to ensure accurate playback of movie and audio material. Every home theater unit has pink noise or a button which says speaker test, pressing this creates a buzz sound like the sound between FM stations. Using a Sound meter which is set to C position weighted you must ensure all channels read at the same level. DO NOT CHANGE THE MASTER VOLUME of your receiver while doing this. Ensure each channel reads as close to the other and also set the sub woofer level which should read 4db higher or 89 db on the meter due to its measurement process. The level adjustment is done in the receiver which has a menu for changing the levels. Finally play a good DVD and feel the experience of being drawn in to the film. In 7.1 Systems the surround back left and surround back right should be set to 82 db respectively.

Next Article will deal with Cross over and receiver Settings.

Laksh

I can vouch for that!

Calibration is something that we all ignore or trust the auto calibration of the receiver. An entry level but well calibrated setup would sound better than the not so well calibrated setup with all the bells and whistles !!!

lakshmant,
the whole forum must be really greatful yo you for the informations u provide.for a person like me with less technical knowledge & more enthusiasm, this is so worthy
thank you very much,
dennis

Hi,

Where do you get a sound level meter in Bangalore? How much does it cost?

Thanks,
SilentSound.

1. Bosstek Make Analog Sound Level Meter Model 33-2050 - @Rs 1950/-each+4% tax.
Seven sound level ranges - 50 dB to 126 dB
A & C weightings - lets u check compliance with safety regulations as well as make acoustic analysis
Bulit in Battery condition indicator
Phono type output jack - for connection to home theater to test equipment
Threaded insert - lets u attach the meter to a camera tripod for increased accuracy .

This is very similar and i think the same as the common radio shack meter. Also good dealer i sent him a cheque and got the meter in 2 days. Here is the address

Instruments & Machinery Sales Coprn
Fort, Mumbai -400001
Tel : 22691733 Fax : 22678864

Please mug this link... lot of info

Car Audio Installation and Home Audio Guide

Radioshack is (world popular) forum favourite, I've both analog & digital and found analog is more user friendly and readable while C weighing. Need to load correction values for better results.

But, if you are looking to calibrate the frequencies <20zh Galaxy 140, or similar is advisable


HTH