This highly depends on the home theatre amplifier you are using. Let's consider the problem in a general way. We have 5 or more speakers to tune, one with respect of each other.

There are three approaches you can consider:

• Calibrating by ear
• Calibrating using a decibel meter
• Calibrating using a spectrum analyzer

What we want to do first, is to eliminate as much variables as we can. To do that, we will consider our two main left / right speakers as the reference to which all other speakers will be calibrated.

If you can, disable all other speakers but the two main for now. Once you have done this, adjust the volume level so that you are at a comfortable earring level, but not too loud. Then, adjust balance so that the sound seems centered in the center of your screen (put the amplifier in mono mode to make this easier). Some amplifiers have an option to generate white noise tones. Turn that on so that it provides you with an easy to work with sound. Once the volume levels seem correct, you need to see if the equalization is correct. Here again, it will depend on if your amplifier allows you to set separate equalizer settings for each speakers or just groups of speakers (front vs rear vs center). Usually, you will not have much difference in equalization between the left and right main speakers. If you notice a difference, it may be caused by the presence of objects in the room that absorb sound waves from a speaker or both. The room shape may also create this sort of problems. Your two main speakers should sound exactly the same on the full range of frequencies they can emit from your center seating position.

Once the main speakers are calibrated, we will repeat the equalization process for the center speaker. First adjust the center speaker gain so that it sounds no louder or fainter than the two main speakers. Once it is matched in volume level, tune it so that it sounds the same for all frequencies than the two main speakers.

Finally, repeat the process for the rear speakers. First adjust the level of each so that the sound level they emit is the same as the front main speakers. Then calibrate the equalization of each.

Evidently, this is not an easy process to do by ear. Ultimately, you would want to have a spectrum analyzer with you as you perform these adjustments... but let's face it, most of us do not have this kind of costly equipment. Some newer home theatre amplifiers feature an automatic equalization system, built-in the device. You simply connect a microphone on the device and it "ears" the sounds it emits from its speakers and does the entire job itself. This is certainly a feature to look for.

Calibrating using a decibel meter

An easier approach is to use an instrument that can measure sound levels accurately instead on relying on your earring alone. This device is called a decibel meter and can be bought for as little as 30 dollars. A decibel meter measures sounds levels with high accuracy and is very sensible, often measuring levels in ranges from 30 to 130 dB. At 30 dB, you ear someone whisper at a few feet from you. 90 dB is the limit where sound can start causing pain and even permanent damage over an extended period of time. A normal conversation with someone within a few feet from you is in the range of 45 to 60 dB, which is probably the range at which you will end up calibrating your speakers.

The decibel meter will allow you to perform the volume calibration of each of your speakers more precisely and quickly than doing it by ear alone. It will only allow you to calibrate sound levels. It will not allow you to adjust the equalization of your speakers so that they sound equal in term of frequency bands from 20Hz to 20KHz.

The procedure is the same as doing it by ear except that this time, you must rely on what the decibel meter display is showing and forget about what you ear. Trust the device and adjust each speaker level one at a time, always ensuring that the dB level displayed remain the same, whatever the calibration sound level you initially choose. The only difference from the method given to calibrate by ear is that to adjust balance between your two front speakers, you will need to ensure only one of them emits any sound at any given time. The built-in white noise generator found on most home theater amplifier will do this for you.

Still, as these devices can be bought at relatively affordable costs, it is well worth the investment to consider buying a decibel meter to calibrate your home theater system to get the most out of it.

Calibrating using a spectrum analyzer 

Coming soon... 

Home theater amplifier units that feature auto calibration

Here is a list of amplifiers that feature an auto calibration system using a microphone.

Table legend:

See the Audyssey web site for a list of brands and models using their chipset.