Please explain the need for, and how to calibrate the audio for my HT System?

The main "calibration" function is to set the loudness of your speakers to the same level. The room will have an effect on the loudness of each speaker. So will your distance to that speaker.

The test disc will play sustained sounds through each of your speakers in turn. You set each speaker level via your receiver's remote control so that it reads the same sound level as all the other speakers. This assures that you are hearing all the speakers at their correct levels.

- Terry

Calibration is one of the most important steps to having a properly set up system. While your various speakers may end up being placed at different distances from you, adjusting the volume level of each speaker and delaying the sound of each channel can give the impression that all your speakers are equidistant from you in a neat circle. They will all be equally loud and their sound will all arrive at the same time.

For the moment you can skip the test disc since your receiver has built in test tones to help calibrate speaker levels using the SPL meter you got from RadioShack. See the section of the instruction manual under Advanced Setup, which also explains how to dial in speaker distance settings (you just need a tape measure for that).

Once the levels and distances are calibrated, you should configure all your speakers to Small and set the crossover to 80Hz (it is currently set to a default of 100Hz). This way, low frequencies that your speakers cannot reproduce properly will be filtered away and re-routed to the subwoofer for proper reproduction.

Good Luck,
Sanjay

Another thing to calibrate, if you can, is signal delay to each speaker. Speakers are supposed to be equidistant away from the listener. When they are not, you can compensate by adding digital delay in the receiver. This can be done before the DACs, so there's no degradation in quality.

After that, you may want to look into some EQ to compensate for room modes and nulls, but it's probably a better idea to get some bass traps, acoustic foam, or similar treatments to try and take away the worst offenders.

Great explanation, Sanjay. Much better than mine!

- Terry

Perfect; that's exactly how you calibrate levels.

Set your SPL meter to "C" weighting and "Slow" response. Each speaker (and the subwoofer) should measure 75dB on the meter when playing your receiver's built-in calibration noise.
That's fine. It doesn't matter what the levels on your receiver end up at (or whether they are positive or negative numbers) just as long as all the speakers are equally loud at your listening position.

Don't forget to dial in the distance numbers and set the crossovers to 80.

Sanjay

The internal test tones are fine. You will find that just about any input you select will have a different volume level because the output signal level from various devices may or may not be the same.

You may be able to reduce the signal level coming out of the cable box so the levels are more closely matched.

Also, you don't have to set the volume at the "calibrated" level to use the system. It's merely a reference point to a known volume. Hardly anyone I know of watches everything at reference volume - just set it to what ever volume pleases you (and doesn't get you in trouble ).