3 calibration discs, 3 different sets of results! (1 Viewer)

[Harry Lincoln]

I was playing around with my system yesterday and I ran a speaker level check using the internal tones from my yamaha amp, the center was up by 6db and the surrounds down 2db from the mains. Last time I calibrated the system I used the Ultimate DVD platinum so I popped that in and ran the test again, all speakers were level matched. I know that it is better to use a disc to set levels rather than the receivers internal tones so I left the setting as is and started playing around with the TPM DVD. I got into the THX optimizer and ran the test tones again, the results this time the center -2db and the rears at +2db from the mains (There is a note on this screen that says the tones are not intended for speaker level matching). I then popped in a third setup disc, one that I got for free with a DVD mag, this time the center was +1db and the surrounds +1db.

Im thinking that this is being caused (mastering errors aside) by certain frequencies in the test signals being excited by room acoustics, as all the tones seem to be in a different freq range from each other. So it seems the only way to do a true calibration is to first get a flat frequency response from all speakers using equalization and then calibrate using a setup disc(s) - all three DVDs should then give the same results.

Sounds like a pain in the arse! So much for speaker calibration being a five minute job.

Harry.

 

[Jeremy Anderson]

Well, if you want to hear something even more bizarre... My brother has the Avia disc and it looks silver. I have the Avia disc and it looks gold (and the two cases have different types of hubs). If I put in his Avia disc and calibrate with it, then put in my copy of Avia for comparison, my copy produces a +2db difference in the surrounds. We're talking tripod mounted SPL meter, nothing moved or changed. I really can't figure it out! But calibrating with my brother's copy yields the same results as the internal tones on my receiver, so that's the one I'm trusting.