Hi Alan,

That’s my thoughts exactly, I have never heard of as Johnny says trying to calibrate at dead center it does not make any sense as this is not as you correctly state where you sit.

(Sorry guys for the long post)

With regards to the reference levels, I have just been on the phone to a THX certified installer a gentleman by then of JP was kind enough to let me pick his brains for about 45 minutes. In a nut shell, with regards to calibrations this is the what he said about the 85 vs 75db. 75 db is the calibration guideline for theater, for music the guideline is 85db. The reality is that we listen to a mix of both and unless you have a dedicated theater room there is really no right or wrong. If your manual states 75db (as does my Denon) that is where it was calibrated to at the factory and the levels at which their THX certifications were done. JP also stated that he will change the calibration value for a given room depending on the size and response (live ness) of the room. As for using the meter, Digital is fine, make sure that the meter is set to “C” weighted and slow response. The meter should be placed in your seating position (not dead center) and the meter held vertically not horizontally. If you do not have any way to hold the meter in this position then stand behind your seating position and hold the meter at arms length so that it is in roughly the same position as you would be when seated. You should also sweep the meter left to right and adjust for an average of 75db, or an average of whatever level you are using, again be sure that the meter is held vertically.

I hope this helps

Regards
John.


Last edited by john_henderson; 10/04/02 09:28 PM.