Greetings!

I've got an analog and a digital SPL Meter from Radio Shack.
Using AVIA's test-tones, They have a recommendation to calibrate the system so each speaker registers 85dB.
The problem is using the SPL meter, I can't get the signal to remain constantly on 85dB, and it is frusterating me...its sometimes between 84 and 86dB...and I know that Dolby usually also recommends to calibrate your speakers at 85dB or sometimes 75dB, but how much room/leeway/headroom are we allowed to have, before the dB level of setting up a home theater is too loud or too soft... because I cant get it to say at 85dB...it constantly jumps up and down on the decibels...

Thank you so much for anyone trying to help...

I usually go with, "if it's dancing around the level I want, it's close enough."

But there are far more exacting people than me out there.

When using the analog meter, do you have it set to Slow response? That will damp out the bumps and give you an accurate average.

I'm with you on this Ken, plus or minus one db is close enough for me.

Yep...I've got it set to C-Weighting;Slow Response...and it still jumps around...

If you're using the digital meter, you have to set it to "slow" each time you turn it on. It automatically defaults to "fast." PITA!

Thanks Ajax...But I've done that too!

Mitch, in addition to the above replies, keep in mind that the claimed accuracy for the RS meter is +/- 2dB, so don't be overly concerned with the precision of your read.

OK, these were my results after I calibrated my Harman-Kardon AVR65 receiver using the Radio Shack digital SPL Meter at 75dB.
L=0dB
C=0dB
R=-3dB
RS=+5dB
LS=-4dB

if sound is usually twice as powerful at 3dB...would it be better to just set the surround speakers both at +3dB, instead of where it is now, or would that be ruining the general purpose of calibrating a home-theater at 75dB?

Trust the meter and trust your ears. Does the surround sound stuff sound unbalanced? Because if it doesn't now, it certainly would if you set both to +3 dB.

Please describe your room layout, it must have something to do with that....If your running test tones from your receiver and calibrating everything to 75dB's and that is your end result, you would be defeating the purpose if you changed them to the same readings. It is suprising you have such a difference on the surrounds though, can you discribe their placement. I'm guessing the right main is in a more open location compared to the left main?

Thank you for making that point, kcarlile, I will definately keep it as it is now!