Axiom Home Page Forums General Discussion Home Theater SPL Meter + Calibration Question:Analog/Digital

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...