I have read a few articles on how to use the spl meter and cant seem to figure out how to use it with my system, i have an option for speaker levels but it keeps switching between two speakers, then i have a test tone option that i can cycle through each speaker individually but here are my questions: 1) it says to put volume to avg listening level with a dvd or cd or some audio source, well i do and then when i go to test tones i don’t have 75 dbi worth of noise coming out of the speakers so i have to crank them up even more. To get to 75dbi, is this ok? 2) my front speakers, left and right do not have a +dbi range only negative so i have to use them as my starting point for my 75 dbi source correct or incorrect? 3) Should i point the spl at the speaker i am testing or in the air near my ear level? thanks.