Originally Posted by quigonsir
honestly though calibrating sub level to 82.5 with avia is a little non useful. The reason I say this is b/c the meter may read 82.5 in say the center of your room, but then once you move a foot in either direction the meter reading changes, or if you sit closer to a wall the meter may spike and you may have to turn the sub down to ridiculously low levels to get 82.5. I think using an spl with sub calibration is a little useless. I wish there was a better way to do it. I know you can use a spectrum analiyzer, but that can get very confusing and expensive. I guess it's up to your ear what is best, but some people may like bass so high that it is bad for the sub. I am always a little fearful that the pounding bass I like is too much for the sub, but I think these things were designed to pound, especially if you have an SVS!! For me, in the center of my room, i get about 82.5 reading, but at my seating position get about 86.5 or 87 on the meter, who knows??
Well, part of what Audyssey's MultEQ XT is designed for is to make response more even from seat to seat (i.e. eliminating "sweet spots"). Yes, you're correct that bass can vary greatly from position to position. For instance, near room boundaries, you'll get a boost. That's just an unavoidable truth of the nature of low frequencies. This sort of thing is why audio is more complex than just "set it and forget it", and is why you hear people suggest corner-loading subwoofers to get the smoothest overall response. It's also why people who expect Audyssey to work miracles without the careful setup that SHOULD take place beforehand will almost always be disappointed in the results.
If you want to make your head swim, here's another little nugget to complicate your life: Avia's subwoofer tones are actually located in the main channels, not the LFE channel. So if you set all channels to full range, none of Avia's tones will even come out of the subwoofer. They do this so you can assess bass management in the system, and so long as you're crossing your speakers over at 80Hz or above, you're likely getting accurate results. The rub is that because Avia is dependant on the system crossovers, setting the crossovers below 80Hz makes the tone dependant on both the subwoofer and that individual speaker, introducing the potential for phase cancellation problems that can throw off the reading. So while Avia is a great tool for system verification, certain variables may make it better for you to just use the internal tones (which, by the way, should all read 75dB on a C-weighted meter on all channels, subwoofer included... and those tones are NOT crossover dependant).
My big question: Why are you calibrating for the center of your room anyway? Calibrate level for where your ears will be when you use the thing! And as I said before, the final setting should be determined solely by your listening preferences... NOT by any meter.