Axiom Home Page Forums General Discussion Home Theater Avia Disc & Sub-Woofer Calibration...

This is reference to the first Avia calibration disc.

In Chapter 7 (Subwoofer Calibration) the disc goes through a series of alternating high and low frequency pink noises from left main to sub, center to sub, right main to sub and so on until all speakers have gone through this pink noise process. Whenever I do this the sub is reading my pre-setting of 75/75db for the mains but 61/75 and 60/75db for the center and surrounds. The disc instructions says to calibrate the sub with either the receiver or the sub's amp so that you'll get the same db reading on the sub throughout all of the speakers but this can't be done, if I calibrate the sub to 75/75 db with the center and surrounds the sub goes through the roof whenever the mains are played. Am I missing something here?

In the past I've always calibrated all speakers using pink noise and set all db's the same.

Speakers to set to small, sub (EP600) is set to -7 db on the receiver and the crossovers are as follows, mains (80s) to 60, center (VP150&100) and surrounds (QS8s) to 100.

Wasn't there something about the calibrations being off on the Avis discs?

I really can't remember Jay, do you believe it may be a fault with the Avia calibrating disc?

I've never understood that part of the Avia disk either. I try and calibrate it to my mains then eventually give in to the temptation to adjust it myself anyways.

Also, I don't have the adjustment table for my particular SPL Meter's inaccuracy for LFE. I have seen downloadable tables for the Radio Shack meter but that is a bit of a Holy Grail device here in Canada considering we haven't had a Radio Shack in many years since they pulled out and got replaced by "The Source".

Same here.

I usually calibrate the subwoofer to my left main and just skip the subwoofer calibration for the other speakers. My thinking was the additional test sweeps for the other channels was if you were say running stereo, tri, quad etc… subwoofers you could calibrate each speaker + subwoofer pair individually. Never read that anywhere but it was the only thing I could figure it would be useful for.

Murph, if you are interested, you can get the Radio Shack SPL meter through Sonicboomaudio.

I will have to look around to see where I read the avia disc is out of whack.

I could be wrong and without going back to the disc I thought it stated the calibration process was for a single sub system. Like you Grunt, it seems to me like that particular calibration process could be designed for a multi-sub system.

While we're wallowing around in calibration, I'd like to ask a stupid question.

The RS analog meter has ranges for 60, 70, 80 db, right? And on the meter itself, we see 0db as the midpoint, right? So, isn't a reading of 0 on the 70db scale, well, 70db? If so, why do we try to calibrate to 75 instead of 70 or 80?

I dunno Tom, I have a digital meter. I believe the apparently broke Avia disc also states to calibrate above 70db, so I just calibrate our stuff to 75.

That's how I read it, Tom. If I'm misreading it, then I'm listening to stuff substantially louder than I thought...