Axiom Home Page Forums General Discussion Advice from Axiom Owners Calibration

So, I know there's a ton of info regarding home theater calibration on this site. I have read through these step by step instructions and feel like I understand them. My two questions are pretty simple:

Is this the avia disk I need to get? (the general opinion here is that it is superior to the DVE disk?)

And do I really need a tripod for the SPL meter? Or can I just balance it on some makeshift low-profile stand?

This is the disc that i have and it has been excellent. Either the S&V or the Avia are good choices.

You do not need a tripod although it is handy for keeping the meter at the same spot. Ideally you want to have the meter up near your ear level since that is where your head will be when listening. Sometimes i just balance my meter on the back of the sofa.

Borrow a tripod if you can. If you can't, use blocks or books to create a tower that gets the thing a) to ear level from the usual best/preferred listening positon, b) isolated from side walls and obstructions, at least to the degree your head is when listening.

If you get the thing on a tripod (or some facsimile thereof), you'll be amazed to see how slight obstructions, such as the placement of your body relative to the meter and speakers, changes the calibration volumes. To really balance the side-to-side volume and match the center to the front mains correctly, a tripod is best.

Birdman

That's what I figured... I have some scrap wood lying around so I'll just put together a makeshift stand for it that has as little obstructing surface area as possible.

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I have some scrap wood lying around so I'll just put together a makeshift stand f

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Post some pictures of it for kicks.

Will see what I can do (no digital camera but maybe I can borrow one.) No promises.

To answer your question, yes that is the Avia disk. That, or the Sound & Vision disk that Chess uses, or Digital Video Essentials, which I use, will do just fine. Once you decide which disk to use, be sure to do a Google search to find the best price.

As the above posts show it isn't necessary to get a tripod. But if you want to, and if it fits into your budget, I got this one for $32 including 2 day FedEX shipping. It's just a lightweight one, but I really like it, and it does the job just fine. I was concerned about holding the meter steady, and at the recommended angle. Works with my digital camera, too.

Okay, I have a stupid question.

When you're doing this calibration, you have to be looking at the meter and holding your remote, right? So, doesn't the position of your body behind the listening position dramatically alter the readings on the meter, especially relative to the surround channels?

Do you just run it through a few times from different standing positions and kind of use the average?

My immediate response would be, yes that sounds like it would be a good idea.

I imagine that if you were really creative and bored (emphasis mostly on bored), you could mount a mirror on the cieling, and take the cushions off your couch. Then you could lie on the (cushionless) couch and look through binoculars at the mirror on the cieling to read the meter.

If you are exceeding small and your body would not make a good approximate for the cushions on your couch, you could wrap yourself in a down comforter or something.

If you are exceeding large, and your body similarly would not be a good approximate for your cushions, you could simply move the entire couch into the other room and lie on the floor.

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So, doesn't the position of your body behind the listening position dramatically alter the readings on the meter....

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Not a stupid question at all. And yes, your body position will have an effect. That's another reason I went with a tripod. I have a 6.1 setup. With the meter mounted on the tripod, I was able to move back and off to one side, when calibrating my rear surround speaker, while still being able to read the meter, thus minimizing the effect of my body. For the side surrounds, I just had to move back. The meter (I use the digital) can be read from a number of feet away.

That's quite funny Ringmir.

I guess I was bored (and creative?) In all seriousness, I will just do as Ajax has said and stand off to one side. I have the analog meter and the numbers are a little small but I should be able to read it. I think I read here a little while back that it was discontinued? If that is the case I guess I was lucky that the store by my girlfriend had a few of them.

Ringmir,
Radio Shack actually started producing the analog meters again, so it could be a brand spankin' new one you've got there.

Quite possible. It looks different than the analog meter listed in the step-by-step setup article. It is the same as the one on radioshack's website.

The one in the step-by-step article is the old, discontinued model. If yours is a smaller model with slightly curved sides, you've got the new one.

The new model number is (I think) 33-4050.

ringmir,
If you live in CA, you can get the S&V disc for about $15
at Fry's. Definitely, get a tripod. It makes adjustments
a lot easier. I got my digital SPL meter at Radio Shack
last week and everything came together. I tried calibrating
with the analog version, holding it with one hand while adjusting the speaker levels with other. That was a pain.
I got a lot of suggestions from the board members. Hope
that helps. Good luck.

stevel

Good God Men !!!
I just spent three weeks trying to make a decision on speaker system...Now i got to decide on a calibration disc. Your killing me here ; ) Do they come in rock/blues/country formats or must you deal with elevator music ; )

I have always wondered this. I am somewhat new to calibrating. I just re-read the step by step instructions on the first post here, and am still confused.

IF the first step is to set all speakers to 0db, then to turn up the MASTER volume on the front left speaker test tone until you hit 75db, won't adjusting the other speakers really just be at about +/- 1 or 2db? That's what I find anyway....am I doing something wrong?

I had a friend come over who installs HT's, and he calibrated it by ear and he turned up my fronts to about a +6 and my rears to +10db...I liked this sound better cause I could hear the rears more Are there other instructions I am missing?

Please help!!!

Setting all the speakers to 0dB in that sense isn't too important. You need to set the front left to 0, turn up the master until you register 75dB on the front left, and then in turn adjust each of the other speakers individually to 75dB. Does that make sense? Basically you are setting the relative offsets for each speaker with respect to the front left.

Also (at least on my reciever), the settings for equalizing the speakers are stored independently from any individual speaker ajdustment I make for a given playback format. So, once in the setup menu I've equalized everything, if I then start to playback something in Dolby Digital, all my speakers are listed as being at 0dB and I can turn up the rears if I want. But I know that at least I'm adjusting from an even starting point.

I was under the assumption that turning up the master to 75db tells you where the reference point is at, and then turn up each speaker using the individual levels at that same master volume determined by the front left speaker. SO, my front left is going to be 0 no matter what because that is adjusted using the master....correct? Then the others are adjusted using the individual volumes from -12 to +12 db... But, since I have the master cranked up to reach 75 db, the other speakers are really only being adjusted by about + or - 1 or 2 db....am I thinking incorrectly?

You set the front left to 0, play the front left test tone while increasing the master volume until your meter reaches 75dB. Then as you cycle through the other tones you adjust the speakers individually so that each of those test tones registers at 75dB. At this point, whatever master volume setting you were at is the reference level.

So, your front left will be at 0, correct. The others may require more than a +/-2 dB change though because they may be further from the sweet spot, angled differently, or have some odd reflecting properties due to things in the room.