Auto-calibration vs. SPL Meter

adam2434

This has been suggested numerous times here, but folks should still consider running a SPL meter calibration, even if they have an auto-calibration mic/system.

I recently did a SPL meter calibration with my Pioneer Elite's test tones and the test tones from the Sound and Vision Tune-up DVD. Both produced similar results, but were significantly different from the auto-calibration. I always felt that my surround channels were somewhat weak; the attached data shows why.

Pioneer's auto-calibration is supposed to be pretty good, but trusting the SPL meter, I'd have to say the auto-calibration is significantly inaccurate.

Mic/meter placement was consistent within an inch or two for all. Intentionally varying the SPL meter position about a foot in any direction only produced about 1 dB of difference on the SPL meter for any channel. (This makes me glad that I don't have to strap my head down to the sweet spot when watching a movie. )

I found the Sound and Vision Tune-up DVD's test tones to be less convenient to use than my receiver's. Using the receiver's tones only required the operation of one remote control and were much easier to cycle through.

I've switched my system to the "SPL meter with receiver's test tones" calibration. It's been a while since I've used a SPL meter; it's educational and kind of fun (and really pretty easy for those on the fence about this).

mldennison

adam,
thanks for sharing that. you said that your receivers tones and the DVD tones were similar, how close exactly were they? i have heard people that say the receiver tones are fine and some that say they arnt, just wondering what you consider similar.

mike

adam2434

Could you open my attachment? That will show you.

I don't know which ones are more accurate, but my receiver's were much easier to use.

mldennison

whoops, sorry, didnt see that, they do look pretty close...thanks

Early B.

I never use the auto-calibration. I always felt it was a marketing gimmick. If the SPL meter isn't broke, don't fix it.

Holydoc

adam2434 wrote:

Could you open my attachment? That will show you.

I don't know which ones are more accurate, but my receiver's were much easier to use.

To tell you the truth Adam, if you are calibrating your system for DVD movie enjoyment, then the calibration done with the DVD player that you are going to use is more accurate than your receiver testtones.

Matter of fact, my receiver test tones do not hardly come close to my AVIA DVD test tones. Calibrating with the AVIA DVD allowed me to have a more active and realistic soundstage.

Go to your local DVD rental shop and rent the AVIA test DVD. It is simple to use, walks you through the tests, and is much more accurate than depending on the fact that your receiver will play your media the same loudness as your built in test tones.

aaharvel

Holydoc wrote:

To tell you the truth Adam, if you are calibrating your system for DVD movie enjoyment, then the calibration done with the DVD player that you are going to use is more accurate than your receiver testtones.

IF you're using the multi-channel analog outputs on the back of your dvd player to start with, and not the digital coax or optical hookup from your receiver.

That is a big if. Quite frankly the only ones I know to use this method are SACD and DVD-A users, or if they're receivers don't house Dolby Digital or DTS decoders. Virtually all of them do.

sickicw

I have experimented with many ways of calibrating my system and found that one I like the best is using my onkyo auto equalization and auto setup. I have used the following: radio shack meter & test CDs, rane parametric eq, some other digital parametric eq (forgot the name), and a $1300 denon receiver auto-eq that uses up to 6 mic positions. I always liked the onkyo better than them all. The following is probably the reasons why: 1) it sounded the best, 2) was the easiest to do, 3) I swap around equipment quite a bit and like to quickly auto-eq everything when I am done to demo the setup. 4) my setup makes my speakers way too bass bloated and not enough mid and high frequencies and the onkyo easily fixes this. 5) the higher end (rane) parametric eqs are very expensive and not easy to set to small frequency bands. 6) The radio shack meter is not able to be calibrated and I have no idea how accurate it really is at higher frequencies. 7) the engineers at onkyo supply the mic and should have an easy time figuring out the best way to eq the signals coming into the mic. 8) I am lazy and feel technology is at a point to where it should be able to do this job for me

Early B.

Got a question -- when using an SPL meter, does it matter how accurate it is? It seems to me that all you're trying to do is get the speakers at the same level.

Another thing I prefer to do is run my center channel a couple decibels higher than the other speakers. Works well for movies, especially for dialog only.

adam2434

Holydoc, I didn't know you could rent the Avia DVD. I'll have to check that out.

Fortunately, my DVD's test tones and receiver's test tones produced very similar results (see attachment in 1st post), maybe even within measurement error if I repeated the process several times.

Another variable could be the frequency range of the test tones. The tones on my set-up DVD and receiver sound very different. How these different sounding tones interact with the room and SPL meter's sensitivity could also be factors in calibration differences.

Early B., I don't think absolute accuracy is as important as precision/repeatability. If it's not perfectly accurate, your system may be off a dB or 2 from a reference level - really no big deal. However, if it's precise/repeatable, you can still get the channels balanced properly, which is very important.

krabby5

I used the auto setup from my Elite 72 and am very satisfied. I also used the spl meter to test..

I ended up liking the auto-setup better. The newer Elites have a 9-band eq, standing wave adjustments, reverb check, and acoustic calibration eq....

works real nice..

I don't know..maybe if someone more experienced than myself came over and manually set my system up, it would sound better with the old methods...but that isn't going to happen, so I'm happy...

Holydoc

adam2434 wrote:

Holydoc, I didn't know you could rent the Avia DVD. I'll have to check that out.

Fortunately, my DVD's test tones and receiver's test tones produced very similar results (see attachment in 1st post), maybe even within measurement error if I repeated the process several times.

Another variable could be the frequency range of the test tones. The tones on my set-up DVD and receiver sound very different. How these different sounding tones interact with the room and SPL meter's sensitivity could also be factors in calibration differences.

Early B., I don't think absolute accuracy is as important as precision/repeatability. If it's not perfectly accurate, your system may be off a dB or 2 from a reference level - really no big deal. However, if it's precise/repeatable, you can still get the channels balanced properly, which is very important.

Adam,

Here is a link to Avia on Blockbuster.com.
http://www.blockbuster.com/catalog/DisplayMovieSpecialOffers.action?channel=Movies&subChannel=&movieID=103669&displayBoxArt=true

I do agree that you probably are safe either way you go since your test tones were so close together.

Either way, set it the way you like. That is what matters most.

opus

aaharvel wrote:

IF you're using the multi-channel analog outputs on the back of your dvd player to start with, and not the digital coax or optical hookup from your receiver.

That is a big if. Quite frankly the only ones I know to use this method are SACD and DVD-A users, or if they're receivers don't house Dolby Digital or DTS decoders. Virtually all of them do.

Hey Aarhavel, could you explain this please? Trying to get my "learn on" as they say.:)

adam2434

Holydoc wrote:

Adam,

Here is a link to Avia on Blockbuster.com.
http://www.blockbuster.com/catalog/DisplayMovieSpecialOffers.action?channel=Movies&subChannel=&movieID=103669&displayBoxArt=true

.

Thanks, I checked it out and unfortunately no stores in my area have it.

adam2434

Krabby, how did the channel levels compare between the auto set-up and the SPL meter?

Holydoc

adam2434 wrote:

Thanks, I checked it out and unfortunately no stores in my area have it.

You don't need a store. You have the internet. That link takes you to the online rental store. Just like netflix.

Maestro

I've used the auto-EQ of H/K and the SPL meter as well. I must say that I do like the results of the H/K calibration better. It really managed the "room" acoustics very well. Like the auto-navigation systems, the engineers are really getting the upper hand on the technology to make it easier for consumers to enjoy their toys!