Hey all,
I have a quick question about speaker level calibration. What source should I be using to create the test tone in order properly balance the speaker levels?

I can generate the tones via the B&K Reference 30, the Pioneer DMP-BD50, or using the "DVE: HD Basics" disc. I have used all three and I get different results from each. For example, I will balance my 5.1 system using the B&K's built in test tone. Then, when I put in the DVE disc, and run the test tone from there, it tells me my surrounds are ~5db too loud. Other discrepancies take place as well. Which is the most accurate?

I am using the RadioShack digital SLM with the weighting set to "C" and the response set to "slow". I position the meter at head level pointing slightly forward (less than 45 degrees). Furthermore, I set the dial to 70 and attempt to equalize levels at 75db.

Any help would be greatly appreciated. Logically, I thought that the DVE disc would be the best tone to use, however, I am beginning to question that notion. Thanks in advance!

First, aim the SLM directly upward so that you do not favor any particular direction/speaker.

Second, use a tripod/mic support for the SLM and measure 2-3 positions.

Third, resign yourself to the fact that pink-noise and an SLM may give you variable results regardless of the source since the SLM cannot distinguish the FR differences among the speakers and these are greatly affected by room modes.

All that said, I would probably use the test tones in the preamp or player, rather than the disc.

I would use the test tones of Avia or the Goldline test disc. They are properly band limited while most test tones on AV processors are not and may not be of the proper level. The RS SPL meter is very directional and will be influenced by speaker placement in relation to the meter. I would verify all of these levels with your ears.

Thanks for quick responses so far! I am still unsure as to which source to use, but my logical behind using the DVE disc was as follows:
a.) It is band limited pink noise.
b.) It uses Dolby TrueHD, which is what most BD's use.
c.) Ultimately, the sound I hear when watching a movie comes from a disc first (then passes through the preamp/amp/cables/etc). So by balancing tones from directly from a disc, I thought it would account for inconsistencies caused later on in the signal transfer.

However, when I balance from the disc, the surrounds seem weak. On the other hand, when I balance from say the player, the center sounds weak. Additionally, when I balance from the preamp, the surrounds seem too loud and the center is slightly weak. Granted, this is just observed by ear.

:confused:

If it helps, I am running the B&K to an ATI 1505 Amp. My Front L/R speakers are Green Mountain Audio "Europa". My center is a Magnepan "CC3". And my R/L surrounds are PSB "Alpha". It's a hodgepodge I know.

The B&K is set to DVD Audio Input mode. Furthermore, I have the number of speakers set to 5 (rears off). Speaker distances have also been set up (FR/FL=10ft, C=9ft, RS/LS=4ft). And my current speaker levels are as follows (currently balanced from DVE disc):
FR: -1.5
C: +6.5
FL: -3.5
RS: -4.0
LS: -3.0

I am sorry if that info is completely irrelevant, but this is driving me insane! Someone please help.

FWIW, I use the cal tones from my processor.

If none of the cals suit your taste, then use which ever method sounds best and fine tune it by ear from there.

It makes no sense to beat your head against the wall calibrating a system based on test tones and numbers if you don't like the results.

OTOH, I think quite a few people not use to a calibrated system initially think the surrounds sound weak when they are at the proper level.

I think a big part of the problem is the mismatched speakers. I always seemed to have issues with my center channel not being "loud" enough or not detailed enough ( always screwing with the trim levels ) until I got the matching center. I think people underestimate having a timber matched front end....important IMHO. rears not so much. just a thought

quite a few people not use to a calibrated system initially think the surrounds sound weak when they are at the proper level.

I couldn't agree more. Most people don't realize that 90% of what comes through surround speakers is designed to be ambience only. Only 10% is "effects." The intended purpose of the surround speakers is to immerse you in the scene. The worst thing you can do with surround speakers is set them up so they distract you from the story that's unfolding. Sure, it's cool when you see a knife fly out of nowhere and first you hear it coming from behind your head, but but if it makes you turn around and look at the speaker and go "Cool!" it starts to become counter-productive. When watching a movie, speakers should sort of fade away and not get noticed. That's one reason dipoles are popular for surround speakers... the sound does not appear localized, and so it doesn't draw your attention...

Some aspects of this I've been wondering about with the adjustments I make on my own and other people's systems:
1)Are you holding the meter in front of you as you sit in a listening position making the readings/adjustments? Your body could be muffling the sound the meter gets from the surrounds (but not the fronts) cuasing the meter to tell you those speakers need to be turned up...
2) What do people think: Adjust so speakers all put out the same level by holding the RS meter perfectly vertically (so it's perfectly omni-directional) or tilt it slightly forward so it favors front sound the way your ears do so you "perceive" equal levels on all speakers? I guess the question here isn't so much what people prefer, but if anyone here is familiar with what is done in produciton studios, so this can be replicated in viewing theaters...

2) What do people think: Adjust so speakers all put out the same level by holding the RS meter perfectly vertically (so it's perfectly omni-directional) or tilt it slightly forward so it favors front sound the way your ears do so you "perceive" equal levels on all speakers? I guess the question here isn't so much what people prefer, but if anyone here is familiar with what is done in produciton studios, so this can be replicated in viewing theaters...The issue is that having the levels for the speakers at the very same when measured with an unbiased (vertical, omnidirectional) mic then permits the HRTF (including pinna effects) to work properly. Tilting forward to get a better response from the front (as the HRTF does somewhat) is wrong.

I thought that the DVE disc would be the best tone to use

The advantage of the DVE test signal is it's filtered pink noise. The quote below is from my article All About SPL Meters (http://www.realtraps.com/art_spl.htm). There's more explanation in the article itself.

--Ethan

Pink noise is less irritating to listen to than white noise, and you can also play a pink noise test signal much louder without risk of damage to your tweeters. The Digital Video Essentials DVD that I mentioned earlier takes this one step further and filters the pink noise to contain only midrange frequencies. The bass response in most domestic-size rooms varies wildly with position - much more than in the midrange - so filtering the noise ensures more consistent and reliable readings when used for matching loudspeaker levels.

Great insight so far, I really appreciate it. The question remains though, what source out of the preamp, dvd player, or DVE disc, would provide the most accurate calibration?

Edit: Didn't see above post for some reason. It sort of sounds like the test disc is the way to go so far.

The issue is that having the levels for the speakers at the very same when measured with an unbiased (vertical, omnidirectional) mic then permits the HRTF (including pinna effects) to work properly. Tilting forward to get a better response from the front (as the HRTF does somewhat) is wrong.
Thanks... but forgive my naivety.... HRTF??? "Pinna" effects?

Thanks... but forgive my naivety.... HRTF??? "Pinna" effects?Pinna is the external ear part that you see. HRTF=Head Related Transfer Function.

These help us distinguish the direction of a sound source along with neural detection of timing and phase.

...OTOH, I think quite a few people not use to a calibrated system initially think the surrounds sound weak when they are at the proper level.


Some people also expect the surrounds to be active all the time or something is wrong.

One thing I've noticed is that it seems not too many discs are mixed at the same level. Neil young harvest DVD-A for example is too loud in the surround channels, so after useing the sound level meter for initial set-up, I find myself constantly adjusting the rears and occasionaly the center by ear anyway. Anyone else have this issue?

One thing I've noticed is that it seems not too many discs are mixed at the same level. Neil young harvest DVD-A for example is too loud in the surround channels, so after useing the sound level meter for initial set-up, I find myself constantly adjusting the rears and occasionaly the center by ear anyway. Anyone else have this issue?There are no standards for music recordings, so anything goes.

Question about -0, THX studio reference...
My Klipsch and Onkyo reach 75dbs at -5 from reference.
My sub runs 3dbs hot and my center is trimmed by 2dbs to match it with my fronts.
My rear "EX" surrounds are boosted by 2dbs to be the same as my sides.
Should I trim all channels by 5dbs so 75dbs- is 0, or leave it because only I need to know where 75dbs is?

Each channel will read 75dB at the 0 setting, and your subwoofer would have 105dB peaks or greater with no audible distortion. :)

does the DVE - HD basics for blu-ray have a 7.1 audio signal for calibration? im looking to use it to comfirm that 7.1 signals are being properly mixed into my current 5.1 setup and also to have it for testing any setup i would use in the future.

well i guess according to this review only 5.1 TrueHD

http://www.guidetohometheater.com/testtools/308dve/

"...the Blu-ray version has only 5.1 channels because of the complexity in synchronizing the TrueHD and Dolby Digital tracks. "

confirm?



anyone know where i can find 7.1 test signals then?

I haven’t been clear on one issue.
Ø DVD player for SACD-DVD-A & CD> Mch 6-cable analog. Calibrating with a disk (AVIA) using the player to calibrate your setting. Bypass setting in the AVR [extend In]. So your are using the DVD play’s trim and distance setting.
Ø Also, maybe sometimes use 6-cable analog for DVD Movies –including BR. Trying to get bass response more accurate.

#2
Ø Then Calibrate using the AVR’s test tone for coaxial playback for DVD Movies and cable box.

So, in other words two different Calibration setting. Because the AVR’s decoding logarithms for speaker distance & other internal switching, will be different then the DVD Player’s.
Is this accurate???