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Stupid ? what does reference level do. (1 Viewer)

John Garcia

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ThomasL - try earplugs. You don't actually need to LISTEN to the tones to read the SPL meter :D But I know what you mean. The S&V disc pretty much concurrs with your statement - basically, as long as the speakers are set evenly with respect to eachother, the sound will be ballanced, regardless of volume. 85db or 75db are what one is shooting for, but that does not mean you will ever really listen to it at that level.
 

jeff lam

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Phil,

I don't understand what you are saying. You must have misunderstood my post. I simply said the VE DVD test tones playback at 30dB under reference. That's why the 75dB value is used(75+30=105dB=reference level). To achieve this, simply use your spl meter to measure 75dB. Now this volume is your reference volume and should produce peeks of 105dB when watching dvd's.

NOW it seems that people are suggesting that whatever volume setting you're on when you calibrate the avia test tone IS reference level when listening to regular source material. so, if i get 85db with avia at -20 on my volume, playing back "episode 1" or "gladiator" at -20 will give me peaks of 105db/115db.
John, you got it! If you still think it's not loud, double check your calibration. If listening at these levels you measure peeks at about 105dB-115dB, you are correctly calibrated. If you still think it's not loud then you have hearing damage because anything over 110dB will damage your ears. Check the mannual for the SPL meter and there is a chart as to the exposure of high level spl's and how long you can listen to these levels before hearing damage occurs.

BE CAREFUL!
 

Phil Iturralde

Screenwriter
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Jeff - you're correct! I read your earlier post in haste, ... sorry, must of been the hunger pains clouding my vision! :b Cool "Reference Level Pink Noise and Playback Level" gif though!
Just had 'terriyaki chicken' lunch plate @ our local Japanese restaurant, . . . I'm doing better now!!! ;)
Phil
 

Vin

Supporting Actor
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I would say if you search for my name and Ref Level or Avia on this forum, you'll probably find more than 30 posts explaining the concept in a dozen different ways!
And I'll bet that's how most of us came to understand the concept.....in your absence, however, we've managed to come with at least another dozen different ways to explain it! :D
Vin
 

jeff lam

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No Vince, I would have said you should have gotten into this one earlier and set the record straight. Nobody can explain thing quite like you around here. You could have turned this 25-post thread into a 2-post thread and everyone would be clear on this whole reference thing.:D
Phil,
Why'd you have to go and say that for? Now I need a plate lunch. Back in Hawaii where I grew up we had the best plate lunch places around. L&L drive in finally moved out here to CA in the south and one in the Oakland area. Any good ones in the south bay?
 

Phil Iturralde

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Thanks Vince for all the links!! Was wondering when you'd finally pipe-in!!! :)
Jeff - my brother and I went to Matsuyama (sp?) restaurant in Milpitas - on Abbott Ave. off Calaveres Blvd. It's a little mom & pop Japanese restaurant w/excellent beef, pork, chicken, etc. lunch plates (including soup, rice & salad $6.35) as well as the usual shushi list.
Interestingly, it's not listed in Yahoo Yellow pages, but the restaurant is directly across the street from Kowloon Chinese Restaurant - 24 S Abbott Ave. (scroll down the list for map)
Might be there again this Friday for lunch!
Phil
 

John Doran

Screenwriter
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Jan 24, 2002
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vince,
i read some of those posts, including your guide at cheaphometheater.com. what was said was typically something similar to what you said in this thread :
Ref level is a measure of output- and using the tones on Avia or VE as directed will determine the needed volume position on your receiver for ref output.
that particular statement is totally clear if you read it already knowing the answer. otherwise, it's ambiguous.
it can mean, for instance:
(1) using the tones on Avia or VE as directed will determine the needed volume position on your receiver for ref output because since you know what volume-level gives you 85db, it's easy to know what volume setting will give you 105db - just add 20.
or
(2) using the tones on Avia or VE as directed will determine the needed volume position on your receiver for ref output because the volume level that gave you 85db just IS reference level.
turns out #2 is the right interpretation.
anyway. the fact that i've read about all of this stuff ad nauseam in the past and again now and still didn't understand it means that it's either not that simple, or it is, but just not explained as clearly as it might be.
it probably also means that i'm really stupid. :frowning:
whatever. it's probably from listening to music and movies too loud too long...
- jd
 

Jon D

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Just to clarify something mentioned earlier: just because you have your volume set at the 'reference' level does not mean that all movies will have peaks of 105 Db. The Phantom Menace is notorious for being relatively quiet at 'calibrated' levels while Gladiator is painfully loud. Personally, I use reference level as a starting point, and adjust my volume from there until it sounds how I want it to. I turn TPM up, and Gladiator down.
 

Vince Maskeeper

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John Doran,
Your point is well made- I have edited my one sentence above in hopes of making it more clear. The misunderstanding you cited does come up often, but I think if anyone slows down and really reads what is being said- this misundersatnding would be avoided often.
Also- I would still argue that my many posts that strech on much longer than one sentence (and some would argue on much longer than they need to) offer up a very clear explaination of how the process works... certainly much better than can be achieved in one sentence.
For example:
is what "ref level" means.
To determine ref level, someone could supply you with test tones created at absolute MAX level possible, and you could balance your volume knob so that you get 105db from each speaker with these tones.
However this would suck, and be painful on the ears.
So they created tones a specific number of steps below that maximum for you. The tones on AVIA are 20 steps below max (max should be 105db, so 20 steps below means 85). The tones on VIDEO ESSENTIALS are 30 steps below max (max should be 105db, so 20 steps below would be 75).
So, when you use AVIA- you are hearing tones that are exactly 20 steps below the maximum. So, if you calibrate your system to play these tones out at 20 steps below max-- you have set your system to ref level. With your volume set as calibrated with AVIA, the loudest possible sound on DVD will come out of your speaker at 105db!
So, yes, your number 2 is the correct assesment.
-Vince
 

Vince Maskeeper

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Just to clarify something mentioned earlier: just because you have your volume set at the 'reference' level does not mean that all movies will have peaks of 105 Db. The Phantom Menace is notorious for being relatively quiet at 'calibrated' levels while Gladiator is painfully loud. Personally, I use reference level as a starting point, and adjust my volume from there until it sounds how I want it to. I turn TPM up, and Gladiator down.
Actually- to be even more precise-- just because these two soundtracks are louder/quieter than one another doesn't mean either does not have a 105db peak!

Both might very well have a 105db peak somewhere in the film- despite the perception of volume differences.

The issue you're seeing is the idea of average sound level. Gladiator certainly has a much higher average level than TPM, but this may/may not have an effect on the peaks in the course of the soundtrack.

Of course, try playing back a VHS tape with your volume at the level you listen to DVD... you will go deaf. VHS audio is compressed so that all the sound is in the highest 6db (so on a calibrated system, the sound would range between 105db peak all the way down to 99db at the quietest!).

This of course is a completely different issue- but important to understanding the concepts we're dealing with here.

Ref level playback system certainly doesn't dictate what level the film will be reproduced-- and not all films will ever approach the max peak allowed on Dolby Digital. However- ref level is a good starting point and often the level the mixers of the film were using when they created the track. It also serves as a level playing field, so to speak, when comparing audio experiences with other people half a world away (like often happens here on the HTF).

-V

PS: I do have to say that it is a very nice suprise to find that many of the posters in this thread actually understand the concepts and offer accurate answers!

A year ago I usually stayed out of hardware due to frustrations with how much false and misleading info was spouted as certain fact.

John Kotches, Vin, Phil Iturralde & jeff lam all obviously grasp this issue pretty firmly and did a pretty good job of trying to explain it. This is a ginat step forward for the HTF, IMHO, as just a year ago a question like this would bring out 20 wrong answers and wrong concepts. Thanks guys!
 

John Doran

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vince,

Also- I would still argue that my many posts that strech on much longer than one sentence (and some would argue on much longer than they need to) offer up a very clear explaination of how the process works... certainly much better than can be achieved in one sentence.
you're right, of course. but i think it often takes one unequivocally clear sentence or expression of the key point to overcome contrary assumptions readers might be burdened with.

for instance, in my case, i was operating under the assumption that the volume level at 85db with avia was 20db lower than reference - as you put it, 20 steps below reference. as a result, any time i read anything that was even remotely capable of being understood in that way, that's the way i understood it. you know?

but, again, you're right that a slower, more careful reading (by someone smarter than me) would doubtlessly have provided me with the right idea, since your explanations actually are very good examples of clear, informative, and insightful writing.

but thanks for taking the time, despite the frustration you must sometimes feel at the silly mistakes made by people like me.

- jd
 

Vince Maskeeper

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John,
You certainly make a good point- and I do see where the confusion comes from. I will do my very best to make sure I am as clear as possible on this issue in the future.
See, there you go, now I have to come up with another dozen ways to explain it ;)
-Vince
 

ScottAndrew

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Dec 21, 2001
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For what it's worth, I realized that I was calibrating to 75dB using 85dB tones, so what I thought was reference is 10dB less. That's why what I thought was reference isn't necessarily all that loud (and my sub didn't blow up.) 10dB louder would be pretty deafening. I'm not going to re-calibrate, though; everything's balanced and it sounds fine.

Scott
 

Vin

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For what it's worth, I realized that I was calibrating to 75dB using 85dB tones, so what I thought was reference is 10dB less.
Scott, Video Essential's test tones (this is the disc you used, isn't it?) are 75dB, Avia's tones are 85dB.

Vin
 

ScottAndrew

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Dec 21, 2001
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It would have helped if I had correctly stated which DVD I used. It was Ultimate DVD Platinum. (They all sound so alike!) I read that the tones were at 85dB.

Scott
 

Phil Iturralde

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...I was calibrating to 75dB using 85dB tones...
Maybe, but then again, if Ultimate DVD Platinum didn't specifically state 85 dB in the program notes or in the DVD narration, then, it's probably per Dolby Lab's 75 dB home standard. The easiest way to check that is by comparing your AV Receiver's Dolby Digital internal test signal REF Level Mark vs. Ultimate DVD Platinum Dolby Digital REF Level Mark. If both Volume knob REF Level Marks are identical or relatively close, then 75 dB is the correct Test Signal playback.
Now, if the Ultimate DVD Platinum Dolby Digital REF Level Mark is really low, say up to 10 dB below your AV Receiver's internal Dolby Digital test signal, then 85 dB would be the correct Test Signal playback.
Example: Using AVIA, my 85 dB playback SPL REF Level Mark is "identical' to my, Video Essentials 75 dB playback SPL REF Mark on my Yamaha Volume Control knob.
Edit: Thanks Vince for your untiring explanations, help and FAQ Newbie creation!
Phil
 

JohnWA

Auditioning
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Jan 11, 2003
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Of course, try playing back a VHS tape with your volume at the level you listen to DVD... you will go deaf. VHS audio is compressed so that all the sound is in the highest 6db (so on a calibrated system, the sound would range between 105db peak all the way down to 99db at the quietest!).
Oh man I'm having an epiphany. My Parasound AV2500 has a nice auto calibrating feature that uses internal pink noise to do what you guys have been talking about. However when calibrated, at a given volume, DVD's are quite a bit quieter (bad grammar) than everything else plugged into my receiver. (CD player, Sat TV, VHS, Etc.). This has always concerned me. Are you saying this is normal? The calibrating feature in my Parasound is specifically designed for a DVD source which is "quieter" than other audio sources?

If I'm correct in the above, why is it DVD's play quieter at a given volume than everything else. Or am I still confused......

Thanks
 

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