Reference Level

kberg

Ok guys, here we go again. I think I need some of John Anderton's "clarity" from Minority Report regarding the use of the term "reference level".

I used the S&V disc to calibrate my speakers and sub, using 75db to "balance" each speaker. Everything started off at 0's on the receiver and -5 on the sub, per Doc's previous posts regarding how to calibrate speakers. Now, I know my speakers and sub are calibrated correctly in terms of being "balanced" (at 75dB or I suppose ANY level I wanted to balance them at), but I'm still unclear when someone says they "played a DVD near reference level" - what does that mean? Is that some DVD-specific volume based on achieving a certain maximum SPL level for that particular DVD, like say 115dB peak, or something like it? Does reference level (in terms of how loud I can increase the volume on my receiver) vary depending on the DVD I am watching, because of the SPL peak differences per DVD? I'm almost certain it means that I can crank up my volume quite a bit more than 75dB, but how can I tell how much more I can go before I risk blowing drivers?

I thought I knew what reference level meant, but it appears I don't...yet.

STUFFMD

Hey Kberg.....
What is called "Refrence level" on my reciever is around 75 or 80 on the volume nob. That's the volume at which the Pink noise or whatever the tone is that is used to calibrate your speakers with the SPL meter. I am sure refrence levels are different on different recievers but in a similar range.
If I crank my reciever volume to this level it doesn't say 75- the word refrence comes up.
Stuff

Dr. Spec

I'll field this in the am - too late tonight.

Doc

Dr. Spec

Kev,

Dolby reference level is defined as 105 dB bass peaks from any surround channel, and 115 dB bass peaks from the LFE channel. If the surround speakers are set to “small”, the subwoofer is required to handle both low passed surround channel bass and the LFE channel. In the event of a simultaneous bass peak in both a surround channel and the LFE channel, the subwoofer would be required to deliver a 121 dB bass peak.

You should calibrate S&V to 85 dB all around at Master Volume 00. That way you can compare notes to everyone else who is calibrated to RL.

You will not be able to play all DVDs at Master Volume 00; it is far too loud in most cases. But whatever master volume you DO use, if you are calibrated to 85 dB on S&V, then I can set my own MV to the same level as yours and experience the same approximate SPL in my own HT room.

The Avia and S&V require 85 dB, and the other discs require 75 dB. It has to do with the level the test tones are mastered at on the disc.

Doc

kberg

Originally posted by Dr. Spec
You should calibrate S&V to 85 dB all around at Master Volume 00.

Sounds good! I take it that what is meant by "Master Volume 00" is whatever volume is displayed on my receiver when the center speaker is kicking out an 85dB test tone when set to "0" at the receiver, and the remaining speakers are adjusted to 85dB at the receiver, yes? I adjust the sub at the sub to +3dB, or about 88dB.

Dr. Spec

Yes, many of the better AVRs default to Master Volume setting 00 when the internal test tones are activated.

The master volume on my 3803 shows decreasing negative numbers as the volume increases, and eventually it hits 00 and then starts going into the positive range.

To make life easy when calibrating with an external disc like Avia or S&V or VE, most people manually set the Master Volume to 00 as an easy to remember benchmark. Then they adjust the individual speaker levels until they get 85 (or 75) dB for all the surround speakers.

If you don't have that type of read out on your master volume, you will have to manually do the math in your head when you express your volume settings on playback and say for example "I was running SW-AOTC at 18 clicks (i.e., whole digit numbers) under Reference Level".

Whereas I can say simply cite my straight volume setting without doing any math since I am referencing off a 00 setting for calibration. So I'll simply state for example "I ran SW-AOTC at -12".

Of course this still brings into question the matter of a master volume truly giving a 1 dB increase or decrease with every whole number change in read-out. My 3803 displays 1/2 digit increments and is very accurate, with each 1/2 digit representing a true 1/2 dB change as confirmed per my SPL meter.

And finally remember Reference Level is more defined by the SPL level during playback than it is the absolute volume setting. We calibrate to the same standard only to achieve parity and a benchmark, not so we can all arbitrarily set our master volumes to 00 and say with confidence we are playing back at reference level. There is no one standard for mastering the overall volume of DVDs - some are hot, some are just right, and some are cold.

Doc

malikarshad

I recenly calibrated my system to RL as suggested by Doc. I have Denon 3803 as Doc so I set the master volume to 00 but the only difficuly I had was to change the speaker channel level using AVIA disc. I had to pause the AVIA then go to receiver's OSD setup and change speaker level.
Is there any way to change the speaker level directly without pausing the AVIA disc?
Sorry to jump in with a question in this thread.
Thanks,
Arshad

kberg

Originally posted by Dr. Spec

If you don't have that type of read out on your master volume, you will have to manually do the math in your head when you express your volume settings on playback and say for example "I was running SW-AOTC at 18 clicks (i.e., whole digit numbers) under Reference Level".

Yep, that's me.

Of course this still brings into question the matter of a master volume truly giving a 1 dB increase or decrease with every whole number change in read-out. My 3803 displays 1/2 digit increments and is very accurate, with each 1/2 digit representing a true 1/2 dB change as confirmed per my SPL meter.

Yeah, I know what you mean. Calibrating my center channel set at the receiver at "0" and increasing the master volume to show 85dB on the Rat Shack meter displays only 79 dB on my receiver!

And finally remember Reference Level is more defined by the SPL level during playback than it is the absolute volume setting. We calibrate to the same standard only to achieve parity and a benchmark, not so we can all arbitrarily set our master volumes to 00 and say with confidence we are playing back at reference level. There is no one standard for mastering the overall volume of DVDs - some are hot, some are just right, and some are cold.


Understood!

Dr. Spec

Originally posted by malikarshad
Is there any way to change the speaker level directly without pausing the AVIA disc?

Yes, use two different video inputs on your TV and simply toggle back and forth between the Avia screen and the 3803 set up screen.

I just leave the Avia tones running in manual mode, so they don't time out.

Doc

Dr. Spec

"Yeah, I know what you mean. Calibrating my center channel set at the receiver at "0" and increasing the master volume to show 85dB on the Rat Shack meter displays only 79 dB on my receiver!"

I wasn't referring to the absolute volume difference between the two. Taken out of context, your master volume setting of 79 is arbitrary and meaningless.

Taken in context, it now just so happens represents your reference level calibration benchmark.

What I was referring to is how changing your master volume from say 79 to 77 "should" equate to an exact 2 dB change in volume. But not all volume controls are created equally (so to speak) and some are better than others at representing actual changes in volume.

Doc

kberg

Thanks, Doc. Sounds like from what you said above is that although my reference level calibration benchmark is 79 on MY receiver, when I say that I am "5 clicks under reference", other folks in Polkland will know the relative playback level I would be at on THEIR calibrated system, even though the display on my receiver truly means nothing to them or me because of the varying display characteristics of ALL receivers, correct? Sorry for the wordiness.

By the way, after emailing and hearing from Tom V at SVS, I'm trying to sell my wife on the 20-39PCi, and it ain't going so well, but I'll keep ya posted. I really envy any guy who's wife gets into HT as much as the guy does - the approval process is SO much easier.

Dr. Spec

Originally posted by kberg
Thanks, Doc. Sounds like from what you said above is that although my reference level calibration benchmark is 79 on MY receiver, when I say that I am "5 clicks under reference", other folks in Polkland will know the relative playback level I would be at on THEIR calibrated system, even though the display on my receiver truly means nothing to them or me because of the varying display characteristics of ALL receivers, correct? Sorry for the wordiness.

You got it now. And its more than the differences in receiver volume displays, it also takes into account diiferences in speaker efficiency, room size, receiver power, etc.

You are correct, the display number on the volume control really means nothing taken out of context, and certainly should never be construed as an actual volume level in dB.

If you tell someone your volume is set to "79", what does that mean to them? Nothing.

If you tell someone your system is channel balanced and calibrated to Dolby Reference Level with the S&V disc test tones at 85 dB, THAT means something.

Then you can tell them you played a DVD at "X" clicks under Reference Level, and they know exactly how loud that is - if their system is also calibrated to the same standard.

RL is obviously more important for HT than it is for music. Everyone over at HTF calibrates to RL using Avia, S&V, or VE. That way we can compare notes on playback volume and how hot DVDs are mastered and what SPL peaks we hit on the bassy scenes, etc.

Bench racing high end subwoofers is a big deal to many of them, and the SPL peaks are much less meaningful without a volume benchmark. You will note in my SVS PB2+ review that I first calibrated to RL with Avia at master volume 00, then I stated how hot my sub was running (88-89), then I stated the volume setting for each DVD, then I stated the SPL peaks. That's data everyone can hang their hat on, and attempt to duplicate in their own homes if they desire.

Doc

kberg

Again, thanks much for taking the time to explain it all above. Now I feel much more educated on this topic. Hopefully, many others will benefit from this thread as well.

KB

malikarshad

Originally posted by Dr. Spec
Yes, use two different video inputs on your TV and simply toggle back and forth between the Avia screen and the 3803 set up screen.
I just leave the Avia tones running in manual mode, so they don't time out.
Doc

I have a separate video input for 3803 on my TV. The only problem is that 3803 plays its internal tones even when the AVIA test tones are playing. How do it stop that?
Thanks for your response.

Dr. Spec

Originally posted by malikarshad
I have a separate video input for 3803 on my TV. The only problem is that 3803 plays its internal tones even when the AVIA test tones are playing. How do it stop that?
Thanks for your response.

Yeah, I blew that answer, sorry. If you hit the main "enter" button on your 3803, you can scroll through the speaker levels and adjustment accordingly on the fly.

If you are processing a Dolby Digital DVD through a digital coax or a digital fiber optic, these adjustments will also be reflected in the main menu set-up speaker levels.

You can do the same for any other input (stereo, direct, pure direct, 5/7 channel, etc.) and it will save the settings for each input and these will NOT affect the main set-up levels.

It's the whole Personal Memory Denon thing - very slick.

Doc