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Discussion Starter · #1 ·
This may be a stupid question, but Im not exactly sure if Im right or not.



What I mean is. Adjusting the volume knob on my Onkyo 805 does nothing to change the volume of the speaker settings/level calibration(test tone). It is always the same volume. If I have calibrated all my speakers to 75db via the AVR's test tone. Does that mean if my volume knob is set to 0(reference) that is considered 75db? Meaning if I had a mp3 of the same pink noise that the test tone puts out. I could play it with the volume at "0" and my SPL meter would still read 75db on all my speakers?


I ask because I usually watch Blu-rays at -15 on my AVR, and its usually plenty loud. With the exception of Terminator Salvation, which is "Very" loud(during action scenes), and I, depending on my mood. Turn it down to -18 or more. I dont understand how people are watching at "0" on their AVR if calibrating to the AVR's test tone is equal to calibrating to 75db at a volume level of 0. Am I out in left field on this, or am I on the right track?
 

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No. I believe that a full-scale pink noise at 0dB on the volume will give you more like 105dB.


Playing a movie at -15dB usually gives me around 75-80dB for speech, so that would seem right.


Honestly I don't understand how 0 would be correct if that would bring normal speech to shouting levels?
It would make sense in 'large' theaters and I believe that in a smaller room close to the speakers it's giving you that 15-20dB gain (for the same power) you would not have in a large theater.
 

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You tune each speaker to 75db so the sum of all your speakers when playing at that 0 setting should equal 105db. And your sub 115db.
 

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Quote:
Originally Posted by skid_68 /forum/post/18180934


This may be a stupid question, but Im not exactly sure if Im right or not.



What I mean is. Adjusting the volume knob on my Onkyo 805 does nothing to change the volume of the speaker settings/level calibration(test tone). It is always the same volume. If I have calibrated all my speakers to 75db via the AVR's test tone. Does that mean if my volume knob is set to 0(reference) that is considered 75db? Meaning if I had a mp3 of the same pink noise that the test tone puts out. I could play it with the volume at "0" and my SPL meter would still read 75db on all my speakers?


I ask because I usually watch Blu-rays at -15 on my AVR, and its usually plenty loud. With the exception of Terminator Salvation, which is "Very" loud(during action scenes), and I, depending on my mood. Turn it down to -18 or more. I dont understand how people are watching at "0" on their AVR if calibrating to the AVR's test tone is equal to calibrating to 75db at a volume level of 0. Am I out in left field on this, or am I on the right track?




Speaker SPL output level depends on what level you use to record that pink noise. I made up a few test tone CDs in the past and when you know the record level then everything else is addition and subtraction.


The first time I made a test CD I used a -30 dB FS record level. That is also the level of the built in internal test tones of consumer receivers. When I set my master volume to the calibrated reference level (-22 dB MV on my master volume), my test tones playback at 75 dB SPL C scale.


Since my nominal listening level is about 10 dB below RL (-32 dB MV), I found that recording the test CD at a -20 dB FS level was easier to use. If I set the master volume to the calibrated reference level (-22 dB MV on my master volume), my test tones playback at 85 dB SPL C scale. Turn down the master volume by 10 dB, and the tone plays back at 75 dB SPL C scale (85 - 10).



Reference playback level is 105 dB SPL C scale assuming a 0 dB FS test signal (single channel).


The receiver's internal test tones are -30 dB FS test tones. The internal test tone playback level is 75 dB SPL (105 - 30) assuming a -30 dB FS (0 - 30) test signal with the master volume set to "reference level" (different MV numbers for different receivers).


When the CD test tones are -30 dB FS test tones, test tone playback level is 75 dB SPL (105 - 30) assuming a -30 dB FS (0 - 30) test signal with the master volume set to "reference level" (different MV numbers for different receivers).


When the CD test tones are -20 dB FS test tones, test tone playback level is 85 dB SPL (105 - 20) assuming a -20 dB FS (0 - 20) test signal with the master volume set to "reference level" (different MV numbers for different receivers).



This is just a numbers game of sorts. Movie theaters (commercial equipment) are calibrated at 85 dB SPL C scale, but they use -20 dB FS test tones. If they used -30 dB FS test tones, then the SPL calibration level would be 75 dB SPL C scale.


The bottom line is single channel levels in a movie can recorded (in theory) at up to 0 dB FS, and that gives you single channel output levels up to 105 dB SPL C scale.



Just for the record, I never playback at the full calibrated "reference level". A MV setting of 3 to 8 dB MV below the calibrated reference level is what I use. Since the calibrated reference level is -22 dB MV in with my receiver, that means my master volume is set between -25 and -30 dB MV.
 

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Discussion Starter · #5 ·
Thanks guys, it's just confusing because I see so many numbers thrown around about reference level. Like 75db is reference level, or 85db is reference level with 105db peaks.


I have another question. Does my AVR's pink noise need correction for my SPL meter(same as the RS meter)? I mean if I set my speakers to 75db via pink noise, and my sub at 80-85db with the same pink noise. Are there any correction numbers like there are with certain frequencies on the RS spl meter? Or is the db reading pretty close to what the SPL is reading using pink noise?
 

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Quote:
Originally Posted by skid_68 /forum/post/18183276


Thanks guys, it's just confusing because I see so many numbers thrown around about reference level. Like 75db is reference level, or 85db is reference level with 105db peaks.


I have another question. Does my AVR's pink noise need correction for my SPL meter(same as the RS meter)? I mean if I set my speakers to 75db via pink noise, and my sub at 80-85db with the same pink noise. Are there any correction numbers like there are with certain frequencies on the RS spl meter? Or is the db reading pretty close to what the SPL is reading using pink noise?

Since it's pink noise there isn't any way to "correct" the RS SPL meter's reading (because it's all different frequencies being played). I've read in the past that the best way to "correct" for a sub with pink noise and the RS SPL meter is to arbitrarily add 3dB to what the RS SPL meter reads and that's the actual SPL. Not very accurate but it should get you pretty close.
 

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Quote:
Originally Posted by J_Palmer_Cass /forum/post/18181444


Speaker SPL output level depends on what level you use to record that pink noise. I made up a few test tone CDs in the past and when you know the record level then everything else is addition and subtraction.


The first time I made a test CD I used a -30 dB FS record level. That is also the level of the built in internal test tones of consumer receivers. When I set my master volume to the calibrated reference level (-22 dB MV on my master volume), my test tones playback at 75 dB SPL C scale.


Since my nominal listening level is about 10 dB below RL (-32 dB MV), I found that recording the test CD at a -20 dB FS level was easier to use. If I set the master volume to the calibrated reference level (-22 dB MV on my master volume), my test tones playback at 85 dB SPL C scale. Turn down the master volume by 10 dB, and the tone plays back at 75 dB SPL C scale (85 - 10).



Reference playback level is 105 dB SPL C scale assuming a 0 dB FS test signal (single channel).


The receiver's internal test tones are -30 dB FS test tones. The internal test tone playback level is 75 dB SPL (105 - 30) assuming a -30 dB FS (0 - 30) test signal with the master volume set to "reference level" (different MV numbers for different receivers).


When the CD test tones are -30 dB FS test tones, test tone playback level is 75 dB SPL (105 - 30) assuming a -30 dB FS (0 - 30) test signal with the master volume set to "reference level" (different MV numbers for different receivers).


When the CD test tones are -20 dB FS test tones, test tone playback level is 85 dB SPL (105 - 20) assuming a -20 dB FS (0 - 20) test signal with the master volume set to "reference level" (different MV numbers for different receivers).



This is just a numbers game of sorts. Movie theaters (commercial equipment) are calibrated at 85 dB SPL C scale, but they use -20 dB FS test tones. If they used -30 dB FS test tones, then the SPL calibration level would be 75 dB SPL C scale.


The bottom line is single channel levels in a movie can recorded (in theory) at up to 0 dB FS, and that gives you single channel output levels up to 105 dB SPL C scale.



Just for the record, I never playback at the full calibrated "reference level". A MV setting of 3 to 8 dB MV below the calibrated reference level is what I use. Since the calibrated reference level is -22 dB MV in with my receiver, that means my master volume is set between -25 and -30 dB MV.

Thanks for this info, I use the dvd at the top of the DIY page to calibrate my speakers. I believe it's 95db but it says -20 down. I then calibrated my system to 85db one meter from the system, my question is though did I calibrate to 85db or 95db? Since the speakers are outputting 85db I would gather I did it to that.



I am kinda confused on the whole thing though because

1)isn't reference 105db

2)does the 105db would be for effects and 85db pink noise that is 20db down simulate dialog?
 

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Quote:
Originally Posted by lennon_68 /forum/post/18183512


Since it's pink noise there isn't any way to "correct" the RS SPL meter's reading (because it's all different frequencies being played). I've read in the past that the best way to "correct" for a sub with pink noise and the RS SPL meter is to arbitrarily add 3dB to what the RS SPL meter reads and that's the actual SPL. Not very accurate but it should get you pretty close.

+1


This is considered a "good enough" method of calibrating a sub with the Rat Shack meter, a method of which I employ myself.
 

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Quote:
Originally Posted by stgdz /forum/post/18183714


I am kinda confused on the whole thing though because

1)isn't reference 105db

2)does the 105db would be for effects and 85db pink noise that is 20db down simulate dialog?

Reference can include peaks up to 105dB. Using a -20dB relative level pink noise and calibrating to 85dB is correct. If something in the soundtrack is recorded at -20dB it will be 85dB at the listening position. If something on the soundtrack is recorded at 0dB though it will be 105dB at the listening position which is where the 105dB thrown around comes from. If your speakers are capable of playing 105dB at the listening position individually (118dB or some weird number for the sub - 115dB + possible redirected bass from all 7 channels) than your setup is capable of reference level playback. It's unnecessary (and would be unpleaseant) to use 0dB test tones to calibrate levels though!
 

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This entire discussion is moot as the basic matter of loudspeaker efficiency is not being considered at all!


I have two sets of speakers from the same manufacturer ... one pair is 78dB SPL 1W/1m while the other is 102dB SPL 1W/1m. That's a 24dB difference in SPL merely by swapping speakers!!!


Neither are you dealing with calibrated source output levels nor do all AVRs have the same gain structure.
 

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Quote:
Originally Posted by cavu /forum/post/18183909


This entire discussion is moot as the basic matter of loudspeaker efficiency is not being considered at all!


I have two sets of speakers from the same manufacturer ... one pair is 78dB SPL 1W/1m while the other is 102dB SPL 1W/1m. That's a 24dB difference in SPL merely by swapping speakers!!!


Neither are you dealing with calibrated source output levels nor do all AVRs have the same gain structure.

Isn't it all relative though? If you take a DVD of -30dB test tones, played through the DVD player you use to watch movies, connected through the same gain structure you'll use to watch movies (source output sensitivity, AVR input sensitivity, any other component sensitivities), powering the speakers you'll use (regardless of their efficiency) and calibrate them all to 75dB then you should be set. Playback of the same movie scene on two different systems that were both calibrated as described above using the same MV setting will produce the same SPL (assuming there is no compression and the rooms aren't doing anything crazy to the FR - both kinda' ridiculous assumptions but you have to assume something for there to be a standard - also the input signal obviously cannot be clipping either).


I don't see how speaker efficiency, AVR gain structure, or source output levels have anything to do with it? Maybe I'm missing something though?


J_Palmer_Cass I know you've looked into this sort of thing pretty extensively (or at least that's what I've gathered from some of your posts). What do you think?
 

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Quote:
Originally Posted by lennon_68 /forum/post/18184155


I don't see how speaker efficiency, AVR gain structure, or source output levels have anything to do with it? Maybe I'm missing something though?



You are missing nothing. CAVU is doing the usual AVS thing, adding confusion to the issue.


I don't think anyone was talking about room size, listening distance, speaker and power requirements needed to get those single speaker peak spl levels. We were only talking calibration.


As far as gain structure is concerned, all consumer equipment has a pretty fixed gain structure through the preamp level. The variations in total gain structure are speaker and power amplifier related, not preamp level related.


I have seen plenty of people on this forum (who should know better) admit to screwing up their gain structure without sdmitting that they did so. You mention it to them and they have a hissy fit. It's never the end user, it's always the equipment. Whatever!


We did not even discuss whether anyone plays back movies at full calibrated "reference level" either!
 

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Discussion Starter · #14 ·
I dont know what you guys are all talking about. I just know that my system is loud when I turn it up.
 

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Quote:
Originally Posted by skid_68 /forum/post/18180934


Adjusting the volume knob on my Onkyo 805 does nothing to change the volume of the speaker settings/level calibration(test tone). It is always the same volume. If I have calibrated all my speakers to 75db via the AVR's test tone. Does that mean if my volume knob is set to 0(reference) that is considered 75db?

Yes. AVR's generate their cal noise at -30dBFS, and that's meant to correspond to 75 dB.

Quote:
Meaning if I had a mp3 of the same pink noise that the test tone puts out. I could play it with the volume at "0" and my SPL meter would still read 75db on all my speakers?

Maybe. If the MP3 is recorded at -30 dBFS in both channels, then it should play louder than 75 dB when MV=0.

Quote:
I ask because I usually watch Blu-rays at -15 on my AVR, and its usually plenty loud. With the exception of Terminator Salvation, which is "Very" loud(during action scenes), and I, depending on my mood. Turn it down to -18 or more. I dont understand how people are watching at "0" on their AVR if calibrating to the AVR's test tone is equal to calibrating to 75db at a volume level of 0. Am I out in left field on this, or am I on the right track?

I'm with you. -15 to -20 for movies.
 

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WoW MR Dressler,

I would of pictured you as A reference "00"dB kined of Guy


when it comes to Blu-ray movie playback...


Cheers...
 

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Quote:
Originally Posted by skid_68 /forum/post/18180934


This may be a stupid question, but Im not exactly sure if Im right or not.



What I mean is. Adjusting the volume knob on my Onkyo 805 does nothing to change the volume of the speaker settings/level calibration(test tone). It is always the same volume. If I have calibrated all my speakers to 75db via the AVR's test tone. Does that mean if my volume knob is set to 0(reference) that is considered 75db? Meaning if I had a mp3 of the same pink noise that the test tone puts out. I could play it with the volume at "0" and my SPL meter would still read 75db on all my speakers?


I ask because I usually watch Blu-rays at -15 on my AVR, and its usually plenty loud. With the exception of Terminator Salvation, which is "Very" loud(during action scenes), and I, depending on my mood. Turn it down to -18 or more. I dont understand how people are watching at "0" on their AVR if calibrating to the AVR's test tone is equal to calibrating to 75db at a volume level of 0. Am I out in left field on this, or am I on the right track?

Here's a good explanation:

Quote:
Originally Posted by Big Daddy /forum/post/2505235

REFERENCE LEVEL


Reference level is defined for film mixing and movie theaters. Every studio and movie theater is calibrated according to this level. It represents an average of 85dB for the regular speakers on the SPL meter (set on C weighting and Slow) using a band limited (500Hz to 2,000Hz) pink noise at the listening position. The peak level is set 20dB higher at 105db and the LFE peak level is set +10dB higher to a maximum of 115dB. The purpose of the +10 dB gain for the LFE channel is to increase the dynamic range of bass sound such as explosions and crashes. This means when the receiver master volume is set to 0dB, the regular speakers are expected to play a peak level of 105dB and the subwoofer is expected to produce a peak output level of 115dB. This is louder than most people can tolerate, so people normally set the master volume much lower than 0 when watching movies or listening to music. Furthermore, such loud bass level places a heavy burden on the subwoofer and requires multiple high-end subwoofers to produce it accurately.


Because 85dBC test tones can be very loud in a small home theater room and can damage hearing, receiver manufacturers through the encouragement by Dolby and THX decided that a reasonable test-tone level is 75dB and that is the level that most receivers use.


To summarize,
  • Reference Level is 1.85v line level = 0dB VU meter = 85db playback level.
  • 105dB Peak level = 0dB (Full Scale).
  • 85dB Average Level = -20dB (Full Scale).
  • 75dB Average Reference Level = -30dB (Full Scale).
  • dBFS (Full Scale) = unit of measure for the amplitude of digital audio signals.
  • The reference level is "0" dBFS, which is also the maximum signal amplitude that can be stored digitally in a typical digital audio recording system.
  • Signals louder than 0dBFS just produce clipping (truncation of the waveform, hence distortion).

When calibrating your audio system, the receiver plays pink noise that is recorded at 75dB (-30dB FS). When the individual speaker levels are set to 75dB at the listening position, as measured by an SPL meter, the effects of speaker sensitivity and room acoustics are accounted for and the speakers are all level-matched against the Reference Level.


You can use either the internal test tones of a receiver or an external disc. The internal test tones of most receivers are band limited and recorded at 75dB level (-30 dB FS). External calibration signals on most discs are typically full-range pink noise and recorded at 85dB (-20dB FS). It really doesn't make a lot of difference which method you use as long as all the speakers are balanced.
http://forum.blu-ray.com/audio-theor...alization.html


I personally prefer to watch movies with a 0dB dialnorm offset at -14dB on my receiver. I tend to watch movies with a -4dB dialnorm offset at -10dB on my receiver. The two movies I have with a -6dB dialnorm offset, I listen to at -8dB on my receiver.
 

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Quote:
Originally Posted by RocShemp /forum/post/18214718


Here's a good explanation:


http://forum.blu-ray.com/audio-theor...alization.html


I personally prefer to watch movies with a 0dB dialnorm offset at -14dB on my receiver. I tend to watch movies with a -4dB dialnorm offset at -10dB on my receiver. The two movies I have with a -6dB dialnorm offset, I listen to at -8dB on my receiver.



My receiver does not have a Dialnorm Offset on the display. However, it does give you the Dialnorm value used for encoding the DVD. The -31 Dialnorm encoded DVDs should read as a Dialnorm Offset value of +4.



DD DVD Dialnorm values:


Most DVD's = -27


Air Force One = -31


WOTW = -23


Spiderman = -25 (as I recall)


Master and Commander = -27


Knight's Tale = -26


Silverado = -29


All the old James Bond DVDs = -31


The Dark Knight = -31


Batman Begins = -27
 

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Quote:
Originally Posted by Roger Dressler /forum/post/18214120



Maybe. If the MP3 is recorded at -30 dBFS in both channels, then it should play louder than 75 dB when MV=0.


Tee hee! You know that the 75 dB SPL measurement only applies to a single channel being driven. 2 channels driven will read about 81 dB SPL.




Quote:
Originally Posted by Roger Dressler /forum/post/18214120



I'm with you. -15 to -20 for movies.


What? -5 to -10 for most movies in my setup.


My old 2 channel Pioneer receiver had a mute button on it. In the old days, -20 dB was the specification for the mute button!
 

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Since my PS3 and my HD-A2 don't bitstream Dolby TrueHD or DTS-HD MA, I send all audio to my receiver as LPCM. So I never get to see the dialnorm value displayed. I have however been pretty good at estimating volume offsets by ear. No, I'm not claiming to have "golden ears". Such assertions are pure nonsense. However, the following table mirros what I've heard (except for Wolverine as I was wrong in assuming it had a -4dB dialnorm offset like that of Transformers: Revenge of the Fallen or the director's cut of Watchmen).

Quote:
Originally Posted by Big Daddy /forum/post/2505236


Please note that dialog normalization does not apply to LPCM. It is a feature that was created by Dolby Labs and added to DTS more recently.


It is also important that you remember that BD titles with zero dialnorm offset will play a bit louder. You should not conclude that the difference is because of the superiority of one codec over another.






http://forum.blu-ray.com/2505236-post2.html


Needless to say (and yet I'm saying it anyway
), I found the aforementioned table to be quite useful.
 
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