Understanding Dialog Normalization - Blu-ray Forum

Big Daddy · 11-05-2009, 01:35 PM

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. However, it is important to remember that when you play the internal test tones inside a receiver/processor, they normally bypass all post processing, including equalization.

METADATA

Metadata is the data sent along with the coded audio signal such as Dolby Digital to describe this signal to the receiver/decoder.

Metadata can contain different types of information such as the 3 Ds.:

Dialog Normalization (Level Control): This metadata sets the overall program playback level for loudness normalization (dialognorm).
Dynamic Range Control: This metadata has the ability to control the dynamic range of the decoded program by the receiver. The values are calculated in the encoder based on dynamic range profiles selected by the sound engineer. There are five standard profiles: Film Standard, Film Light, Music Standard, Music Light, and Speech.
Down-Mixing: Information on how the decoder should perform two-channel or three-channel mix from a 5.1 soundtrack. Metadata for down-mixing tells the player what the relative level of the channels should be in the fabricated Pro Logic mix. Again, this is information for your decoder's benefit, and the sound information itself is not affected by its presence.

DYNAMIC RANGE AND DYNAMIC RANGE CONTROL

Let's think of a soundtrack as a vertical bar. Dynamic Range is the difference between the quietest sound and the loudest sound. Cassette tapes can have a dynamic range of 60 dB, CD audio 80 dB, and Dolby Digital on DVD can have a dynamic range of 105 dB.

Source: Home Theater HiFi

Reducing dynamic range in simple terms means raising the level of quiet sounds and lowering the level of loud ones such that there is less of a change. By invoking dynamic range control, you will hear all of the soundtrack but not disturb others with loud peaks.

Source: Home Theater HiFi

DIALOG NORMALIZATION

The audio level between different TV programs, channels, and in particular commercials is very inconsistent. Dolby Laboratories realized that these radical differences between different types of sources, channels and content would be extremely inconvenient for a TV viewer to continually have to adjust the audio level while watching TV. Because of this, Dolby Labs decided to implement a feature called Dialog Normalization. Dolby includes this feature in metadata of any Dolby Digital bitstream. The only piece of metadata that is mandatory for consumers is dialognorm values. Other example such as downmix metadata is optional and the sound engineers can use it at their discretion.

In a soundtrack such as Dolby Digital, the loudest level is expressed as 0dB and the quietest level as -105dB. The Dialnorm value expresses the level of dialogue as how much lower it is than the peak 0dB. A value of -31 indicates 31dB below the peak. This is the value at which no volume adjustment is performed by the receiver/decoder. A Dialnorm value of -27 would indicate to the receiver/decoder that the dialogue is at a point 27dB below the peak, or 4dB higher than a program with a Dialnorm value of -31. The decoder would then turn the volume down by 4dB. A Dialnorm value of -25 would call for a 6dB reduction and so on. The -27dB setting yields a very natural level for talking and has been the standard level for dialogue in motion picture soundtracks.

Dialogue Normalization works by assigning a relative numerical value as described above to the average dialogue level of a given program, commercial, movie etc. This numerical value should be calculated using hardware or software tools offered by Dolby and is then encoded into the Metadata by the content creator or broadcaster. The graph below shows some of the typical relative levels between different types of source material. The black line and the numerical number next to that line, would be the dialog normalization level.

Source: TVTechnology.com

This numerical value is used by the receiver/decoder to automatically adjust the level of the audio, so that during playback all these different types of program material have the same average dialog level. The graph below shows the resulting adjusted level.

Source: TVTechnology.com

Dialog Normalization does not affect the original audio signals that are fed into the encoder such as the level or the dynamics of the program. The receiver/decoder reads the dialnorm value in the metadata and adjusts the level of audio programs so that the dialog is at a consistent and uniform level. It is important to note that decoders are required to make use of this metadata parameter and apply the proper normalization/attenuation based on the transmitted dialnorm value to the decoded audio program.

SUMMARY AND IMPORTANT FACTS

Dialog Normalization is not the same thing as Dynamic Range Control (DRC).
Dialog Normalization does not reduce dynamic range.
Dynamic Range Control is the same as Night Mode.
Dialog Normalization does not affect the level of dialogue with respect to the other channels or content.
Dialog Normalization does not adversely affect the signal-to-noise (S/N) ratio.
The default settings for Dolby encoders is -27dBFS.
The default dialog setting for DTS is -31dBFS.
DTS soundtracks, unlike Dolby Digital, are not attenuated by 4 dB by the receiver/decoder and as a result DTS movies play 4dB louder than Dolby Digital movies.
It should be noted that most THX-certified receivers and processors attenuate DTS movies by 4dB.
If you want your receiver/processor to report the dialnorm values, you must set the player's audio output to bitstream. In the Denon receivers, this value is reported in the menu under Information, Audio Input Signal. For other receivers, please check the manual or the internal menu of the receiver.

DIGITAL VOLUME ATTENUATION

Although the metadata contains different types of information, the only one that is mandatory and must be used is Dialog Normalization. It is important to remember that there are many movies that do not use DN. The dialog normalization vlaues can be between zero (no attenuation) to -31 (31 dB attenuation). The most common value for the dialog normalization is -4 dB.

The attenuation due to Dialog Normalization is performed in the digital domain before the D/A conversion. The PCM output that is outputted from the player is transcoded after the values in the metadata are applied. When DTS-HD MA and Dolby TrueHD are transcoded to PCM, all metadata (DN, etc.) is then stripped away from the encoded PCM stream. This happens because uncompressed LPCM cannot carry a secondary stream like metadata, and this is the reason why receivers do not show any DN offset.

Digital attenuation takes place by multiplying each successive word in the input data stream by a coefficient that is less than one. For example, if the incoming stream is multiplied by a coefficient of 0.5, the output will be reduced by half. This is equivalent to a volume reduction of 6 dB. In a binary system, a reduction of 6 dBs is represented as shifting the signal from the most significant bit towards the least-significant bit by one bit. This will result in a reduced resolution by one bit. This is illustrated in the following diagram:

All Diagrams are created by Big Daddy

Using the same analysis, if the incoming signal is attenuated by a factor of eight, this will result in a volume reduction of 18 dB and the resolution will be lost by 3 bits.

Now, let’s apply the above analysis to a practical 16 bit audio from a blu-ray movie. In practice, 24-bit or 32-bit processors and digital/analog converters are used. As a result, a 16-bit signal from a BD can be attenuated without loss of the original 16-bit information.

Similarly, you can find an example of 24-bit digital volume control attenuation in the following. Let’s assume a 16-bit input from a BD or DVD fed into it. The 24-bit DSP performs digital filtering and resolution enhancement, producing a 24-bit signal. The additional bits are represented by the dotted lines being fed to at the eight least-significant bits of the 24-bit DAC. Let’s assume the original 16-bit audio input is attenuated by 18 dB. This results in the loss of the three least significant bits, but the original 16-bit information from the BD/DVD is preserved.

Even if the 16-bit signal is attenuated by 30 dB, as shown below, there will be a reduction of five bits, but the original 16-bit signal is preserved intact.

The Oppo BDP-95 and BDP-105 players use 32 bit processing. The digital volume controller on these units affects only the analog signals coming out of the player. I have seen concerns expressed by quite a few people over the loss of resolution if the digital volume attenuation is used. Let me assure you that this concern is completely unwarranted. If a 24 bit signal is fed into a 32 bit processor, the digital volume controller can be attenuated up to 48 dBs (8 bits) without any loss of resolution. If the input signal is from a CD (16 bits), the volume can be attenuated up to 96 dBs (16 bits) without any loss of resolution.

Strictly speaking, digital attenuation does reduce resolution. However, analog volume controls and associated circuitry have many negative side effects such a loss of resolution caused by analog circuitry and connectors in the signal path. The degradation and noise of the analog circuitry are present under all conditions, regardless of playback volume level.

REFERENCES

Big Daddy · 11-05-2009, 01:36 PM

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.

Fors* · 11-05-2009, 01:46 PM

Another great sticky Big Daddy! Thank you for this information, especially in light of the conversation we had on it yesterday! I understand this much better now.

Big Daddy · 11-05-2009, 02:10 PM

Quote:

Originally Posted by forsberg21

Another great sticky Big Daddy! Thank you for this information, especially in light of the conversation we had on it yesterday! I understand this much better now.

Too many people confuse Dialog Normalization with Dynamic Range Control and wrongly assume that dialnorm affects the quality of audio.

Fors* · 11-05-2009, 02:23 PM

Quote:

Originally Posted by Big Daddy

Too many people confuse Dialog Normalization with Dynamic Range Control and wrongly assume that dialnorm affects the quality of audio.

That was something that I was trying to figure out yesterday. On the surface it seems like it would, but with your explanation, I have a better grasp on how and why it is implemented. It is nice to know that there is nothing to be afraid of with Dialog Normalization.

Your sticky's are always simple to understand and informative BD!

Big Daddy · 11-05-2009, 02:32 PM

Quote:

Originally Posted by forsberg21

That was something that I was trying to figure out yesterday. On the surface it seems like it would, but with your explanation, I have a better grasp on how and why it is implemented. It is nice to know that there is nothing to be afraid of with Dialog Normalization.

Your sticky's are always simple to understand and informative BD!

Thank you.

I try to make things as easy as possible so that people with limited scientific knowledge can understand the topic. I hope I have succeeded this time. I will modify and add to the op, but I didn't get much sleep last night and I need to dialnorm myself.

Fors* · 11-05-2009, 02:50 PM

Quote:

Originally Posted by Big Daddy

Thank you.

I try to make things as easy as possible so that people with limited scientific knowledge can understand the topic. I hope I have succeeded this time. I will modify and add to the op, but I didn't get much sleep last night and I need to dialnorm myself.

If you figure out how to turn off dialnorm with your significant other, please let me know!

Big Daddy · 11-05-2009, 02:58 PM

Quote:

Originally Posted by forsberg21

If you figure out how to turn off dialnorm with your significant other, please let me know!

This is the most effective technique to use dialog normalization on your significant other.

cembros · 11-05-2009, 03:13 PM

WOW well done sir. I tried to do something similar in a post about a week ago and acheived an epic fail. This is probably the most important of all your stickeys, to many people are confused about dialnorm and do not fully enjoy some really great tracks because of that. I would love to add a point about Indiana Jones, this seems to be the only track with a dialnorm value of -25, this means it is played 2-6db quiter than other tracks. I for the longest time did not realize this and found the track to be lacking. Reading reviews of the audio on the movie it seems the revewers experienced the samething. Once I played the movie at +2db on my receiver the track really rocked, a 5 star track without a doubt. I highly recomend that anyone with this movie (forget if you like the movie or not) go back and revisit it at the correct volume level.

Steve · 11-05-2009, 03:36 PM

Thanks for the great sticky Big Daddy. With all I've been seeing mentioned and discussed about this topic over the last few days, it's something I've been wanting to learn more about when I had the time. I have a much better grasp on it now.

Hammie · 11-05-2009, 03:47 PM

Quote:

Originally Posted by cembros

WOW well done sir. I tried to do something similar in a post about a week ago and acheived an epic fail. This is probably the most important of all your stickeys, to many people are confused about dialnorm and do not fully enjoy some really great tracks because of that. I would love to add a point about Indiana Jones, this seems to be the only track with a dialnorm value of -25, this means it is played 2-6db quiter than other tracks. I for the longest time did not realize this and found the track to be lacking. Reading reviews of the audio on the movie it seems the revewers experienced the samething. Once I played the movie at +2db on my receiver the track really rocked, a 5 star track without a doubt. I highly recomend that anyone with this movie (forget if you like the movie or not) go back and revisit it at the correct volume level.

The new G.I. Joe also appears to be offset by 6db.

Steve · 11-05-2009, 06:31 PM

I have a question regarding implementation. Is this something that receivers do automatically, or is it a feature that has to be turned on or off? How do you go about putting it into use exactly?

jomari · 11-05-2009, 08:16 PM

what the hell man! now what in the world should i write about to make a sticky?

home theater drapes?
popcorn recipes?
the effects of iodized salt to room acoustics and the axial mode?

great postin...

just a heads up, in relation to the posting... Crackinhedz posted a great article related to the said topic...

https://forum.blu-ray.com/showpost.p...90&postcount=5

Hammie · 11-05-2009, 10:24 PM

Quote:

Originally Posted by jomari

what the hell man! now what in the world should i write about to make a sticky?

home theater drapes?
popcorn recipes?
the effects of iodized salt to room acoustics and the axial mode?

great postin...

just a heads up, in relation to the posting... Crackinhedz posted a great article related to the said topic...

https://forum.blu-ray.com/showpost.p...90&postcount=5

That's actually from the same article BD used as a reference for his -- the Hometheaterhifi website.

Irrob · 11-05-2009, 10:38 PM

Big Daddy comes through yet again with a fantastic sticky. Thank you sir.

Big Daddy · 11-05-2009, 11:35 PM

Quote:

Originally Posted by cembros

WOW well done sir. I tried to do something similar in a post about a week ago and acheived an epic fail. This is probably the most important of all your stickeys, to many people are confused about dialnorm and do not fully enjoy some really great tracks because of that. I would love to add a point about Indiana Jones, this seems to be the only track with a dialnorm value of -25, this means it is played 2-6db quiter than other tracks. I for the longest time did not realize this and found the track to be lacking. Reading reviews of the audio on the movie it seems the revewers experienced the samething. Once I played the movie at +2db on my receiver the track really rocked, a 5 star track without a doubt. I highly recomend that anyone with this movie (forget if you like the movie or not) go back and revisit it at the correct volume level.

Quote:

Originally Posted by Irrob

Big Daddy comes through yet again with a fantastic sticky. Thank you sir.

Thank you for the compliments. Dialnorm is probably the most misunderstood topic in audio.

Big Daddy · 11-05-2009, 11:38 PM

Quote:

Originally Posted by fireman325

I have a question regarding implementation. Is this something that receivers do automatically, or is it a feature that has to be turned on or off? How do you go about putting it into use exactly?

Receivers/decoders are required to read the dialnorm information in the metadata and use it. The only thing you can do is get a nice remote control and adjust the volume according to your taste. Don't forget about the neighbors.

Steve · 11-05-2009, 11:46 PM

Quote:

Originally Posted by Big Daddy

Receivers/decoders are required to read the dialnorm information in the metadata and use it. The only thing you can do is get a nice remote control and adjust the volume according to your taste. Don't forget about the neighbors.

I have a Harmony One, and I'm not in an apartment.

As usual, thanks for the helpful response.

Big Daddy · 11-06-2009, 03:59 AM

Please check the new table in Post #2 and help me add to the list. Thank you.

talstarone · 11-06-2009, 05:26 AM

Big Daddy,My Friend,You Have Another Winner in this Thread

.

I Love how informative it is.And the ease in which you are able to explain so many things that even I can understand.

I must get a SPL Meter now.No More Excuses in Putting it off.The Chart/List you have started of different movies and their levels is fascinating.I will do my part in adding any titles and infotmation about the Levels these Movies Default to when Playing.
As I have noticed some movies have to be played Louder(and some even at Lower Levels to match the output of another Movie).

Thanks for the PM and Including me in this,Big Daddy. And I watched your ex-projector again earlier today on Ice Age 3. Simply Breath Taking.I Love that Sony Projector with a passion.I cant wait to get the screen early next week.

But count me in BD.I will do all I can to Contribute to the Movie Volume Reference Level.
I Hope you are Enjoying a Wonderful Evening,my Friend

.

11-05-2009, 01:35 PM	#1
Big Daddy Blu-ray Champion Member since:Jan 2008 Location:Southern California Home Theater Gallery:79 Blu-ray collection:122 Trading Score:1	Understanding Dialog Normalization 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. However, it is important to remember that when you play the internal test tones inside a receiver/processor, they normally bypass all post processing, including equalization. METADATA Metadata is the data sent along with the coded audio signal such as Dolby Digital to describe this signal to the receiver/decoder. Metadata can contain different types of information such as the 3 Ds.: Dialog Normalization (Level Control): This metadata sets the overall program playback level for loudness normalization (dialognorm). Dynamic Range Control: This metadata has the ability to control the dynamic range of the decoded program by the receiver. The values are calculated in the encoder based on dynamic range profiles selected by the sound engineer. There are five standard profiles: Film Standard, Film Light, Music Standard, Music Light, and Speech. Down-Mixing: Information on how the decoder should perform two-channel or three-channel mix from a 5.1 soundtrack. Metadata for down-mixing tells the player what the relative level of the channels should be in the fabricated Pro Logic mix. Again, this is information for your decoder's benefit, and the sound information itself is not affected by its presence. DYNAMIC RANGE AND DYNAMIC RANGE CONTROL Let's think of a soundtrack as a vertical bar. Dynamic Range is the difference between the quietest sound and the loudest sound. Cassette tapes can have a dynamic range of 60 dB, CD audio 80 dB, and Dolby Digital on DVD can have a dynamic range of 105 dB. Source: Home Theater HiFi Reducing dynamic range in simple terms means raising the level of quiet sounds and lowering the level of loud ones such that there is less of a change. By invoking dynamic range control, you will hear all of the soundtrack but not disturb others with loud peaks. Source: Home Theater HiFi DIALOG NORMALIZATION The audio level between different TV programs, channels, and in particular commercials is very inconsistent. Dolby Laboratories realized that these radical differences between different types of sources, channels and content would be extremely inconvenient for a TV viewer to continually have to adjust the audio level while watching TV. Because of this, Dolby Labs decided to implement a feature called Dialog Normalization. Dolby includes this feature in metadata of any Dolby Digital bitstream. The only piece of metadata that is mandatory for consumers is dialognorm values. Other example such as downmix metadata is optional and the sound engineers can use it at their discretion. In a soundtrack such as Dolby Digital, the loudest level is expressed as 0dB and the quietest level as -105dB. The Dialnorm value expresses the level of dialogue as how much lower it is than the peak 0dB. A value of -31 indicates 31dB below the peak. This is the value at which no volume adjustment is performed by the receiver/decoder. A Dialnorm value of -27 would indicate to the receiver/decoder that the dialogue is at a point 27dB below the peak, or 4dB higher than a program with a Dialnorm value of -31. The decoder would then turn the volume down by 4dB. A Dialnorm value of -25 would call for a 6dB reduction and so on. The -27dB setting yields a very natural level for talking and has been the standard level for dialogue in motion picture soundtracks. Dialogue Normalization works by assigning a relative numerical value as described above to the average dialogue level of a given program, commercial, movie etc. This numerical value should be calculated using hardware or software tools offered by Dolby and is then encoded into the Metadata by the content creator or broadcaster. The graph below shows some of the typical relative levels between different types of source material. The black line and the numerical number next to that line, would be the dialog normalization level. Source: TVTechnology.com This numerical value is used by the receiver/decoder to automatically adjust the level of the audio, so that during playback all these different types of program material have the same average dialog level. The graph below shows the resulting adjusted level. Source: TVTechnology.com Dialog Normalization does not affect the original audio signals that are fed into the encoder such as the level or the dynamics of the program. The receiver/decoder reads the dialnorm value in the metadata and adjusts the level of audio programs so that the dialog is at a consistent and uniform level. It is important to note that decoders are required to make use of this metadata parameter and apply the proper normalization/attenuation based on the transmitted dialnorm value to the decoded audio program. SUMMARY AND IMPORTANT FACTS Dialog Normalization is not the same thing as Dynamic Range Control (DRC). Dialog Normalization does not reduce dynamic range. Dynamic Range Control is the same as Night Mode. Dialog Normalization does not affect the level of dialogue with respect to the other channels or content. Dialog Normalization does not adversely affect the signal-to-noise (S/N) ratio. The default settings for Dolby encoders is -27dBFS. The default dialog setting for DTS is -31dBFS. DTS soundtracks, unlike Dolby Digital, are not attenuated by 4 dB by the receiver/decoder and as a result DTS movies play 4dB louder than Dolby Digital movies. It should be noted that most THX-certified receivers and processors attenuate DTS movies by 4dB. If you want your receiver/processor to report the dialnorm values, you must set the player's audio output to bitstream. In the Denon receivers, this value is reported in the menu under Information, Audio Input Signal. For other receivers, please check the manual or the internal menu of the receiver. DIGITAL VOLUME ATTENUATION Although the metadata contains different types of information, the only one that is mandatory and must be used is Dialog Normalization. It is important to remember that there are many movies that do not use DN. The dialog normalization vlaues can be between zero (no attenuation) to -31 (31 dB attenuation). The most common value for the dialog normalization is -4 dB. The attenuation due to Dialog Normalization is performed in the digital domain before the D/A conversion. The PCM output that is outputted from the player is transcoded after the values in the metadata are applied. When DTS-HD MA and Dolby TrueHD are transcoded to PCM, all metadata (DN, etc.) is then stripped away from the encoded PCM stream. This happens because uncompressed LPCM cannot carry a secondary stream like metadata, and this is the reason why receivers do not show any DN offset. Digital attenuation takes place by multiplying each successive word in the input data stream by a coefficient that is less than one. For example, if the incoming stream is multiplied by a coefficient of 0.5, the output will be reduced by half. This is equivalent to a volume reduction of 6 dB. In a binary system, a reduction of 6 dBs is represented as shifting the signal from the most significant bit towards the least-significant bit by one bit. This will result in a reduced resolution by one bit. This is illustrated in the following diagram: All Diagrams are created by Big Daddy Using the same analysis, if the incoming signal is attenuated by a factor of eight, this will result in a volume reduction of 18 dB and the resolution will be lost by 3 bits. Now, let’s apply the above analysis to a practical 16 bit audio from a blu-ray movie. In practice, 24-bit or 32-bit processors and digital/analog converters are used. As a result, a 16-bit signal from a BD can be attenuated without loss of the original 16-bit information. Similarly, you can find an example of 24-bit digital volume control attenuation in the following. Let’s assume a 16-bit input from a BD or DVD fed into it. The 24-bit DSP performs digital filtering and resolution enhancement, producing a 24-bit signal. The additional bits are represented by the dotted lines being fed to at the eight least-significant bits of the 24-bit DAC. Let’s assume the original 16-bit audio input is attenuated by 18 dB. This results in the loss of the three least significant bits, but the original 16-bit information from the BD/DVD is preserved. Even if the 16-bit signal is attenuated by 30 dB, as shown below, there will be a reduction of five bits, but the original 16-bit signal is preserved intact. The Oppo BDP-95 and BDP-105 players use 32 bit processing. The digital volume controller on these units affects only the analog signals coming out of the player. I have seen concerns expressed by quite a few people over the loss of resolution if the digital volume attenuation is used. Let me assure you that this concern is completely unwarranted. If a 24 bit signal is fed into a 32 bit processor, the digital volume controller can be attenuated up to 48 dBs (8 bits) without any loss of resolution. If the input signal is from a CD (16 bits), the volume can be attenuated up to 96 dBs (16 bits) without any loss of resolution. Strictly speaking, digital attenuation does reduce resolution. However, analog volume controls and associated circuitry have many negative side effects such a loss of resolution caused by analog circuitry and connectors in the signal path. The degradation and noise of the analog circuitry are present under all conditions, regardless of playback volume level. REFERENCES http://www.dolby.com/uploadedFiles/z...r_NCTA2001.pdf http://www.dolby.com/uploadedFiles/A...data.Guide.pdf http://www.dolby.com/uploadedFiles/A...llMetadata.pdf http://www.dolby.com/uploadedFiles/A...mple_Dolby.pdf http://www.dolby.com/uploadedFiles/z...StartGuide.pdf http://www.dolby.com/professional/te...-metadata.html http://www.dolby.com/professional/te...t/dolby-e.html http://www.dolby.com/uploadedFiles/z...tandards.P.pdf Dialogue Normalization: Friend or Foe Why are TV commercials so loud? : Audio Design Labs Inc. TVTechnology.com Managing DTV LOUDNESS with dialnorm nodef Home Theater: 0 dB THX reference level http://www.highdefdigest.com/news/show/1233 http://www.highdefdigest.com/news/sh...D_Advisor/3509 http://www.tvtechnology.com/article/12648 http://www.videor.com/imguser/Redakt...paper_axon.pdf https://secure.connect.pbs.org/confe...perSession.pdf http://www.minnetonkaaudio.com/produ...lbyefaq.html#8 Last edited by Big Daddy; 02-19-2013 at 12:37 AM.

11-05-2009, 06:31 PM	#12
Steve Blu-ray Knight Top contributor Member since:May 2008 Location:Jacksonville, FL Home Theater Gallery:54 Blu-ray collection:319 Trading Score:41	I have a question regarding implementation. Is this something that receivers do automatically, or is it a feature that has to be turned on or off? How do you go about putting it into use exactly? Last edited by Steve; 11-05-2009 at 10:30 PM.

11-05-2009, 08:16 PM	#13
jomari Moderator Top contributor Member since:Nov 2007 Home Theater Gallery:18 Blu-ray reviews:2 Trading Score:2	what the hell man! now what in the world should i write about to make a sticky? home theater drapes? popcorn recipes? the effects of iodized salt to room acoustics and the axial mode? great postin... just a heads up, in relation to the posting... Crackinhedz posted a great article related to the said topic... https://forum.blu-ray.com/showpost.p...90&postcount=5 Last edited by jomari; 11-05-2009 at 08:21 PM.

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11-05-2009, 01:36 PM	#2
Big Daddy Blu-ray Champion Member since:Jan 2008 Location:Southern California Home Theater Gallery:79 Blu-ray collection:122 Trading Score:1	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. Last edited by Big Daddy; 01-22-2013 at 07:28 PM.

11-05-2009, 01:46 PM	#3
Fors* Moderator Top ranked HT gallery Top contributor Member since:Jan 2009 Location:Positioning myself in front of the crease, getting slashed behind the knees by Billy Smith! :( Home Theater Gallery:145 Blu-ray collection:130 Trading Score:11	Another great sticky Big Daddy! Thank you for this information, especially in light of the conversation we had on it yesterday! I understand this much better now.

11-05-2009, 03:13 PM	#9
cembros Power Member Member since:Jan 2008 Blu-ray collection:456 Trading Score:4	WOW well done sir. I tried to do something similar in a post about a week ago and acheived an epic fail. This is probably the most important of all your stickeys, to many people are confused about dialnorm and do not fully enjoy some really great tracks because of that. I would love to add a point about Indiana Jones, this seems to be the only track with a dialnorm value of -25, this means it is played 2-6db quiter than other tracks. I for the longest time did not realize this and found the track to be lacking. Reading reviews of the audio on the movie it seems the revewers experienced the samething. Once I played the movie at +2db on my receiver the track really rocked, a 5 star track without a doubt. I highly recomend that anyone with this movie (forget if you like the movie or not) go back and revisit it at the correct volume level.

11-05-2009, 03:36 PM	#10
Steve Blu-ray Knight Top contributor Member since:May 2008 Location:Jacksonville, FL Home Theater Gallery:54 Blu-ray collection:319 Trading Score:41	Thanks for the great sticky Big Daddy. With all I've been seeing mentioned and discussed about this topic over the last few days, it's something I've been wanting to learn more about when I had the time. I have a much better grasp on it now.

11-05-2009, 10:38 PM	#15
Irrob Blu-ray Guru Top ranked HT gallery Top contributor Member since:Aug 2007 Location:USA Home Theater Gallery:49 Blu-ray collection:837 DVD collection:16 Blu-ray reviews: 4 Trading Score:68	Big Daddy comes through yet again with a fantastic sticky. Thank you sir.

11-06-2009, 03:59 AM	#19
Big Daddy Blu-ray Champion Member since:Jan 2008 Location:Southern California Home Theater Gallery:79 Blu-ray collection:122 Trading Score:1	Please check the new table in Post #2 and help me add to the list. Thank you.

11-06-2009, 05:26 AM	#20
talstarone Blu-ray Baron Top contributor Member since:Apr 2009 Location:Clayton, North Carolina Home Theater Gallery:88 Blu-ray collection:363 Blu-ray reviews: 3 Trading Score:54	Big Daddy,My Friend,You Have Another Winner in this Thread . I Love how informative it is.And the ease in which you are able to explain so many things that even I can understand. I must get a SPL Meter now.No More Excuses in Putting it off.The Chart/List you have started of different movies and their levels is fascinating.I will do my part in adding any titles and infotmation about the Levels these Movies Default to when Playing. As I have noticed some movies have to be played Louder(and some even at Lower Levels to match the output of another Movie). Thanks for the PM and Including me in this,Big Daddy. And I watched your ex-projector again earlier today on Ice Age 3. Simply Breath Taking.I Love that Sony Projector with a passion.I cant wait to get the screen early next week. But count me in BD.I will do all I can to Contribute to the Movie Volume Reference Level. I Hope you are Enjoying a Wonderful Evening,my Friend .