Does 0db signify anything in particular?

I have a 90Wx7 receiver. I am wondering how many watts is it outputting @0db. The volume goes from -80db to +?. It's pretty loud @ -10db, and I watch movies at -15db usually. I've had it down to +10db, but I'm afraid to go any lower in that it might damage my cheap speakers.

Thanks,
-SteveO..

0db is reference level for movie audio if you have calibrated your audio system properly.

I am wondering how many watts is it outputting @0db.

Impossible to know without measuring it. And obviously it varies depending on what you're playing, what your speakers are, etc. etc. etc. It isn't really a meaningful question.

0db means it isnt taking away from the signal coming in in order tyo make it quieter, and it isnt adding volume to the signal to make it louder.

I play xbox at -16db usually, movies range all over the place depending on the source, and I watch TV anywhere from -6 to 0db depending on the channel. CBS is always so much louder than the other channels...

0db is reference level for movie audio if you have calibrated your audio system properly..............if that is how that particular AVR works.

.............if that is how that particular AVR works.

:confused:

What would how it works have any bearing on it? If you calibrate 0db to reference level, then 0db is reference level. If for some reason the volume readout is wrong and the scaling to other dbs away from reference are not accurately reflected by the db readout, it would still be correct a 0db since that's the point you calibrated.

But I've never encountered a receiver whose dB readouts were wrong. Not saying there aren't any out there, I've just never heard of this being an issue.

.............if that is how that particular AVR works.
He did say, "...if you have calibrated your audio system properly." I don't know of any receivers that use the negative numbers increasing to "0" arrangement that *don't* use "0" as Reference Level in a properly calibrated system. Do you?

"0db means it isnt taking away from the signal coming in in order to make it quieter, and it isnt adding volume to the signal to make it louder."

"0db is reference level for movie audio if you have calibrated your audio system properly."

OK I've read that "reference level" is what the director intends for the audience to experience.

If I am interpreting these statements correctly then it sounds like true 0db is the optimal listening volume?

Thanks Again,
-SteveO..

"0db means it isnt taking away from the signal coming in in order to make it quieter, and it isnt adding volume to the signal to make it louder."

"0db is reference level for movie audio if you have calibrated your audio system properly."

OK I've read that "reference level" is what the director intends for the audience to experience.

If I am interpreting these statements correctly then it sounds like true 0db is the optimal listening volume?

Thanks Again,
-SteveO..

Sure. Go ahead and try it.

If your system is calibrated such that "0 dB" is set to reference level, that means your system is capable of playing back movies at an average sound pressure level (SPL) of 85 dB (loud), with peak SPLs of 105 dB (LOUD) and 115 dB SPL (LOUD) from the subwoofer. Having seen the pictures of your system, I can almost guarantee that those levels will shred your speakers and shatter your porcelin throne.

Sure. Go ahead and try it.

If your system is calibrated such that "0 dB" is set to reference level, that means your system is capable of playing back movies at an average sound pressure level (SPL) of 85 dB (loud), with peak SPLs of 105 dB (LOUD) and 115 dB SPL (LOUD) from the subwoofer. Having seen the pictures of your system, I can almost guarantee that those levels will shred your speakers and shatter your porcelin throne.

You really lost me there bluesky. I am not asking about my system in particular in the 2nd post. Sorry for the lack of clarity.

Let me re-phrase the question:
If an AVR was properly calibrated @ 0db, would that be the volume the director intended for the movie to be heard?

-Stv..

I have a better understanding now. I finally found a good website. Interesting read really:

NODEF (http://nodef.blogspot.com/2008/11/0-db-thx-reference-level.html)

Funny excerpt:

"The 0 dB THX reference level is part of this quality assurance and the volume control knob is usually behind a locked panel so that it cannot be adjusted. This ensures that all movies played in a THX certified theater are played at the correct THX 0 dB reference level. Unfortunately a 0 dB volume level is too loud for many patrons and cinema owners so over time many certified THX theaters will have their "locked" reference volume levels reduced. If the rules aren't enforced then what use are rules?"


-Stv..

You really lost me there bluesky. I am not asking about my system in particular in the 2nd post. Sorry for the lack of clarity.

Let me re-phrase the question:
If an AVR was properly calibrated @ 0db, would that be the volume the director intended for the movie to be heard?

-Stv..

Yes. That is the intended playback volume.

However that doesn't mean you should play it back in your space, on your system, which is VASTLY different than a larger commercial theater in many ways. Relatively few dedicated systems have the acoustical design and capabilities to playback cleanly at reference level. And of course there is the consideration of long-term listening on your hearing.

:confused:

What would how it works have any bearing on it? If you calibrate 0db to reference level, then 0db is reference level. If for some reason the volume readout is wrong and the scaling to other dbs away from reference are not accurately reflected by the db readout, it would still be correct a 0db since that's the point you calibrated.

But I've never encountered a receiver whose dB readouts were wrong. Not saying there aren't any out there, I've just never heard of this being an issue.



The big if. If my aunt had a beard would she be my uncle?

Like Silvy said, 0dB means different things on different receivers. THX uses one scheme. Other non THX units use many different schemes.

0 dB on my receiver means the master volume is all the way up. It is impossible to calibrate 0 dB as "Reference Level" with my receiver (non THX). Upon calibration, "Reference Level" ends up at about -22 dB on my receiver's display.

I have a better understanding now. I finally found a good website. Interesting read really:

NODEF (http://nodef.blogspot.com/2008/11/0-db-thx-reference-level.html)

Funny excerpt:

"The 0 dB THX reference level is part of this quality assurance and the volume control knob is usually behind a locked panel so that it cannot be adjusted. This ensures that all movies played in a THX certified theater are played at the correct THX 0 dB reference level. Unfortunately a 0 dB volume level is too loud for many patrons and cinema owners so over time many certified THX theaters will have their "locked" reference volume levels reduced. If the rules aren't enforced then what use are rules?"


-Stv..


THX "Reference Level" requires THX equipment!!!

Following is the best (and easy to understand) description of Reference Level that I have seen and it was written by our Audyssey friend Chris Kyriakakis:

http://www.avsforum.com/avs-vb/showpost.php?p=16308139&postcount=14102

One catch that is often mentioned by Chris, and many others, is that movies are mixed at Reference Level; not most other materials (concerts, CDs, etc.). This can cause big jumps in volume level settings when you watch (or listen) to these vs. movies.

THX "Reference Level" requires THX equipment!!!

Ummm, no it doesn't. There is a lot of non-THX gear out there that is fully capable of reaching peaks of 105 dB SPL on the mains and 115 db SPL from the subs.

THX "Reference Level" requires THX equipment!!!
Ummm, no it doesn't. There is a lot of non-THX gear out there that is fully capable of reaching peaks of 105 dB SPL on the mains and 115 db SPL from the subs.I think he was referring to the THX 0dB reference. With a system fully consisting of THX components and speakers (and this is a necessity), the 0-dB setting on the receiver will get 105 dB SPL in the room, IIR. This is why THX receivers have settings that go above 0 (+4, +6 dB, etc.), as you can push the system above the reference level.

With other, non-THX receivers, the dB readout on the volume control has nothing to do with an in-room sound pressure level. The numbers, IIR, refer to the signal level (voltage) of the pre amp section . 0 dB is maximum gain (or as J Palmer Cass put it, “all the way up” :D ), and negative readings below that point indicate how much the signal is attenuated (again, voltage, not SPL).

Receivers that aren’t THX but use (+) settings on the volume control, I have no idea what their reference is.

Regards,
Wayne A. Pflughaupt

Ummm, no it doesn't. There is a lot of non-THX gear out there that is fully capable of reaching peaks of 105 dB SPL on the mains and 115 db SPL from the subs.


The master volume control determines SPL levels. Given the proper speakers and the proper power, you can playback well above "Reference Level". That is not the issue.


THX Reference Level is different than Dolby Reference Level.


Dolby Reference Level calibration assumes that a dialnorm value of -31 is used in the DD encoding process. This also equates to DTS Reference Level.

THX Reference Level calibration assumes that a dialnorm value of -27 is used in the DD encoding process. Most DD DVD's use a dialnorm value of -27, but there are many exceptions to this.


What the above means is that calibrated THX Reference Level equipment plays back at 4 dB higher in level than calibrated Dolby Reference Level equipment if the same DD DVD is used as source material.


In addition if your BM is setup for all small speakers, your subwoofer needs to have the capability to output up to 121 dB SPL for LFE & RB when played back at reference level under the calibration conditions listed above.

The master volume control determines SPL levels. Given the proper speakers and the proper power, you can playback well above "Reference Level". That is not the issue.


THX Reference Level is different than Dolby Reference Level.


Dolby Reference Level calibration assumes that a dialnorm value of -31 is used in the DD encoding process. This also equates to DTS Reference Level.

THX Reference Level calibration assumes that a dialnorm value of -27 is used in the DD encoding process. Most DD DVD's use a dialnorm value of -27, but there are many exceptions to this.


What the above means is that calibrated THX Reference Level equipment plays back at 4 dB higher in level than calibrated Dolby Reference Level equipment if the same DD DVD is used as source material.


In addition if your BM is setup for all small speakers, your subwoofer needs to have the capability to output up to 121 dB SPL for LFE & RB when played back at reference level under the calibration conditions listed above.

I don't see what dialnorm has to do with this. Reference levels are absolute SPLs: 85 dB SPL average, 105 dB SPL peak for main speakers, 115 dB SPL for the LFE channel, and yes, 121 dB SPL for the subwoofer combination of LFE and redirected bass. According to every discussion I have read, these are the values defined as the motion picture audio re-recording standards. I have never seen dialnorm factored into any such discussion on reference levels, and there have been plenty of them on this forum. Please provide links to any information that relates dialnorm to reference level and I will be happy to review it and change my views if they are incorrect.

Receivers that aren’t THX but use (+) settings on the volume control, I have no idea what their reference is.

That is for increasing the signal level.

Just to add ....my receiver goes up to +10 or so, but even with adjusting individual levels I cannot get reference to 0...it is always in the -6 range tops, because my amp and speakers are so sensitive that -6 is the highest the pre-amp can go to achieve reference level even with the individual channel trims down to -10.

Ya, I had always thought that 0db means it isn't adding or taking away from the signal level, just like 0 on a sound board. I had no idea that 0 was supposed to be some specific SPL in the system. That doesn't really make sense to me since different sources hae different signal levels from them that all produce different volume at any given db setting on the receiver. And all speakers have different sensitivity so turning up the level would make some speakers much louder than others. Maybe ther movie studios master the audio for a specific decibel level, but I really dont think that has anything to do with "0db" on a receiver unless you are using all THX specific speakers and settings.

Ya, I had always thought that 0db means it isn't adding or taking away from the signal level, just like 0 on a sound board. I had no idea that 0 was supposed to be some specific SPL in the system. That doesn't really make sense to me since different sources hae different signal levels from them that all produce different volume at any given db setting on the receiver. And all speakers have different sensitivity so turning up the level would make some speakers much louder than others. Maybe ther movie studios master the audio for a specific decibel level, but I really dont think that has anything to do with "0db" on a receiver unless you are using all THX specific speakers and settings.

You clearly don't understand the concept and should do a little research on the subject. You might start with the link in sptrout's post.

I don't see what dialnorm has to do with this. Reference levels are absolute SPLs: 85 dB SPL average, 105 dB SPL peak for main speakers, 115 dB SPL for the LFE channel, and yes, 121 dB SPL for the subwoofer combination of LFE and redirected bass. According to every discussion I have read, these are the values defined as the motion picture audio re-recording standards. I have never seen dialnorm factored into any such discussion on reference levels, and there have been plenty of them on this forum. Please provide links to any information that relates dialnorm to reference level and I will be happy to review it and change my views if they are incorrect.



A lot of people have their heads burrried in the sand. I can't help with the thought process of posters on this forum.

Take the movie War of the Worlds. WOTW DD uses a dialnorm value of -23. A dialnorm value of -23 reduces volume levels by 8 dB. This means that all peak the potential maximum peak SPL levels will be reduced by 8 dB. LFE maximum will be reduced fron 115 dB SPL to 107 dB SPL.

When you compare WOTW DTD with WOTW DD, the DTS version plays back 8 dB higher in volume level than the DD version. Which version plays at reference level when the master volume is set to the calibrated reference level position on the master volume control? The DTS version that does not use dialnorm, or the DD version that does use dialnorm?

Ya, I had always thought that 0db means it isn't adding or taking away from the signal level, just like 0 on a sound board. I had no idea that 0 was supposed to be some specific SPL in the system. That doesn't really make sense to me since different sources hae different signal levels from them that all produce different volume at any given db setting on the receiver. And all speakers have different sensitivity so turning up the level would make some speakers much louder than others. Maybe ther movie studios master the audio for a specific decibel level, but I really dont think that has anything to do with "0db" on a receiver unless you are using all THX specific speakers and settings.



That is what the speaker trims do - they balance out the system for different speaker sensitivities and speaker distances from the listening position. We are not talking about 0 dB on the trims.

The 0 dB number that is being talked about here is in reference to the master volume control setting. Turning the volume up or down with the master volume control applies to all channels at the same time. Speaker sensitivity does not matter.

I have a Yamaha RX-V1800. When using the internal test tones at 0db, I get 75db for each speaker with the trims in the + or - 2.5 range. It's not a THX unit and it seems to be calibrating to reference level as I understand it.

As for playback, different sources and different Blu Ray movies seem to have different levels, so it does not seem that 0db will be a reference listening level for all sources anyway.

I guess I wonder why reference level is so important if, as I always read here, it's unlikely that most our systems and senses can really tolerate reference levels in the home.

I have a Yamaha RX-V1800. When using the internal test tones at 0db, I get 75db for each speaker with the trims in the + or - 2.5 range. It's not a THX unit and it seems to be calibrating to reference level as I understand it.

As for playback, different sources and different Blu Ray movies seem to have different levels, so it does not seem that 0db will be a reference listening level for all sources anyway.

I guess I wonder why reference level is so important if, as I always read here, it's unlikely that most our systems and senses can really tolerate reference levels in the home.

2 things. First, reference level does not mean that the sound on any particular movie will be at any specific SPL. It means that your system is calibrated so that at reference, the SPL in your room will be the same as the SPL that the mixer heard, and intended for the movie theater, when mixing the movie. (Bcause every movie mixing room is calibrated to the same reference level, at least for front 3 and LFE channel - - they actually calibrate surrounds slightly differently). A movie might be mixed really quiet or really loud, but if you are at reference (with the caveat below) you will hear it at the level the mixer intended for the theater.

Second, as mentioned above, Dialnorm (which exists for both DD and DTS, but is more routinely implemented on DD) does not change anything within the mix itself, but does send a message to the processor that may turn down the overall volume. The typical Dolby dialnorm setting is -4. My old receiver gave me know way to know, but my Denon displays the dialnorm setting briefly when you start playing the movie.

Dialnorm is intended only for home use - - it is not present on movie prints and they play at full volume. So if you have your system calibrated to reference and the dialnorm is -4, you would have to turn up 4 dB to be back at reference (with a potential caveat discussed below).

It seems to me that I've read that THX's reference setup takes "typical" dialnorm into account and is therefore 4 dB louder than it would otherwise be. But I could be misremembering that.

Knowing where reference level is on your system may be of no interest whatsoever to you. For some of us, it is a matter of at least intellectual interest, as we may only very occasionally play a portion of a movie at reference in order to see what it sounds like in our rooms. Many people listen at 10 to 20 dB below reference quite happily. And if you're not obsessive about knowing where you are in relation to reference levels, you'll never need to think about it.

Another thing that reference setup does is enable aftermarket programs like Audyssey Dynamic EQ and Dynamic Volume, or Dolby Volume, to make appropriate corrections to the sound based on the degree of departure from reference. Our ears are increasingly less sensitive to bass, for example, so as we turn down, the effect, to our ear/brain system, is that bass is turned down more than the rest of the sound. These products endeavor to correct the output from our systems to account for the changes in our sensitivity to sounds based on departure from reference. Without knowing what reference is, these systems become, at best, a crapshoot. So for example many find that dynamic EQ is overkill on music CDs because they are mixed with no particular loudness reference in mind, and usually are much louder on the disk (which means, somewhat confusingly, that their effective "reference level" is LOWER). There are ways to deal with this, however, and many of us apply these corrections to music as well as music quite happily.

Sorry for the long winded post . . .

A lot of people have their heads burrried in the sand. I can't help with the thought process of posters on this forum.

Take the movie War of the Worlds. WOTW DD uses a dialnorm value of -23. A dialnorm value of -23 reduces volume levels by 8 dB. This means that all peak the potential maximum peak SPL levels will be reduced by 8 dB. LFE maximum will be reduced fron 115 dB SPL to 107 dB SPL.

When you compare WOTW DTD with WOTW DD, the DTS version plays back 8 dB higher in volume level than the DD version. Which version plays at reference level when the master volume is set to the calibrated reference level position on the master volume control? The DTS version that does not use dialnorm, or the DD version that does use dialnorm?

I ask again: Please provide a link to some documentation that addresses dialnorm's relationship with reference level. I would like to read it. I have searched all over the Dolby, DTS, and THX websites and found nothing discussing dialnorm and reference level. The only thing I find is 85 dB, 105 dB, and 115 dB. 107 dB is NOT reference level.

*Snip*

Sorry for the long winded post . . .
Excellent stuff! Thanks for being long-winded. :)

Craig

That is what the speaker trims do - they balance out the system for different speaker sensitivities and speaker distances from the listening position. We are not talking about 0 dB on the trims.

The 0 dB number that is being talked about here is in reference to the master volume control setting. Turning the volume up or down with the master volume control applies to all channels at the same time. Speaker sensitivity does not matter.

So it is your opinion that "0" on the master volume is just a random setting that doesn't mean anything?

All the talk, and threads, about reference level being obtained by first having gear capable of reference level and secondly, properly calibrating your system so that "0" is reference are wrong?

How, in your opinion, is reference level obtained by a non-THX system? Or is there such a thing as reference level, again, in your opinion?

So it is your opinion that "0" on the master volume is just a random setting that doesn't mean anything?

All the talk, and threads, about reference level being obtained by first having gear capable of reference level and secondly, properly calibrating your system so that "0" is reference are wrong?

How, in your opinion, is reference level obtained by a non-THX system? Or is there such a thing as reference level, again, in your opinion?

IMO the anwser to your fist question is maybe yes, maybe no. With newer AVRs the system will automatically setup the system levels to where "0" actually means 75dB SPL at the first test position. Older AVRs are a different story. I used to have a Denon 3300 and I did set the trims so that when the master level was set at "0" the sytem was calibrated for Reference Level. However, I could just as easily set the trims such that the master level display would have shown about any number I either wanted, or if I did not know any better. (For example I could have set the master level to say -10 and then went into the speaker setup screen and still set the trims for 75dB SPL. Therefore, -10 would have been my "reference level").

On systems that are not properly calibrated, "0" or any other dB number on the display is meaningless because it is a dB number that is not referenced to anything.

So it is your opinion that "0" on the master volume is just a random setting that doesn't mean anything?

All the talk, and threads, about reference level being obtained by first having gear capable of reference level and secondly, properly calibrating your system so that "0" is reference are wrong?

How, in your opinion, is reference level obtained by a non-THX system? Or is there such a thing as reference level, again, in your opinion?



That was answered in post # 4.

Any particular receiver may or may not be designed so 0 dB on the master volume is equal to reference level. Whatever number on the master volume gives you 75 dB SPL when measured at the listening position with the receiver's internal test tones is the reference level setting for the master volume control.

For my receiver -22 dB on the master volume control is the calibrated reference level setting (AKA 75 dB SPL measured at listening position via internal test tones).

Some receivers use an absolute scale and not a dB scale. Some receivers require calibration for reference level to be 0 dB on the master volume. Some receivers can be fiddled with to force 0 dB to be reference level, but that does not mean the trim settings are correct (AKA you could clip).

My point is one should never claim that 0 dB on every master volume control equates to reference level in every properly calibrated receiver.

I ask again: Please provide a link to some documentation that addresses dialnorm's relationship with reference level. I would like to read it. I have searched all over the Dolby, DTS, and THX websites and found nothing discussing dialnorm and reference level. The only thing I find is 85 dB, 105 dB, and 115 dB. 107 dB is NOT reference level.



You have done some research, now you should think about what you have read.

1 + 1 = 2


Unless you have a dialnorm readout on your receiver's display, you will not know what dialnorm values are used on any specific DD DVD.

Some THX specifications:

http://www.hometheaterhifi.com/volume_13_1/feature-article-thx-1-2006-part-1.html


Quoted from Part-2 at the bottom:

"Another key element that THX requires for receivers and SSPs is the reference setting for volume control. When a system is calibrated according to the manufacturer’s instructions, "0.0 dB" on the volume control corresponds to reference level playback. In turning the volume down, the volume level is expressed in -dB, or how many dB below reference level you are."



For some reason uninformed people require that non-THX equipment must conform to THX specifications.

You have done some research, now you should think about what you have read.

1 + 1 = 2


Unless you have a dialnorm readout on your receiver's display, you will not know what dialnorm values are used on any specific DD DVD.

Yes, I have.

Reference level is 85 dB SPL average, 105 dB SPL peak for the mains, and 115 db SPL peak for the LFE channel. If you want to take dialnorm into consideration, it is irrelevant WHERE on the volume knob (except possibly THX AVRs and Pre-Pros) those levels are achieved. They are absolutes.

Yes, I do have a dialnorm display on my Onkyo TX-SR706, not that I really care about it.

Yes, I have.

Reference level is 85 dB SPL average, 105 dB SPL peak for the mains, and 115 db SPL peak for the LFE channel. If you want to take dialnorm into consideration, it is irrelevant WHERE on the volume knob (except possibly THX AVRs and Pre-Pros) those levels are achieved. They are absolutes.

Yes, I do have a dialnorm display on my Onkyo TX-SR706, not that I really care about it.



That "dialnorm" display tells you how much volume is being reduced from DD reference level. You can never hit those reference level peaks unless the dialnorm value is set to a -31 value on the DD DVD. It makes no difference whether you care about it or not.

Is that a THX unit? Do you have a dialnorm readout, or a dialnorm offset readout? A dialnorm readout will show -31 for no volume reduction.

That "dialnorm" display tells you how much volume is being reduced from DD reference level. You can never hit those reference level peaks unless the dialnorm value is set to a -31 value on the DD DVD. It makes no difference whether you care about it or not.

Is that a THX unit? Do you have a dialnorm readout, or a dialnorm offset readout? A dialnorm readout will show -31 for no volume reduction.

From the article you linked to:

"A few words on "Reference Level"

Before we start talking about the pieces and parts, we first need to take a quick refresher on the concept of "Reference Level", as you are going to be hearing that term quite a bit in the coming paragraphs. Simply stated, Reference Level is a standard, known, predictable and reproducible playback volume level. When movie sound tracks are crafted, they are done so on systems which are locked at this level. The sound artist does not play around with a big volume knob when doing his/her work. If the sound artist wants something to be loud, they make that sound loud within the sound track. When they want something to be soft, they make that element soft within the sound track. Movie theaters set their playback level by the exact same rules, so when the movie is shown, you hear EXACTLY what the sound artist heard when they were making the piece. Loud, soft, in-between, it's all there, and no one touches the master volume knob over the course of a two-hour movie.

To achieve THX certification, components must play at this reference level without breaking, distorting, buzzing, rattling or any other distracting effects.

Reference level is by any definition, objective or subjective, quite loud. It basically mirrors the dynamic range of the studio system, which in the case of all movie sound tracks, is 105 dB. Any single channel of the system is calibrated to play 0 dB FSD (the loudest sound the sound track can contain) at 105 dB (115 dB for the LFE channel). While that is really, REALLY loud, its important to remember that there is 105 dB of dynamic range and the artist can put a sound at any level they want. So while a system's volume may be set to reference level, dialogue within the sound track can, and most often is, at a normal, natural level. Reference level, with the dynamic range available, permits a movie to have that normal, natural dialogue, and then suddenly a spectacular, loud car chase without anyone touching the volume control. Every element in the sound track comes out as it should.

Now, having said all that, watching a movie at reference level in a home theater is almost never done. It can be extremely loud to begin with, but the close spaces typical of home theaters make it perceptibly even more so. Reference level is still very important in home theater though for several reasons. Because it is the absolute loudest a sound track should ever be played, its fairly intuitive that its a good idea to have a system that can competently go that loud. It gives you a sort of "safe maximum" volume level, even though you may never push it that high. Even more important though is knowing what volume you are at RELATIVE to reference level because if we go too low, we literally lose the quietest sounds since they are pushed below the audible threshold, surrounds lose their presence, the perceived spectral distribution of the track is altered, and dialogue intelligibility suffers."

An article on Dialnorm:

http://www.hometheaterhifi.com/volume_7_2/feature-article-dialog-normalization-6-2000.html

In neither article do I see anything that supports your statement that "You can never hit those reference level peaks unless the dialnorm value is set to a -31 value on the DD DVD." To tell you the truth, that statement makes no sense to me at all.

Well, if you turn down the signal going into the receiver's system by 4 dB, it just stands to reason (so much that maybe people don't come right out and say it) that the level coming out is four decibels quieter than it otherwise would have been. I don't know any other way to say it. It is clear that dialnorm sometimes results in the level being lowered. The level cannot be lowered without the levels being, um, lower.

Well, if you turn down the signal going into the receiver's system by 4 dB, it just stands to reason (so much that maybe people don't come right out and say it) that the level coming out is four decibels quieter than it otherwise would have been. I don't know any other way to say it. It is clear that dialnorm sometimes results in the level being lowered. The level cannot be lowered without the levels being, um, lower.

Then you just, well, turn the volume knob UP 4 dB and you are back where you started.

All I am saying is that "reference level(s)" are defined, absolute values regardless of dialnorm. I have conceded that "reference" can correspond to any marking on the volume knob you choose, exept for THX which is always 0 dB.

And to answer J_Palmer_Cass's last question, "yes" my AVR is THX certifed and the display is "dialnorm offset."

Then you just, well, turn the volume knob UP 4 dB and you are back where you started.


But if your receiver didn't tell you what the dialnorm offset was, you would have assumed running your receiver at 0 would be reference, when in fact you would need to listen at +4 to hear reference level as the sound engineer intended.

But if your receiver didn't tell you what the dialnorm offset was, you would have assumed running your receiver at 0 would be reference, when in fact you would need to listen at +4 to hear reference level as the sound engineer intended.

Okaaaayyy ...... :confused:

All I am contending is that the following statement is false:

"You can never hit those reference level peaks unless the dialnorm value is set to a -31 value on the DD DVD."

There is nothing in any post or link that supports that statement that I see.

Okaaaayyy ...... :confused:

All I am contending is that the following statement is false:

"You can never hit those reference level peaks unless the dialnorm value is set to a -31 value on the DD DVD."

There is nothing in any post or link that supports that statement that I see.

Absolutely right. Looks like everybody has been making sort of incomplete statements and talking past each other. Bluesky, it sounded like you were saying that reference at zero was reference and nothing dialnorm does changes that. That's at least what I was responding to. I, on the ohter hand, assumed that "everybody" would somehow "know" that my statements were limited to what happens when you leave the volume know at nominal zero, but dialnorm has changed things. We agree, as nearly as I can tell, that if dialnorm changes levels, we can still get ourselves to actual reference (assuming we know the offset) via our volume controls.

Much ado, it seems, about nothing.

Unless your volume control maxes out at 0 and you cannot go above that.

Absolutely right. Looks like everybody has been making sort of incomplete statements and talking past each other. Bluesky, it sounded like you were saying that reference at zero was reference and nothing dialnorm does changes that. That's at least what I was responding to. I, on the ohter hand, assumed that "everybody" would somehow "know" that my statements were limited to what happens when you leave the volume know at nominal zero, but dialnorm has changed things. We agree, as nearly as I can tell, that if dialnorm changes levels, we can still get ourselves to actual reference (assuming we know the offset) via our volume controls.

Much ado, it seems, about nothing.

Concur on both points.

Unless your volume control maxes out at 0 and you cannot go above that.

I think everyone here now agrees that for a non-THX receiver, "reference" could be at any value on the volume knob and that only on a THX receiver is "reference" defined as 0 dB.

I guess I'll have to look into how Audyssey's Dynamic EQ is implemented in the Onkyo's with regard to dialnorm. It's adjustments could be off slightly if not taken into account.

I guess I'll have to look into how Audyssey's Dynamic EQ is implemented in the Onkyo's with regard to dialnorm. It's adjustments could be off slightly if not taken into account.

This has been discussed on the Audyssey thread. Dynamic EQ is referenced to 0 dB (75 dB SPL, -30 dbfs) as set during the Audyssey measurements.

I think everyone here now agrees that for a non-THX receiver, "reference" could be at any value on the volume knob and that only on a THX receiver is "reference" defined as 0 dB.

nope. Every Audyssey auto setup sets reference at zero. My non-THX Denon receiver has 0 dB as reference. No magic there, after all, just setting levels so a known input yeilds a known SPL in the listening seat.

http://home.comcast.net/~schiz/SoundOfMusic.jpg

I guess I'll have to look into how Audyssey's Dynamic EQ is implemented in the Onkyo's with regard to dialnorm. It's adjustments could be off slightly if not taken into account.

From Chris (Audyssey) on the Audyssey thread


All I can say is that Dynamic EQ (and Dynamic Volume) make an adjustment using dialnorm information. In practical terms this is a very small effect. Unity gain happens with dialnorm set to –31 dB and 4 dB of difference is not going to make huge changes in what Dynamic EQ is adjusting for.

nope. Every Audyssey auto setup sets reference at zero. My non-THX Denon receiver has 0 dB as reference. No magic there, after all, just setting levels so a known input yeilds a known SPL in the listening seat.

My statement said: "I think everyone here now agrees that for a non-THX receiver, "reference" could be at any value on the volume knob and that only on a THX receiver is "reference" defined as 0 dB."

"could be at any value" would include 0 dB on a non-THX AVR. :D

My original statement was going to say "and that on a THX receiver "reference" is defined as 0 dB." That probably would have been better. :D

From Chris (Audyssey) on the Audyssey thread


All I can say is that Dynamic EQ (and Dynamic Volume) make an adjustment using dialnorm information. In practical terms this is a very small effect. Unity gain happens with dialnorm set to –31 dB and 4 dB of difference is not going to make huge changes in what Dynamic EQ is adjusting for.

Ok. My statement above on this subject is more or less incorrect. Or more or less correct, depending on your point of view. :D

That's what it's really all about, right? :D


http://home.comcast.net/~schiz/SoundOfMusic.jpg

Having read most of this thread and another recent thread about Dolby Dialnorm, I will try to add, rather than a few more words, an equation to be admired or scorned (because I like summarizing with equations when appropriate). This has one over-simplifying assumption, that the sound comes from only one channel at a time, either main or LFE.

Let R (dB) be the level of the recorded sound, at some point in the recording, relative to digital full scale (0dBFS); note that R<=0.
Let L=1 if sound is from LFE channel, L=0 from main channel.
Let E (dB) be the Dialnorm encoding setting on the disk; note that E<=31.
Let V (dB) be the the master volume setting that we select on our calibrated receiver (actual displayed number).
Let VR (dB) be the master volume setting at reference level (on a THX receiver, VR=0 "by definition").

Now we have all the information needed to calculate S (dB), the SPL heard or measured at the listener position:

S = 105 + 10*L + (V - VR) - (31 - E) + R

^

and per Sivadselim, I bet someone could set my equation to music if they really tried. "Doe, a decibel ..."

Reference level is by any definition, objective or subjective, quite loud. It basically mirrors the dynamic range of the studio system, which in the case of all movie sound tracks, is 105 dB. Any single channel of the system is calibrated to play 0 dB FSD (the loudest sound the sound track can contain) at 105 dB (115 dB for the LFE channel). While that is really, REALLY loud, its important to remember that there is 105 dB of dynamic range and the artist can put a sound at any level they want. So while a system's volume may be set to reference level, dialogue within the sound track can, and most often is, at a normal, natural level. Reference level, with the dynamic range available, permits a movie to have that normal, natural dialogue, and then suddenly a spectacular, loud car chase without anyone touching the volume control. Every element in the sound track comes out as it should.


http://www.hometheaterhifi.com/volume_7_2/feature-article-dialog-normalization-6-2000.html

In neither article do I see anything that supports your statement that "You can never hit those reference level peaks unless the dialnorm value is set to a -31 value on the DD DVD." To tell you the truth, that statement makes no sense to me at all.


It makes no sense to you because you don't know what you are talking about. You are just parroting numbers.

WOTW is a specific DD DVD that does use a DN value of -23. When dialnorm reduces the volume by 8 dB, then all signals on all channels will be reduced by 8 dB.

When you reduce your SPL level by 8 dB via dialnorm, your maximum peak SPL will be 97 dB (105 dB - 8 dB = 97 dB) for the main channels and 107 dB (115 dB - 8 dB = 107 dB) for the LFE channel.

Tell me how you can hit any level higher than that assuming the master volume is set to the calibrated DD reference level position and DD DVD dialnorm has a value of -23.

Note that the DTS version of WOTW does not use dialnorm, so it plays back 8 dB louder than the DD version on a non THX receiver.

Having read most of this thread and another recent thread about Dolby Dialnorm, I will try to add, rather than a few more words, an equation to be admired or scorned (because I like summarizing with equations when appropriate). This has one over-simplifying assumption, that the sound comes from only one channel at a time, either main or LFE.

Let R (dB) be the level of the recorded sound, at some point in the recording, relative to digital full scale (0dBFS); note that R<=0.
Let L=1 if sound is from LFE channel, L=0 from main channel.
Let E (dB) be the Dialnorm encoding setting on the disk; note that E<=31.
Let V (dB) be the the master volume setting that we select on our calibrated receiver (actual displayed number).
Let VR (dB) be the master volume setting at reference level (on a THX receiver, VR=0 "by definition").

Now we have all the information needed to calculate S (dB), the SPL heard or measured at the listener position:

S = 105 + 10*L + (V - VR) - (31 - E) + R




Incorrect formula.

It makes no sense to you because you don't know what you are talking about. You are just parroting numbers.

WOTW is a specific DD DVD that does use a DN value of -23. When dialnorm reduces the volume by 8 dB, then all signals on all channels will be reduced by 8 dB.

When you reduce your SPL level by 8 dB via dialnorm, your maximum peak SPL will be 97 dB (105 dB - 8 dB = 97 dB) for the main channels and 107 dB (115 dB - 8 dB = 107 dB) for the LFE channel.

Tell me how you can hit any level higher than that assuming the master volume is set to the calibrated DD reference level position and DD DVD dialnorm has a value of -23.

Note that the DTS version of WOTW does not use dialnorm, so it plays back 8 dB louder than the DD version on a non THX receiver.

"Frankly, my dear, I don't give a damn."

So it is your opinion that "0" on the master volume is just a random setting that doesn't mean anything?

All the talk, and threads, about reference level being obtained by first having gear capable of reference level and secondly, properly calibrating your system so that "0" is reference are wrong?

They only apply to THX receivers.

How, in your opinion, is reference level obtained by a non-THX system? Or is there such a thing as reference level, again, in your opinion?

I have a non-THX hk-254. 0 dB means max power output given max analog input. To know where Reference lies on my volume dial, I play a calibration disk and use my SPL meter. I get -16 dB on my dial.

Incorrect formula.

Terse criticism.

I tried to write an equation for my own understanding, as well as hope that such a summary would be useful to others. What type of error(s) do you find: sign error, omitted term, incorrect definition, ...?

Terse criticism.

I tried to write an equation for my own understanding, as well as hope that such a summary would be useful to others. What type of error(s) do you find: sign error, omitted term, incorrect definition, ...?



It should only be that easy to write a formula that will give you accurate results. I see plenty of errors in your formula, but let's leave it at that.

A somewhat related peak SPL discussion can be seen in the link below.

The title is: Do 115 dB peaks on the LFE channel represent what you hear in a movie theater?


http://www.avsforum.com/avs-vb/showthread.php?t=1171121&highlight=

They only apply to THX receivers.


I have a non-THX hk-254. 0 dB means max power output given max analog input. To know where Reference lies on my volume dial, I play a calibration disk and use my SPL meter. I get -16 dB on my dial.

It also, apparently, applies to every AVR using Audyssey.

I know what you mean. I have an older Rotel that has increments increasing from "0". So I agree there are a lot of exceptions.

It makes no sense to you because you don't know what you are talking about. You are just parroting numbers.

WOTW is a specific DD DVD that does use a DN value of -23. When dialnorm reduces the volume by 8 dB, then all signals on all channels will be reduced by 8 dB.

When you reduce your SPL level by 8 dB via dialnorm, your maximum peak SPL will be 97 dB (105 dB - 8 dB = 97 dB) for the main channels and 107 dB (115 dB - 8 dB = 107 dB) for the LFE channel.

Tell me how you can hit any level higher than that assuming the master volume is set to the calibrated DD reference level position and DD DVD dialnorm has a value of -23.

Note that the DTS version of WOTW does not use dialnorm, so it plays back 8 dB louder than the DD version on a non THX receiver.

How I would reach "real" reference on WOTW is this: WHen the movie starts and the dialnorm value comes up on my receiver, I would turn my volume level up to +8. "Problem" solved, as discussed in several posts above.

Dialnorm is just not the end of the world that some would have it to be. BUT I fully agree that it has, in practice, not necessarily helpful to use it on DVDs or Blu-rays. It would be great if they'd use it correctly in the broadcast world, though.

How I would reach "real" reference on WOTW is this: WHen the movie starts and the dialnorm value comes up on my receiver, I would turn my volume level up to +8. "Problem" solved, as discussed in several posts above.





You solved a problem that is not a problem. How many people listen to their systems at the calibrated reference level position on the master volume control? The nominal master volume level below calibrated reference level that I tend to use for loud action movies is about - 6dB for DD material, and -10 dB for DTS material.

I would just use the DTS version of WOTW and bypass the entire DN issue!

For that matter, how many people have systems that can playback at full reference level?


According to the following calculator, a single speaker played on my system will only hit 100 dB SPL before I run out of power. In theory, that leaves me 5 dB short on my main speakers for playback a loud action movie at full reference level assuming that dialnorm is not used in the DD DVD.



Spl Calculator link (http://myhometheater.homestead.com/splcalculator.html)






Dialnorm is just not the end of the world that some would have it to be. BUT I fully agree that it has, in practice, not necessarily helpful to use it on DVDs or Blu-rays. It would be great if they'd use it correctly in the broadcast world, though.


Dialnorm is required in order to let DRC perform properly. When you downmix in a DVD player and use the analog outputs, DD uses those features. DTS material can not be downmixed in a standard DVD player.

J-Palmer_Cass - You appear to be confusing two issues here. Dialnorm reduces overall volume on playback by the amount of the DN offset from -31. But, if you calibrate your system using a disc with tones recorded using the Dolby standard, then reference on your receiver will compensate for the usual DN reduction. Tracks with DN values of -27 will produce 105dB peaks, with 115dB peaks for LFE. And, if you play a disc without DN, reference will produce outputs that are 4dB too loud.

You solved a problem that is not a problem. How many people listen to their systems at the calibrated reference level position on the master volume control? The nominal master volume level below calibrated reference level that I tend to use for loud action movies is about - 6dB for DD material, and -10 dB for DTS material.

I would just use the DTS version of WOTW and bypass the entire DN issue!

For that matter, how many people have systems that can playback at full reference level?


According to the following calculator, a single speaker played on my system will only hit 100 dB SPL before I run out of power. In theory, that leaves me 5 dB short on my main speakers for playback a loud action movie at full reference level assuming that dialnorm is not used in the DD DVD.



Spl Calculator link (http://myhometheater.homestead.com/splcalculator.html)








Dialnorm is required in order to let DRC perform properly. When you downmix in a DVD player and use the analog outputs, DD uses those features. DTS material can not be downmixed in a standard DVD player.


I was answering somebody else's question. I very seldom listen above -10 dB and so it is all a moot point to me.

I don't see how Dialnorm is necessary for DRC. Without dialnorm, DRC would act like dialnorm was set at -0 all the time. No biggie. What dd and dts, as far as I know, use to downmix are downmix coefficients set at the time the movie is encoded. Again, I can't think of anything crucial about dialnorm to allow downmixing. Downmixing and DRC may well take dialnorm into account, but if it were not there, the would not need to. Unless I'm missing something.

Dialnorm is required in order to let DRC perform properly. When you downmix in a DVD player and use the analog outputs, DD uses those features. DTS material can not be downmixed in a standard DVD player.??? You aren't claiming that a DVD player simply sends L/R over the stereo outputs from DTS sources instead of a downmix, are you?

I don't see how Dialnorm is necessary for DRC. Without dialnorm, DRC would act like dialnorm was set at -0 all the time. No biggie. What dd and dts, as far as I know, use to downmix are downmix coefficients set at the time the movie is encoded. Again, I can't think of anything crucial about dialnorm to allow downmixing. Downmixing and DRC may well take dialnorm into account, but if it were not there, the would not need to. Unless I'm missing something.
DN sets the proper "center point" for DRC. Audio above the center point gets lowered in volume and audio below the center point gets increased in volume. Without a DN value, DRC uses an assumed average dialog level, which may be wrong. That's part of the reason why DRC is limited to Dolby sources. Of course, you can still do dynamic range compression with any source. That's how night mode works on many players and receivers. It just won't be quite as precise without a DN reference point for average dialog.

I was answering somebody else's question. I very seldom listen above -10 dB and so it is all a moot point to me.

I don't see how Dialnorm is necessary for DRC. Without dialnorm, DRC would act like dialnorm was set at -0 all the time. No biggie. What dd and dts, as far as I know, use to downmix are downmix coefficients set at the time the movie is encoded. Again, I can't think of anything crucial about dialnorm to allow downmixing. Downmixing and DRC may well take dialnorm into account, but if it were not there, the would not need to. Unless I'm missing something.



Wrong, you are missing everything.


http://emusician.com/tutorials/emusic_secret_encoder_ring/

Wrong, you are missing everything.


http://emusician.com/tutorials/emusic_secret_encoder_ring/

I see that DRC uses the dialnorm as an input. I'll even concede that it adds value. But if it's not possible to do dynamic range control without having dialnorm, then Audyssey Dynamic EQ cannot possibly work on DTS soundtracks that have no dialnorm setting. Yet it seems to do so. I didn't spend a bunch of time looking for how dialnorm might affect downmixing . . . doesn't seem necessary to me. That's not to say you can't use it. I said you can use it. Just that it's not a critical part of the thing. Dialnorm, as I understand it, was developed to equalize dialog levels among different programs. The use of dialnorm as an input into downmixing or DRC does not mean that these could not be done without dialnorm.

To clarify, I do see the point that having the dialnorm information allows at least potentially better setting of the onset of compression in the DRC process. And of course, it only stands to reason that as DD was building their wuite of products they made them inter-communicate in ways that were intended to maximize utility value and performance.

SO mostly I'm convinced . . .

I see that DRC uses the dialnorm as an input. I'll even concede that it adds value. But if it's not possible to do dynamic range control without having dialnorm, then Audyssey Dynamic EQ cannot possibly work on DTS soundtracks that have no dialnorm setting. Yet it seems to do so. I didn't spend a bunch of time looking for how dialnorm might affect downmixing . . . doesn't seem necessary to me. That's not to say you can't use it. I said you can use it. Just that it's not a critical part of the thing. Dialnorm, as I understand it, was developed to equalize dialog levels among different programs. The use of dialnorm as an input into downmixing or DRC does not mean that these could not be done without dialnorm.

To clarify, I do see the point that having the dialnorm information allows at least potentially better setting of the onset of compression in the DRC process. And of course, it only stands to reason that as DD was building their wuite of products they made them inter-communicate in ways that were intended to maximize utility value and performance.

SO mostly I'm convinced . . .

DRC or a so-called "night" mode is different from Dynamic EQ. DRC needs dialnorm to work, thats why it only works on DD. It does exactly what it is called, controls the dynamic range.

Dynamic EQ on the other hand works with any material because it is, more or less, a fancy loudness function. It works by manipulating FR as well as volume level.

Both techs work, just differently. One decreases overall dynamics, the other boosts the frequencies that are hard to hear at decreased volumes.

DRC doesn't "need" a dialnorm value. It just works better with one when average dialog is not at the expected level.

DRC doesn't "need" a dialnorm value. It just works better with one when average dialog is not at the expected level.

Then why doesn't DRC work with DTS material?

edit: I just read something about DRC being a Dolby preferred process and that it works in the processor after any dialnorm values are applied.

http://etvcookbook.org/audio/drc.html

Not sure that it all applies, but.........

I'm sure Roger Dressler could weigh in on this and add more info. Here (http://www.hometheaterhifi.com/volume_7_2/feature-article-dialog-normalization-6-2000.html) is an article he provided info for.

DRC doesn't "need" a dialnorm value. It just works better with one when average dialog is not at the expected level.


Yes it does. Dialnorm is used to calibrate the content level so it ends up in the DRC null band.

Read Appendix C in the link below. For that matter, if you have the interest read the entire DD Encoding Guideline.


Dolby Digital Encoding Guidelines link (http://web.archive.org/web/20040716131627/http://www.dolby.com/tech/L.mn.0002.DDPEG1.pdf)

Then why doesn't DRC work with DTS material?
Dynamic Range Control is a Dolby system. Average dialog is played at the recorded volume level. The level of quieter sounds (such as whispers) is boosted and the level of louder sounds (such as explosions) is lowered. Of course, to work optimally, the software needs to know the level of average dialog. That's where dialnorm gets involved. But, that's the only role that DN plays in the Dolby DRC system - to identify the level average dialog.

These days DTS encoders also include dialnorm values, btw. But, there's more than just DN involved in the Dolby Dynamic Range Control system.

These days DTS encoders also include dialnorm values, btw.




They always did. DTS chose not to use if for DVD production. You can not downmix a DTS DVD to 2 channel analog output in a DVD player, so perhaps there was no reason to use it for a DTS DVD.

DTS also has some type of DRC available, but they chose to not use it for DVD production.

Not sure what is used for the recent BlueRay disks!

Yes it does. Dialnorm is used to calibrate the content level so it ends up in the DRC null band.Pardon my lack of clarity. The Dolby Dynamic Range Control system uses dialnorm. But, dynamic range compression does not require a dialnorm value. Night Modes on various players and receivers compress dynamic range without a dialnorm reference point and they work independent of the Dolby DRC system. I think that distinction is clear in my previous posts. But, if not, my apologies.

Now, are you going to explain that claim of yours that DTS tracks can't be downmixed? EDIT: I see an answer now in the post above, although I must admit I don't understand it. As far as I know, DTS tracks on Blu-ray players can be downmixed for analog stereo output. Are you saying that is not true of DVD players? What gets output then? If the player's digital output is set to PCM instead of bitstream, is it downmixed to two channels? And what happens with a legacy DTS bitstream that gets decoded in a receiver? Are you saying the AVR can't downmix the multichannel track for stereo output? Or, is this just about an odd quirk of the analog stereo output of DVD players?

They always did. DTS chose not to use if for DVD production.

DTS also has some type of DRC available, but they chose to not use it for DVD production.

Not sure what is used for the recent BlueRay disks!dts-HD decoders process dialnorm just like Dolby decoders. If there's a value other than -31, the output level is attenuated by the amount of the offset. DTS encoders default to -31 and that value is rarely changed by producers. But, some dts-MA releases use dialnorm offsets - Watchmen, for example.

DRC or a so-called "night" mode is different from Dynamic EQ. DRC needs dialnorm to work, thats why it only works on DD. It does exactly what it is called, controls the dynamic range.

Dynamic EQ on the other hand works with any material because it is, more or less, a fancy loudness function. It works by manipulating FR as well as volume level.

Both techs work, just differently. One decreases overall dynamics, the other boosts the frequencies that are hard to hear at decreased volumes.

Yep. I meant to refer to Dynamic Volume.

Since I did not design the DD DRC, I can't really state what difference it might make if there was no dialnorm to work with. Doubtless, if something at or near average dialog level is the "right" setting for what amounts to the compressor's "attack" setting, knowing that lets you set the compression more accurately. But it may not make much practical difference, as you'd use a soft knee onset, and the average dialog levels tend to fall within a range that likely would let a system work without the info.

One last point then I'll shut up. This is probably more of a question. My understanding of DRC is that it is "classic" compression: it does not differentially "turn up" anything. Like a dbx (just to pick one ourt of the air) compressor, it turns down the loud stuff based on settings provided, then turns everything back up (make-up volume) which has the effect of making the quiet parts louder. But it's significantly different, and less transparent than, either the new Dolby Volume product or its competitors including Dynamic Volume, at least in theory, in the ways that they increase volume of quiet parts . . .

My understanding of DRC is that it is "classic" compression: it does not differentially "turn up" anything. Like a dbx (just to pick one ourt of the air) compressor, it turns down the loud stuff based on settings provided, then turns everything back up (make-up volume) which has the effect of making the quiet parts louder.Actually, that's exactly what DRC does. Dynamic Range Control turns down the loud parts, does nothing to the center, and boosts the quiet parts. It does not do any overall volume adjustments.

Yep. I meant to refer to Dynamic Volume.

Since I did not design the DD DRC, I can't really state what difference it might make if there was no dialnorm to work with. Doubtless, if something at or near average dialog level is the "right" setting for what amounts to the compressor's "attack" setting, knowing that lets you set the compression more accurately. But it may not make much practical difference, as you'd use a soft knee onset, and the average dialog levels tend to fall within a range that likely would let a system work without the info.

One last point then I'll shut up. This is probably more of a question. My understanding of DRC is that it is "classic" compression: it does not differentially "turn up" anything. Like a dbx (just to pick one ourt of the air) compressor, it turns down the loud stuff based on settings provided, then turns everything back up (make-up volume) which has the effect of making the quiet parts louder. But it's significantly different, and less transparent than, either the new Dolby Volume product or its competitors including Dynamic Volume, at least in theory, in the ways that they increase volume of quiet parts . . .

I don't know how DRC actually works either, whether it turns down the loud stuff or lifts up the quiet stuff, or a combination of both. I agree with you though, if it was the end all, Dynamic Volume and Dynamic EQ wouldn't have been needed.