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HiroPro
11-23-2011, 06:45 AM
I usually am somewhere between -5 and -15dB from reference level, so not really ever at 0dB ;)

Almost all Dolby Digital 5.1 AC3 decoders apply a MANDATORY -4dB "Dialogue Normalization" to pass Dolby Labs licensing compliance if the meta data is detected in the stream. This is why you guys are getting within 5 db of reference as I bet it's on DD AC3 sources like DVD and HDTV movie broadcasts that contain the -27 metadata. If you flipped back to your TV input and it was LPCM 2 chan your ears would be blown off and I'm sure have been in the past.

I personally HATE Dialogue Normalization in the AC3 spec! That meta POOP is in MOST DVDs and broadcast movie AC3 encodes and IT'S TOTAL BS!

Sure it would be great for broadcast as anticipated IF broadcasters actually broadcasted in AC3 and media creators actually set the meta data value properly for the content. Most broadcasters are so concerned about 5.1 downmix to 2 chan for dialog/voice or simply don't know what their doing that they simply broadcast AC3 with the voice going to the left/right. I've seen 5.1 channel material downmixed to 2.0 and broadcast into a AC3 5.1 stream on HD channels many many times. I guess they don't trust your TVs 5.1 downmixing! Retarded really buy hey it's the sat/cable "head end" operators right and they ain't that bright with certain things... a lot of things...

It's yet another reason to use a PC for transport for audio AND VIDEO as the new video cards have been HDMI 1.4a compliant for some time and it's possible to undo the bloody -4 DB offset on AC3 content.

Yup AC3 Dialogue Normalization was a brainfart by all parties involved and also has given many an A/V nut or their second half a near heart attack switching from the DVD input to their TV input right as a +12 db obnoxious commercial spot airs!!! (those ads should be ILLEGAL)

Yup is scares/pisses off many hundreds of thousands of people every day! :eek:

PS All DVD authors that set -27 metadata should be SHOT!

PSS I seriously wouldn't doubt if it's actually killed a person! :confused: you know, given an older gent a heart attack like say... viagra or air turbulence or something... Personally I've jumped a couple times from this!

Fantom
11-23-2011, 11:35 AM
HiroPro, this is completely off topic for this thread. I'm more concerned though that you seem so angry. It really can't be good for your health.

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

A setting of -27 (where -31 applies 0 normalization offset) does indeed reduce output by 4dB, but it is in no way mandatory. It is, however, standard. Reference setup discs, such as Video Essentials and AVIA, use a setting of -27dB for their reference tones. So in fact, if you set up your system with such reference tones, then -27 DialNorm would in fact lead to 105dB peaks and proper reference level. (Note that -31 DialNorm content would actually be 4dB above reference then at your 0dB pre/pro setting).

Since dialog normalization is essentially (unless your decoder is doing something really stupid) the same as you changing the volume control, it leads to no reduction in dynamic range or loss of any bits.

Finally, DialNorm is one of the reasons that Dolby was chosen as the TV standard for digital content. It *could* be abused (not sure if there are regulations), but as we've both pointed out, the normal for a movie is -27. Now, a commercial can only go 4dB louder than that, but as much as 27dB quieter. So really, DialNorm makes it far more likely that the peak volume of a commercial will be quieter than a movie (which unfortunately says nothing of the compression and loudness of the soundwaves). I have listened to cable TV via Dolby w/DialNorm and via analog. Analog is awful for volume switches between shows and commercials. DialNorm greatly helps.

Also note that THX certified processors/receivers often attenuate DTS sources by 4dB to match Dolby reference level.

HiroPro
11-23-2011, 01:47 PM
My anger is a joke man... sorta like that comedian Lewis Black and other insiders would get it and laugh. I guess it's off topic but others were talking about their volume settings and that they find they are at -15 to -5 dB.

When I say mandatory what I'm saying is that if the decoder detects the -27 meta data it's mandatory that it apply the -4 db offset. In other words you can not over ride it and disable it. Have you ever noticed now it affects discrete channel leveling! This depends on the AVR and it's bass management. If your say rear surround is +5 db and all other channels at 0db for what ever reason it will perform a -9 db offset across the board on all channels! It's takes the level of the highest speaker db no matter the channel and adds it's +X db value to the offset to the entire channel count! This depends on high/low pass filter settings and speaker "size" setting. With it set to small on all channels with summing and high/low filters it does it properly meaning it performs the -4 dB equally to each channel. I have seen this on cheap AVRs and I wonder if that passes the Dolby silkscreen if it does that!


Since dialog normalization is essentially (unless your decoder is doing something really stupid) the same as you changing the volume control, it leads to no reduction in dynamic range or loss of any bits.

Yeah but it forces your amps to work harder to achieve the same SPL level (and YES it does lose bits see digitalhome.ca post)! Personally I think being within 5 db of reference to get a decent SPL is friggin ridiculous and this is even with sensitive speakers. You guys would never be at -5 dB for CD redbook or any other sources on your AVR! The idea Dolby had is that the -4 dB would help to create more amp reserve "poop" for "dynamic" scenes. The broadcast use of the meta data has never been used properly in the industry as I stated.


DialNorm makes it far more likely that the peak volume of a commercial will be quieter than a movie

That is the most BS I've heard in a long time in audio man...

Sure on paper for an EGGHEAD NOTION... in REALITY practically no commercials are in AC3 but PCM and even if they were the commercial author won't included the -27 meta data ANYWAY but set it to -31 duh. This causes the HUGE volume jump I spoke of when switching from DVD input to TV input on your AVR. Not only do you get the ridiculous volume level commercials are broadcast in but also a PLUS 4 dB increase from the AC3 source to the commercials because they are in PCM for the most part! This gain between an AC3 source and a PCM STB cable/sat commercial source can be as much as 12 dB if not higher !!! I've actually heard commercials clip/distort from this. That's more than enough to simply BLOW YOUR HEAD OFF when you switch from a movie to your TV STB if your volume is at -15-5 dB. Also you and the article author are DREAMING if you think TV commercial producers would set dialogue normalization to -27 or even -25 !!! ALL AC3 commercials I've ever heard are -31 !!!

Have you not experienced this and been startled switching from your DVD input to your TV input !?!

And hey enough of the patronizing talk about my health, anger and that "Finally," in the last paragraph.

BTW I have read that article prior and it still has no barring on what I'm talking about what so ever other than explaining the technology to Luddites.

owhh if it's such a great idea pray tell then why doesn't TrueHD or DTS-HD decoder also perform -4 on those movie sources ehh !?! It supports the same metadata and "dialogue normalization"... why do Bluray authors set it at -31 or simply not include the metadata?

I agree it's a great idea and great technology to have that metadata control in the stream but man... applied it really sucks as I'm most sure others will chime in about the volume blast switching from AC3 movie transport to TV STB. They will also chime in that with Bluray they haven't experienced this to the same extent/level.

Digitalhome.ca Post from a user that knows what he's talking about named unreal1080p (http://www.digitalhome.ca/forum/showthread.php?t=69985)

And this is why 90% of Blurays from big production houses in Hollywood with people that know what their doing make dam sure the Bluray authors DO NOT set the -27 "dialogue normalization" RETARDATION. Sony stated very publicly they WILL NOT set the -27 flag. Cameron made friggin sure on his Avatar Bluray!

PS Brian Florian doesn't know what he's talking about what so ever and he's just a PR audio writer reading from crib-notes provided by Roger Dressler & Mike Babbitt.

Jonnyozero3
11-23-2011, 01:52 PM
Hey guys, though interesting this is fairly off topic. Can you please take this to another thread? (Mods, any chance of creating a new one with posts 792, 793, 794?) Thanks.