Confused about Dolby TrueHD...

[thxpaul]

Ok so my RX-V3800 can decode dolby true hd..... the sony BDP-S500 can output it.... but I've got a fiber optic cable for sound connecting the two. Is this the problem? Do I HAVE to run the hdmi from the bluray TO the receiver and then one out from the receiver to my TV?

But then it says my player can decode internally and then just send it through the fiber optic cable. Is this truHD anymore?

The trueHD light on my receiver isn't lighting up so something's no go here.... please help a lost soul. Thanks!

[L.J.]

Yeah, you'll have to run HDMI from player to your AVR and then from your AVR HDMI out to your display.

Read this for more info:
http://forums.audioreview.com/showpost.php?p=232987&postcount=1

DTS has a nice explanation as well:
http://www.dts.com/DTS_In_Consumer_Products/HD_Home_Theater/Connections.aspx

[thxpaul]

Yeah, you'll have to run HDMI from player to your AVR and then from your AVR HDMI out to your display.

Read this for more info:
http://forums.audioreview.com/showpost.php?p=232987&postcount=1

DTS has a nice explanation as well:
http://www.dts.com/DTS_In_Consumer_Products/HD_Home_Theater/Connections.aspx

Thanks for the help. I have another question.

Before I run out and buy the extra cable, I'm wondering why it is that when I select TRUEHD from the DVD menu, the sound actually changes even though I'm only running a fiber optic cable. So I'm not getting the true uncompressed sound - so then why does the sound change somewhat when i select it?

Just curious!

[L.J.]

Thanks for the help. I have another question.

Before I run out and buy the extra cable, I'm wondering why it is that when I select TRUEHD from the DVD menu, the sound actually changes even though I'm only running a fiber optic cable. So I'm not getting the true uncompressed sound - so then why does the sound change somewhat when i select it?

Just curious!

This is because standard Dolby Digital & DTS have a higher bitrate on BR disc vs DVD. Pretty decent step in sound improvement but it's not HD audio.

[thxpaul]

This is because standard Dolby Digital & DTS have a higher bitrate on BR disc vs DVD. Pretty decent step in sound improvement but it's not HD audio.

Ok that makes sense now. How much better does a soundtrack sound in TRUE HD? Is it significantly audible? Or is it only something you'll hear with $10,000 amps

[L.J.]

Ok that makes sense now. How much better does a soundtrack sound in TRUE HD? Is it significantly audible? Or is it only something you'll hear with $10,000 amps

I can comment on my modest system and the improvement was easily noticed. All I can say is that it sounds really freakin' good. I remember the first couple of movies I watched kept making me turn my head thinking someone was in my kitchen or something. It was pretty funny.

If you've invested in a BR player & AVR, may as well drop another $20 on an HDMI cable.

Now if someone had a $99 HTIB system from Walmart, I'd probably tell them to invest in better gear instead of HD audio :hand:

[thxpaul]

I can comment on my modest system and the improvement was easily noticed. All I can say is that it sounds really freakin' good. I remember the first couple of movies I watched kept making me turn my head thinking someone was in my kitchen or something. It was pretty funny.

If you've invested in a BR player & AVR, may as well drop another $20 on an HDMI cable.

Now if someone had a $99 HTIB system from Walmart, I'd probably tell them to invest in better gear instead of HD audio :hand:

Gotcha sounds good and thanks for the tips! Will the video quality suffer at all when passing an HDMI cable through my RXV1800?

[L.J.]

Gotcha sounds good and thanks for the tips! Will the video quality suffer at all when passing an HDMI cable through my RXV1800?

The digital signal passes through untouched so it's gonna be a sweet pic. I ran HDMI directly to my display for a bit and I can't see any differences. But I'm not a videophile. To me, a good picture is a good picture.

[f0rge]

Ok that makes sense now. How much better does a soundtrack sound in TRUE HD? Is it significantly audible? Or is it only something you'll hear with $10,000 amps

i'd say it's significant, even on modest equipment

[thxpaul]

i'd say it's significant, even on modest equipment

I got it all hooked up tonight, and I don't know if I'm doing something wrong, but it seems like a quieter soundtrack than the regular dolby digital one. I have to turn my receiver's volume up 3 or 4 dB from where I normally keep it.

This is odd seeing as how one poster described TRUEHD as being louder and more explosive... i find it's the opposite. :(

[f0rge]

hmmm that's weird, it's louder on my setup than standard dolby digital.

but that shouldn't really be a problem, i have to vary my volume a lot depending on the source

[thxpaul]

hmmm that's weird, it's louder on my setup than standard dolby digital.

but that shouldn't really be a problem, i have to vary my volume a lot depending on the source

I've done a little digging and I've come across a few people who also feel that True HD sounds "weak" in a sense. I understand this has to do with a wider dynamic range and all but at times you can barely hear the dialogue - where on the DD soundtrack it's crystal clear.

All in all I found the TrueHD soundtrack a lot less enjoyable.

Also I have a question. The HDMI audio out setting on my BD player can either be set to "auto" or "PCM" - auto is what makes "trueHD" light up on my amp, but what exactly is PCM giving me when I select that instead of auto?

[L.J.]

I got it all hooked up tonight, and I don't know if I'm doing something wrong, but it seems like a quieter soundtrack than the regular dolby digital one. I have to turn my receiver's volume up 3 or 4 dB from where I normally keep it.

This is odd seeing as how one poster described TRUEHD as being louder and more explosive... i find it's the opposite. :(

Your definitely not the first person to say this. "Louder" isn't always better though. I think people hook up there HD gear expecting to get blown out the water with this monstrous loud sound(speaking of monsters, you gotta give Cloverfield a listen...excellent TrueHD track. Crank that up then tell me what you think of TrueHD) , but they're greeted with greater detail, accuracy and dynamic range. Something they're not use to. I remember the first time I got a quality sub, I wasn't too thrilled about the sound because I was use to loud crap slapping me in the face. The smooth accurate, detailed bass just didn't sound right at first. Now I love my sub and could never go back to listening that way again.

Anyways, here's a very excellent post explaining why the HD audio formats are quieter than standard DD/DTS. I gets a little deep but is broken down pretty nice.


Ok, the answer is twofold. I'm going to use PCM as a generic term for PCM, TrueHD, and DTS-HD MA. When decoded, DTS-HD MA and TrueHD end up the same as the PCM master, and most of what I say applies only to PCM. As lossless encoded formats, TrueHD and DTS-HD MA are really just a way to pack PCM to make it take up less space.

First, Dolby and DTS tracks often have their dynamic range compressed to compensate for stuff they're taking out. Dynamic range (measured in dB) is the difference in loudness between the highest sounds and the lowest ones. A small dynamic range means that everything is the same loudness, which means that you're just whacked with a wall of sound with no subtlety or distinct tones. A large dynamic range means that more sounds are present, and you can hear more distinct tones--the wince of a trumpet, the force of the finger on a piano key, etc.

Think of it like a gourmet dinner that has mashed potatoes, beef, pees, and jello. If you eat each one individually, you taste 4 separate things. If you just mash the food all together (or put the jello next to the potatoes), everything blends, and when you take a taste of the resultant amalgamation, you don't taste everything individually, which is too bad if the potatoes or beef is especially good. The original flavors are lost, and you just have a plate of food, not a fine dinner.

This squeezing of the dynamic range is common to all forms of compressed sound, and is actually necessary. Nature allows a very high dynamic range, but they can't encode everything with a small and finite number of codes. So what they do is compress the dynamic range to fit into the smaller window that the codec allows.

PCM also has a limit on its dynamic range as well, but because of the way PCM is done, it is directly determined by the number of bits--96 dB for 16 bit audio, 144 dB for 24 bits (theoretical, circuits don't allow it to go that high). The other lossy codecs don't work that way. You can't get anything useful about the dynamic range out of their "bit depth," which is a misnomer anyway. A "24 bit Dolby Digital" track just means that the original master was 24 bits, since Dolby Digital doesn't have a fixed number of bits per sample, and is a dynamically allocated storage format (channels only get bits when they need it).

When you compress the dynamic range, the overall result is louder sound.

One of them has its dynamic squeezed like an elephant had sat on it. There's no clarity or distinctness in the tones. The other is not as compressed, and you can hear the individual guitar strings resonating and faint crashes of the cymbals.

So why does this happen? Rather than bring the loud sounds down to the quiet ones, they bring the quiet ones up to the loud ones, so the result is that everything in the soundfield is as loud as the loudest thing there. Think of it as a room full of people talking, with one person being a lot louder than the others. Rather than get that one person to talk quieter, everyone else just shouts as well.

That's what you have there, and what you get (not as extreme, of course) with compressed audio. Everything is just in your face.

In addition, PCM tracks are recorded with more headroom than compressed music. Headroom is the amount of space you allow for peaks in volume.

Imagine that you are going to take a truck to pick up some boxes, but don't know ahead of time how many you're going to have. You have some boxes you need to take from your starting point, where you also need to pick a truck. You could take a truck that fits only the boxes you have initially, but then if you get more than that on your second stop, you're in trouble. What you would do is choose a truck that holds far more boxes than you have now, so that when you get to your second stop, you know that you'll have enough room to transport them all.

That's what headroom is. I leave my quiet tones quiet so that when the volume really spikes up, I can fit it all within the range PCM allows without clipping.

Clipping is when the maximum value allowed by your specification is exceeded. If you look at a PCM file, it's nothing more than a bunch of numbers between -1 and 1 (when representing in continuous domain, you have 2^(N-1) values above and below zero, where N is the number of bits. Take the midpoint of 2^N, and make that 0, and sprinkle the higher numbers below 0 and the rest above). If I have a value that ends up as 1.03, I can't write that, so I write the biggest thing I can, which is 1. However, I lose information in that process. In this case, we say that the audio is clipped

When you apply dynamic range compression to a PCM track, this is what happens--the loudest tones try to get louder, but can't, so they just end up a bunch of ones. The quiet ones had room to come up, so they do.

An example. Before compression, say I had like
0.024
0.25
0.23215
0.356
0.565
0.67
0.89
0.87
0.82

(where these are the values for a potion of one second of sound, which contains usually 48000 values, if the sampling rate is 48 kHz).

If I apply a volume boost, I end up with something like
0.224
0.45
0.43215
0.556
0.765
0.87
1.09
1.07
1.02

But PCM can't store a value higher than 1, so it's written to the file as
0.224
0.45
0.43215
0.556
0.765
0.87
1
1
1

The last three values have been clipped. Note that a volume boost ends up causing dynamic range compression, in the end, due to the limitations of PCM.

I don't want to try to record the result after the volume boost, since I end up with clipped sound. It is a better option to record my first set of numbers. That results in an overall quieter track than the second one, since the volume isn't as loud. This is what we mean by PCM having more "headroom"--that first value of 0.024 is awfully small, but we needed to leave it at that so that we'll be able to write the larger values without clipping.

So I hope that explains why PCM/TrueHD/DTS-HD MA tracks sound "quieter." You're actually getting much better sound, and the quietness as compared to Dolby Digital and legacy DTS is a good thing, not a bad one. That's why they invented the volume knob.

[Rich-n-Texas]

Your definitely not the first person to say this. "Louder" isn't always better though. I think people hook up there HD gear expecting to get blown out the water with this monstrous loud sound(speaking of monsters, you gotta give Cloverfield a listen...excellent TrueHD track. Crank that up then tell me what you think of TrueHD) , but they're greeted with greater detail, accuracy and dynamic range. Something they're not use to. I remember the first time I got a quality sub, I wasn't too thrilled about the sound because I was use to loud crap slapping me in the face. The smooth accurate, detailed bass just didn't sound right at first. Now I love my sub and could never go back to listening that way again...
:lol: Go read my post in the PS3 Discussion thread. :yikes: :yikes: :yikes: Gave that alien new meaning!!! It was AWESOME!!!

[thxpaul]

Your definitely not the first person to say this. "Louder" isn't always better though. I think people hook up there HD gear expecting to get blown out the water with this monstrous loud sound(speaking of monsters, you gotta give Cloverfield a listen...excellent TrueHD track. Crank that up then tell me what you think of TrueHD) , but they're greeted with greater detail, accuracy and dynamic range. Something they're not use to. I remember the first time I got a quality sub, I wasn't too thrilled about the sound because I was use to loud crap slapping me in the face. The smooth accurate, detailed bass just didn't sound right at first. Now I love my sub and could never go back to listening that way again.

Anyways, here's a very excellent post explaining why the HD audio formats are quieter than standard DD/DTS. I gets a little deep but is broken down pretty nice.

I actually found that same thread! :) It's very informative - but at the end of the day TrueHD just isn't sounding as good as DD. I find the fact that I can barely hear dialogue to be really annoying. Then I have to crank up the volume to a coma-inducing level to hear what people are saying and then BANG some loud noise rattles my speakers out of nowhere.

Feels like a step down to me. I realize what it is and why. Just a personal preference perhaps.

Oh and do you know the difference between PCM and Auto?
The HDMI audio out setting on my BD player can either be set to "auto" or "PCM" - auto is what makes "trueHD" light up on my amp, but what exactly is PCM giving me when I select that instead of auto?

I don't really understand the difference.

[L.J.]

I actually found that same thread! :) It's very informative - but at the end of the day TrueHD just isn't sounding as good as DD. I find the fact that I can barely hear dialogue to be really annoying. Then I have to crank up the volume to a coma-inducing level to hear what people are saying and then BANG some loud noise rattles my speakers out of nowhere.

Could be the recording. I've heard plenty of DVD's that are notorious for that. Lady in the Water comes to mind. Does it on the DVD & BR version


Feels like a step down to me. I realize what it is and why. Just a personal preference perhaps.

I'd listen to a few more tracks before throwing it completely out the window. If you still don't like it, I'll take it off your hands and I'm willing to pay for the shipping :biggrin5:


Oh and do you know the difference between PCM and Auto?
The HDMI audio out setting on my BD player can either be set to "auto" or "PCM" - auto is what makes "trueHD" light up on my amp, but what exactly is PCM giving me when I select that instead of auto?

I don't really understand the difference.

Auto has your player set to bitstream everything to your AVR for decoding.

PCM has your player set to decode everything internally and send the decoded signal to your AVR via analog out or HDMI v1.1 or up. Basically, a person with an older AVR would set the player to PCM and use the analog outs or older version of HDMI.

Since you have a newer AVR, your cool using auto.

[thxpaul]

Could be the recording. I've heard plenty of DVD's that are notorious for that. Lady in the Water comes to mind. Does it on the DVD & BR version



I'd listen to a few more tracks before throwing it completely out the window. If you still don't like it, I'll take it off your hands and I'm willing to pay for the shipping :biggrin5:



Auto has your player set to bitstream everything to your AVR for decoding.

PCM has your player set to decode everything internally and send the decoded signal to your AVR via analog out or HDMI v1.1 or up. Basically, a person with an older AVR would set the player to PCM and use the analog outs or older version of HDMI.

Since you have a newer AVR, your cool using auto.

Thanks for the help. What are some other really good TrueHD soundtracks I can check out? "Ill try to grab cloverfield tonight. Any others you can suggest?

[L.J.]

Thanks for the help. What are some other really good TrueHD soundtracks I can check out? "Ill try to grab cloverfield tonight. Any others you can suggest?

Well your not limited to just TrueHD. Your player can handle MPCM as well. Alot of Disney titles are PCM and most are high quality. Try Pirates or even their animation is really good. I was shocked at how good Enchanted looked and sounded. Ratatouille & Cars are reference matl.

Sony has alot of PCM & TrueHD titles. Spiderman is good. You can also try Casino Royale, Apocalypto, Black Hawk Down, Batman Begins.

[thxpaul]

Well your not limited to just TrueHD. Your player can handle MPCM as well. Alot of Disney titles are PCM and most are high quality. Try Pirates or even their animation is really good. I was shocked at how good Enchanted looked and sounded. Ratatouille & Cars are reference matl.

Sony has alot of PCM & TrueHD titles. Spiderman is good. You can also try Casino Royale, Apocalypto, Black Hawk Down, Batman Begins.

I bought Cloverfield and the TrueHD soundtrack on this is better than the one on Batman Begins. But it still seems "off" to me... dialogue is TOO low IMO. It's supposed to sound like real life and yet the voices sound much quieter than people do when they're talking in front of you...

i dunno maybe I just have to retrain my ears :)

[L.J.]

Did you use the Yammie mic to calibrate your system (levels, distances)?

Do you have the EQ engaged?

Do you own a SPL meter to check your levels?

Perhaps your center is set a couple db lower than the rest of your system.

[thxpaul]

I calibrated, didn't have much of an effect on the overall sound...

No EQ, just the yammies decoder and the bitstream signal.

I don't own a meter. The center channel is set at .5dB so maybe I need to up the volume on that a little and save it to a setting I use when i watch TrueHD soundtracks?

[thxpaul]

Oh and also the Cloverfield TrueHD soundtrack is the ONLY english soundtrack on the disc... can we expect to see more and more bluray discs being released without a regular DD track?

[L.J.]

Oh and also the Cloverfield TrueHD soundtrack is the ONLY english soundtrack on the disc... can we expect to see more and more bluray discs being released without a regular DD track?

You'll still get DD. TrueHD has a "core" DD track that is compatible with standard AVRs.

I'm not sure how your center is positioned, but you want it to be as close to ear level as possible. I know this isn't always practical because this is where most of us put our TV, so you can try slightly tilting your center toward the sweet spot.

[thxpaul]

You'll still get DD. TrueHD has a "core" DD track that is compatible with standard AVRs.

I'm not sure how your center is positioned, but you want it to be as close to ear level as possible. I know this isn't always practical because this is where most of us put our TV, so you can try slightly tilting your center toward the sweet spot.

I see. Is there any way to access that "core" DD track if I'm connected through my AVR via HDMI?

A setting on my player perhaps? Or the receiver?

Because like... if I can select between the two on the disc menu then it's fine. But if there's only TrueHD then my AVR defaults to this format obviously.

[Rich-n-Texas]

38 posts... 38 questions. You DO have an owners manual right?

[L.J.]

I see. Is there any way to access that "core" DD track if I'm connected through my AVR via HDMI?

A setting on my player perhaps? Or the receiver?

Because like... if I can select between the two on the disc menu then it's fine. But if there's only TrueHD then my AVR defaults to this format obviously.

You gotta have a optical/coax connection from your player to AVR and select that under "audio select" on your AVR. I can toggle between HDMI -> Optical -> Analog on my Yammie using the audio select button. And your optical/coax needs to be on the correct source input(DVD, CD, DTV) of course.

[thxpaul]

38 posts... 38 questions. You DO have an owners manual right?

Hey tex' chill out and have a beer.

Nobody is forced to answer anything. Yeah I could spend half an hour sifting through a cryptic manual and maybe I'd find my answer or I could try my luck here and perhaps someone might know the answer right off the bat.

And if people don't know then hey, I'll do some sifting just for you!

[thxpaul]

You gotta have a optical/coax connection from your player to AVR and select that under "audio select" on your AVR. I can toggle between HDMI -> Optical -> Analog on my Yammie using the audio select button. And your optical/coax needs to be on the correct source input(DVD, CD, DTV) of course.

Ahh makes sense I should leave them both plugged in then. Yeah my yammie has the auto/coax thing to select the input as well. Thanks very much!

[pixelthis]

38 posts... 38 questions. You DO have an owners manual right?

YOU berating someone for not reading an owners manual?
Pardon the expression but THATS RICH ( ROFL)

The only thing you use an owners manual for:1:

[GMichael]

You guys play nice. Don't make me use me belt.

[johnny p]

OP.... don't run out and pay $20 for an HDMI cable anyways..... get them at Monoprice or Bluejeans Cable etc... for $5 each

there is another site, can't recall it off the top of my head though.

[thxpaul]

OP.... don't run out and pay $20 for an HDMI cable anyways..... get them at Monoprice or Bluejeans Cable etc... for $5 each

there is another site, can't recall it off the top of my head though.

I bought a Rocketfish one for $40. I feel ripped off. It still blows my mind that there are 2m monster cables for over $300 CAD.

A digital signal is a digital signal isn't it? If the signal was interrupted by a poor cable, wouldn't the picture not show at all? The tv either gets it or it doesn't correct? Or am I wrong?

I understand the construction of Monster cable products is first rate but I mean after I've plugged my stuff in... it's just sitting behind my rack, why do I need BOMBproof cables? I'm not driving a tank over them on a daily basis....

Maybe I'm wrong but that's just the way I've come to see it.

[Sir Terrence the Terrible]

Ok, the answer is twofold. I'm going to use PCM as a generic term for PCM, TrueHD, and DTS-HD MA. When decoded, DTS-HD MA and TrueHD end up the same as the PCM master, and most of what I say applies only to PCM. As lossless encoded formats, TrueHD and DTS-HD MA are really just a way to pack PCM to make it take up less space.

Accurate


First, Dolby and DTS tracks often have their dynamic range compressed to compensate for stuff they're taking out. Dynamic range (measured in dB) is the difference in loudness between the highest sounds and the lowest ones. A small dynamic range means that everything is the same loudness, which means that you're just whacked with a wall of sound with no subtlety or distinct tones. A large dynamic range means that more sounds are present, and you can hear more distinct tones--the wince of a trumpet, the force of the finger on a piano key, etc.

This information is bogus. Neither Dolby nor Dts have their dynamic range compressed. Both are capable of a dynamic range of about 120db, which is far greater than you and I can stand. Dolby uses a sophisticated algorythm to remove data that is not heard, and Dts does as well. That is the only compression going on in these codecs. Removing the data does not effect dynamic range at all.


Think of it like a gourmet dinner that has mashed potatoes, beef, pees, and jello. If you eat each one individually, you taste 4 separate things. If you just mash the food all together (or put the jello next to the potatoes), everything blends, and when you take a taste of the resultant amalgamation, you don't taste everything individually, which is too bad if the potatoes or beef is especially good. The original flavors are lost, and you just have a plate of food, not a fine dinner.

Very poor analogy. It does not discribe the process at all.


This squeezing of the dynamic range is common to all forms of compressed sound, and is actually necessary. Nature allows a very high dynamic range, but they can't encode everything with a small and finite number of codes. So what they do is compress the dynamic range to fit into the smaller window that the codec allows.

Completely incorrect. He is mixing the reduction of data with the reduction of dynamic range. Two distinctly different processes.


PCM also has a limit on its dynamic range as well, but because of the way PCM is done, it is directly determined by the number of bits--96 dB for 16 bit audio, 144 dB for 24 bits (theoretical, circuits don't allow it to go that high). The other lossy codecs don't work that way. You can't get anything useful about the dynamic range out of their "bit depth," which is a misnomer anyway. A "24 bit Dolby Digital" track just means that the original master was 24 bits, since Dolby Digital doesn't have a fixed number of bits per sample, and is a dynamically allocated storage format (channels only get bits when they need it).

Another wrong statement. He does not seem to understand that Dts and DD both reduce the data, but re-encode it at 20bits for Dts, and 18bits for DD when you account for the average dialog normalization value. So a Dts track that is 24/48khz actually has in theory the full 144db of dynamic range that 24bit PCM does. While DD does not have have a fixed number of bits for its audio thanks to the global bit allocation process in its algorythm. But that does not effect dynamic range, but it does lead to bit starvation which can degrade audio quality.


When you compress the dynamic range, the overall result is louder sound.

One of them has its dynamic squeezed like an elephant had sat on it. There's no clarity or distinctness in the tones. The other is not as compressed, and you can hear the individual guitar strings resonating and faint crashes of the cymbals.

Over and over again this guy is mixing up data compression with dynamic range compression. The two couldn't be more different. DD as data compressed as it is can still easily encode a film track, but like any aggressive encoder their are losses in quality as a result of the compression. You are not going to get something for nothing here.


So why does this happen? Rather than bring the loud sounds down to the quiet ones, they bring the quiet ones up to the loud ones, so the result is that everything in the soundfield is as loud as the loudest thing there. Think of it as a room full of people talking, with one person being a lot louder than the others. Rather than get that one person to talk quieter, everyone else just shouts as well.

That's what you have there, and what you get (not as extreme, of course) with compressed audio. Everything is just in your face.

Still mixing things up here.


In addition, PCM tracks are recorded with more headroom than compressed music. Headroom is the amount of space you allow for peaks in volume.

Wrong again. 0 reference is 0 reference in digital audio. There is no more headroom in a PCM track than there is in a DD or Dts track. Since DD and Dts encodes are sourced directly from PCM, what he says is basically impossible.


Imagine that you are going to take a truck to pick up some boxes, but don't know ahead of time how many you're going to have. You have some boxes you need to take from your starting point, where you also need to pick a truck. You could take a truck that fits only the boxes you have initially, but then if you get more than that on your second stop, you're in trouble. What you would do is choose a truck that holds far more boxes than you have now, so that when you get to your second stop, you know that you'll have enough room to transport them all.

That's what headroom is. I leave my quiet tones quiet so that when the volume really spikes up, I can fit it all within the range PCM allows without clipping.

Great analogy, but it does not describe what is happening with either legacy codec.


Clipping is when the maximum value allowed by your specification is exceeded. If you look at a PCM file, it's nothing more than a bunch of numbers between -1 and 1 (when representing in continuous domain, you have 2^(N-1) values above and below zero, where N is the number of bits. Take the midpoint of 2^N, and make that 0, and sprinkle the higher numbers below 0 and the rest above). If I have a value that ends up as 1.03, I can't write that, so I write the biggest thing I can, which is 1. However, I lose information in that process. In this case, we say that the audio is clipped

When you apply dynamic range compression to a PCM track, this is what happens--the loudest tones try to get louder, but can't, so they just end up a bunch of ones. The quiet ones had room to come up, so they do.

Wrong again! Dynamic range compression does not send the audio closer to 0db reference, at all. If anything it may pull it back from the level as compression makes the loudest sounds softer(pushing away from 0db, and softest sounds a little louder. It decreases the overall dynamic range. Now you could raise the average level of everthing upwards, while compressing the dynamic range, and that will send some peaks into overload, but no engineer worth his salt would do such a thing, because its mind numbing over a long period of time.


The last three values have been clipped. Note that a volume boost ends up causing dynamic range compression, in the end, due to the limitations of PCM.

Now he is talking about the effects on analog signals, because digital signals don't compress when the volume gets turned up, they clip.


I don't want to try to record the result after the volume boost, since I end up with clipped sound. It is a better option to record my first set of numbers. That results in an overall quieter track than the second one, since the volume isn't as loud. This is what we mean by PCM having more "headroom"--that first value of 0.024 is awfully small, but we needed to leave it at that so that we'll be able to write the larger values without clipping.

Still not right. He is not taking in to consideration that the voltage of the HDMI connection, and the coaxial and toslink connection is quite different, so they effect the overall loudness of the signal even before your volume knob does. What he describes as a audible change would not even be audible under most conditions.


So I hope that explains why PCM/TrueHD/DTS-HD MA tracks sound "quieter." You're actually getting much better sound, and the quietness as compared to Dolby Digital and legacy DTS is a good thing, not a bad one. That's why they invented the volume knob.

This is perhaps one of the worst violations of accuracy I have ever seen regarding the loudness difference between the new audio codecs, and the older legacy ones. He could have saved all of this blather and just said the newer codecs sound softer because they were mastered softer, and he would have been alot more accurate than the crap he posted.

[thxpaul]

Accurate



This information is bogus. Neither Dolby nor Dts have their dynamic range compressed. Both are capable of a dynamic range of about 120db, which is far greater than you and I can stand. Dolby uses a sophisticated algorythm to remove data that is not heard, and Dts does as well. That is the only compression going on in these codecs. Removing the data does not effect dynamic range at all.



Very poor analogy. It does not discribe the process at all.



Completely incorrect. He is mixing the reduction of data with the reduction of dynamic range. Two distinctly different processes.



Another wrong statement. He does not seem to understand that Dts and DD both reduce the data, but re-encode it at 20bits for Dts, and 18bits for DD when you account for the average dialog normalization value. So a Dts track that is 24/48khz actually has in theory the full 144db of dynamic range that 24bit PCM does. While DD does not have have a fixed number of bits for its audio thanks to the global bit allocation process in its algorythm. But that does not effect dynamic range, but it does lead to bit starvation which can degrade audio quality.



Over and over again this guy is mixing up data compression with dynamic range compression. The two couldn't be more different. DD as data compressed as it is can still easily encode a film track, but like any aggressive encoder their are losses in quality as a result of the compression. You are not going to get something for nothing here.



Still mixing things up here.



Wrong again. 0 reference is 0 reference in digital audio. There is no more headroom in a PCM track than there is in a DD or Dts track. Since DD and Dts encodes are sourced directly from PCM, what he says is basically impossible.



Great analogy, but it does not describe what is happening with either legacy codec.



Wrong again! Dynamic range compression does not send the audio closer to 0db reference, at all. If anything it may pull it back from the level as compression makes the loudest sounds softer(pushing away from 0db, and softest sounds a little louder. It decreases the overall dynamic range. Now you could raise the average level of everthing upwards, while compressing the dynamic range, and that will send some peaks into overload, but no engineer worth his salt would do such a thing, because its mind numbing over a long period of time.



Now he is talking about the effects on analog signals, because digital signals don't compress when the volume gets turned up, they clip.



Still not right. He is not taking in to consideration that the voltage of the HDMI connection, and the coaxial and toslink connection is quite different, so they effect the overall loudness of the signal even before your volume knob does. What he describes as a audible change would not even be audible under most conditions.



This is perhaps one of the worst violations of accuracy I have ever seen regarding the loudness difference between the new audio codecs, and the older legacy ones. He could have saved all of this blather and just said the newer codecs sound softer because they were mastered softer, and he would have been alot more accurate than the crap he posted.

Wow F'ing RIPPED apart!

Anyways I've been listening to more and more of the TrueHD audio and I see how it's a little more 'involving' if I can use that term in the sense that you feel a little more immersed because (to me at least) it seems there's more emphasis put on the smaller clicks and clacks - which I suppose is realistic in a sense.

What I don't like - and I don't care what anybody says - is that the dialogue sounds WAY too low for a "realistic" feel. When people talk in front of me they don't sound muddy or whisper quiet at times while a door closing 50 feet away is heard with crystal clarity.

Let me just remind everybody that with a dts or DD track - I never get this feeling so it's not as if my speakers are just muddy sounding or my amp can't drive them...

But aside from that dialogue issue the tracks sound cool. Maybe I'll just crank up the centre channel speaker another dB or two and call it that.

OH and in case pixelthis reads this - I checked to see if my centre speaker was producing sound with TrueHD and it is so it's not the issue you're having I guess.

[anamorphic96]

Sounds like your speakers are not level matched. You might want to go out and buy an SPL meter at Radio Shack and calibrate all your speakers to 75db. They only cost 35.00.

[Woochifer]

Wow F'ing RIPPED apart!

Anyways I've been listening to more and more of the TrueHD audio and I see how it's a little more 'involving' if I can use that term in the sense that you feel a little more immersed because (to me at least) it seems there's more emphasis put on the smaller clicks and clacks - which I suppose is realistic in a sense.

What I don't like - and I don't care what anybody says - is that the dialogue sounds WAY too low for a "realistic" feel. When people talk in front of me they don't sound muddy or whisper quiet at times while a door closing 50 feet away is heard with crystal clarity.

Let me just remind everybody that with a dts or DD track - I never get this feeling so it's not as if my speakers are just muddy sounding or my amp can't drive them...

But aside from that dialogue issue the tracks sound cool. Maybe I'll just crank up the centre channel speaker another dB or two and call it that.

Sounds more like you need a SPL meter to calibrate the center speaker and try different alignments. (Digital Video Essentials is now available on Blu-ray, and should have the appropriate test tones on it) If this dialog issue remains a constant, then the issue has has less to do with the soundtrack or the audio format, and more to do with your system setup. If you've never done a level check with your speakers, then you need to do that first before you go blaming the audio format or speakers or amp.

[thxpaul]

Sounds like your speakers are not level matched. You might want to go out and buy an SPL meter at Radio Shack and calibrate all your speakers to 75db. They only cost 35.00.

Yeah I've never used one before maybe I'll pick one up. Worth a shot I guess. Thanks dudes.

[L.J.]

Accurate



This information is bogus. Neither Dolby nor Dts have their dynamic range compressed. Both are capable of a dynamic range of about 120db, which is far greater than you and I can stand. Dolby uses a sophisticated algorythm to remove data that is not heard, and Dts does as well. That is the only compression going on in these codecs. Removing the data does not effect dynamic range at all.



Very poor analogy. It does not discribe the process at all.



Completely incorrect. He is mixing the reduction of data with the reduction of dynamic range. Two distinctly different processes.



Another wrong statement. He does not seem to understand that Dts and DD both reduce the data, but re-encode it at 20bits for Dts, and 18bits for DD when you account for the average dialog normalization value. So a Dts track that is 24/48khz actually has in theory the full 144db of dynamic range that 24bit PCM does. While DD does not have have a fixed number of bits for its audio thanks to the global bit allocation process in its algorythm. But that does not effect dynamic range, but it does lead to bit starvation which can degrade audio quality.



Over and over again this guy is mixing up data compression with dynamic range compression. The two couldn't be more different. DD as data compressed as it is can still easily encode a film track, but like any aggressive encoder their are losses in quality as a result of the compression. You are not going to get something for nothing here.



Still mixing things up here.



Wrong again. 0 reference is 0 reference in digital audio. There is no more headroom in a PCM track than there is in a DD or Dts track. Since DD and Dts encodes are sourced directly from PCM, what he says is basically impossible.



Great analogy, but it does not describe what is happening with either legacy codec.



Wrong again! Dynamic range compression does not send the audio closer to 0db reference, at all. If anything it may pull it back from the level as compression makes the loudest sounds softer(pushing away from 0db, and softest sounds a little louder. It decreases the overall dynamic range. Now you could raise the average level of everthing upwards, while compressing the dynamic range, and that will send some peaks into overload, but no engineer worth his salt would do such a thing, because its mind numbing over a long period of time.



Now he is talking about the effects on analog signals, because digital signals don't compress when the volume gets turned up, they clip.



Still not right. He is not taking in to consideration that the voltage of the HDMI connection, and the coaxial and toslink connection is quite different, so they effect the overall loudness of the signal even before your volume knob does. What he describes as a audible change would not even be audible under most conditions.



This is perhaps one of the worst violations of accuracy I have ever seen regarding the loudness difference between the new audio codecs, and the older legacy ones. He could have saved all of this blather and just said the newer codecs sound softer because they were mastered softer, and he would have been alot more accurate than the crap he posted.

Doh! That's what I get for using google to search out an answer. I actually ran across the "compressed dynamic range" on a couple of different forums. I guess there's alot of confusion out there. I'll have to be more careful in the future. Wouldn't want to be spreading false info. Kinda too deep for me. I like to just play a BR and call it a day. Thanks for breaking down though brotha. I was wondering when you were gonna pop in here.

Now I'll have to go back and read your post 50 times until it makes sense to me :D

[Woochifer]

Doh! That's what I get for using google to search out an answer. I actually ran across the "compressed dynamic range" on a couple of different forums. I guess there's alot of confusion out there. I'll have to be more careful in the future. Wouldn't want to be spreading false info. Kinda too deep for me. I like to just play a BR and call it a day. Thanks for breaking down though brotha. I was wondering when you were gonna pop in here.

Now I'll have to go back and read your post 50 times until it makes sense to me :D

Yeah, it seems like a fairly common mixup between dynamic range compression and data compression. All the time, people complain about how MP3s sound "compressed" when the lossy data compression doesn't actually affect the dynamic range. But, rather the data compression affects the sound quality by eliminating a lot of the complexity and subtlety. That's why Dolby Digital can sound abrupt and blunt with complex high pitched sounds like a cymbal or a muted trumpet.

On the flip side, a CD can sound "compressed" if the dynamic range gets reduced. This is now common practice with CD mastering in order to have them sound louder. But, all of this occurs within a PCM audio track whose data stream remains uncompressed. In other words, whether the source's dynamic range is heavily compressed or not, the data stream on a CD maintains the exact same data rate because the CD's PCM audio is by definition an uncompressed format.

[pixelthis]

but the most important fact in this whole disscussion is
that its moot, kinda like two bald men fighting over a comb.
Because you wont be able to tell the difference.
A few golden ears will be able to differentiate between the new
lossless formats and the old "lossy" ones, but most wont even notice.
AND THE DIFF BETWEEN ALL OF THE NEW "LOSSLESS"
formats?
Lassie wont be able to tell, yso you sure wont be able to:1: