high end Dolby AC-3 vs. avg. Dolby TrueHD processor [Archive] - Audio & Video Forums

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Rev2Liv
02-18-2008, 12:49 AM
A surround sound processor is the sum of all individual parts. Thus quality of both analog and digital sections play a pivotal role in sound.

How does a Proceed AVP Dolby Digital surround processor compare to a middle of the road Dolby TrueHD setup? Am I better off using the 5.1 TrueHD analog bypass or letting the AVP decode AC-3 surround material?

In it's day, the Proceed AVP sold for close to $5000 and featured balanced analog section (Left,center,right channels) and discrete d/a converters for surrround channels. The analog section still beats the pants off any mass market Japanese gear.

I'm wondering if uncompressed 24bit/96hz Dolby True HD will beat 10 year old AC-3? Should I feed the analog 5.1 Dolby TrueHD from a Blu-Ray player through the analog bypass?

Moving from Dolby Pro-Logic to Dolby Digital AC-3 was a quantum leap back in 1997. I don't expect Dolby TrueHD to be more evolutionary rather than revolutionary.

Can someone here please provide anecdotal evidence supporting the difference between Dolby Digital and Dolby TrueHD? Thanks!

Sir Terrence the Terrible
02-18-2008, 08:15 AM
A surround sound processor is the sum of all individual parts. Thus quality of both analog and digital sections play a pivotal role in sound.

How does a Proceed AVP Dolby Digital surround processor compare to a middle of the road Dolby TrueHD setup? Am I better off using the 5.1 TrueHD analog bypass or letting the AVP decode AC-3 surround material?

In it's day, the Proceed AVP sold for close to $5000 and featured balanced analog section (Left,center,right channels) and discrete d/a converters for surrround channels. The analog section still beats the pants off any mass market Japanese gear.

I'm wondering if uncompressed 24bit/96hz Dolby True HD will beat 10 year old AC-3? Should I feed the analog 5.1 Dolby TrueHD from a Blu-Ray player through the analog bypass?

Moving from Dolby Pro-Logic to Dolby Digital AC-3 was a quantum leap back in 1997. I don't expect Dolby TrueHD to be more evolutionary rather than revolutionary.

Can someone here please provide anecdotal evidence supporting the difference between Dolby Digital and Dolby TrueHD? Thanks!

I would not recommend investing in yesterdays technology, no matter how good it is. Dolby Digital no matter what processor you put it in, will sound the same. The Dolby Digital algorythm is the same whether it is in a reciever, or a high end processor like the AVP. It is a lossy codec only capable in the AVP of 640kbps. That is not enough bits to compete with a lossless codec like DTHD. If the AVP could process Dolby Digital plus, you would be about as close to lossless as a lossy codec would allow.

DTHD is a bit for bit copy of the master tape from the dubbing stage. This is as close as hometheater has ever come to these tapes, and going forward this will probably be one of the codecs of choice for the new fomats. Even a run of the mill receiver can accurately pass a DTHD bitstream, so this is the direction I would go.

If you want access to the DTHD stream and your processor is not HDMI compatible, then the analog 5.1 are the only way to go. Just use the 5.1 analog outs from the bluray player to the 5.1 analog ins on the reciever or processors. The player will do all of the decoding and post processing.

musicman1999
02-18-2008, 09:45 AM
While i disagree with Sir T that DD will sound the same no matter what processor you feed it to, he is correct that the new formats are clearly superior.I have an Anthem AVM-30 and when i feed it uncompressed PCM from my Sony Bluray player the sound is clearly better than Dolby Digital or DTS, even when fed from my Sim Audio dvd player and it is the best DVD player i have ever seen or heard.

bill

Rev2Liv
02-18-2008, 10:29 PM
Thanks for the help guys. From what I understand, Dolby TrueHD is less complicated than AC-3 because it uses lossless compression. Thus, less sophisticated equipment is needed to playback 5.1 channels.

The main reason I would want a Dolby TrueHD surround processor rather than use the 5.1 analog bypass is to be able to handle all adjustments in the digital domain. Things such as crossover frequencies, equalization are best handled in the digital domain. Using a 5.1ch bypass, the surround processor would first need to do an A/D conversion, process and then finally D/A again for any adjustments besides volume.

Why are very few vendors offering Dolby TrueHD hardware? 2008 appears to be the year where everything comes together. Blu-Ray won, HDMI 1.3 appears to be a final spec and RCA's will be around for at least another 10 years.

pixelthis
02-18-2008, 11:50 PM
Thanks for the help guys. From what I understand, Dolby TrueHD is less complicated than AC-3 because it uses lossless compression. Thus, less sophisticated equipment is needed to playback 5.1 channels.

The main reason I would want a Dolby TrueHD surround processor rather than use the 5.1 analog bypass is to be able to handle all adjustments in the digital domain. Things such as crossover frequencies, equalization are best handled in the digital domain. Using a 5.1ch bypass, the surround processor would first need to do an A/D conversion, process and then finally D/A again for any adjustments besides volume.

Why are very few vendors offering Dolby TrueHD hardware? 2008 appears to be the year where everything comes together. Blu-Ray won, HDMI 1.3 appears to be a final spec and RCA's will be around for at least another 10 years.

Sir talky is as usual is wrong, all procs decoding ac3 are basically the same but how they do it is worlds apart.
My yamaha beat the pants off of a technics decoder I had.
As for "truehd" and other vaporware why worry about it?
THE MAIN THING TO WORRY ABOUT is the quality of the amps, and you wont
beat the proceed, dont worry about anything else in a receiver until the dust settles.
As for adjustments there will be plenty on the player.
You are right, vollume is the only adjustment your receiver will do (your surround proc will be completly left out) but vollume is all you need, the player will have everything else.
Every DVD player I HAVE HAD HAS ADJUSTMENTS for the onboard DD,
dont see why Blu players will be any different.
THE ONLY REASON you need to even consider your proc in the proceed is for DD from
SD DVDs, the rest will come from the player into your 5.1 and straight out to your speakers.
Now if you want to you can get rid of a good device, get a "new" one with DD true HD ,
hdmi 1.3, etc (when and if they come out) and then when THATS obsolete in a year
shell out another few grand for another one.
You can chase vaporware until you're broke.
My receiver is running on four years old, has COMPONENT switching, was state of the art
when I bought it.
My upconverting DVD player has DVI, was state of the art two years ago when I bought IT.
My tv HAS hdmi (first version) and yup, you guessed it, state of the "art" a year ago.
I have a great receiver with great amps and 7.1 in, and thats ALL I need.
Anything "new" in this industry gone crazy will be on a player or I wont bother.
These fools have gone from component to DVI to HDMI to hdmi 1.3...
IN FOUR YEARS. Totally insane.
And if you want to chase this mess be my guest. I AM WAITING.
And waiting...:1:

Rev2Liv
02-20-2008, 11:16 AM
Everyone has given me excellent insight. I agree with Sir T. in that the AC-3 codec is standard, but each vendor implements it differently. All vendors rely mostly on Motorola or TI DSP's to decode codec's. An Analog Devices SHARC DSP costs many times more than a Motorola. I don't believe in proprietary DSP algorithms like Lexicon Logic7, but they are responsible for a companies "signature" sound.

In the digital domain, DAC's also play a large role in sound output. The highest quality 24bit 96khz Burr-Brown DAC's cost much more than average parts but is more accurate and the difference can be easily measured using test equipment.

In the analog domain, differences IMO are much more noticeable. High quality analog stage is expensive.....period. Between balanced inputs/outputs, high quality op-amps and clean circuit design, tooling, design and manufacturing costs rise considerably.

Last, an isolated power supply and dual discrete transformers for analog and digital stage further help sound quality.

I think my best bet is to stick with 5.1ch analog bypass for TrueHD as pixelthis has recommended. TrueHD appears to be in the early adopter phase on the hardware side. I'm going to wait for standards across the board before throwing down lots of cash on a new surround processor.

I'm still surprised that the big boys like Lexicon,Theta and Krell haven't come out with a TrueHD decoder.

pixelthis
02-21-2008, 02:57 PM
Everyone has given me excellent insight. I agree with Sir T. in that the AC-3 codec is standard, but each vendor implements it differently. All vendors rely mostly on Motorola or TI DSP's to decode codec's. An Analog Devices SHARC DSP costs many times more than a Motorola. I don't believe in proprietary DSP algorithms like Lexicon Logic7, but they are responsible for a companies "signature" sound.

In the digital domain, DAC's also play a large role in sound output. The highest quality 24bit 96khz Burr-Brown DAC's cost much more than average parts but is more accurate and the difference can be easily measured using test equipment.

In the analog domain, differences IMO are much more noticeable. High quality analog stage is expensive.....period. Between balanced inputs/outputs, high quality op-amps and clean circuit design, tooling, design and manufacturing costs rise considerably.

Last, an isolated power supply and dual discrete transformers for analog and digital stage further help sound quality.

I think my best bet is to stick with 5.1ch analog bypass for TrueHD as pixelthis has recommended. TrueHD appears to be in the early adopter phase on the hardware side. I'm going to wait for standards across the board before throwing down lots of cash on a new surround processor.

I'm still surprised that the big boys like Lexicon,Theta and Krell haven't come out with a TrueHD decoder.

NOT REALLY.
If you notice most lines of receivers are the same basic device, with the same basic chassis, power and features are added as you go up the "line".
This saves cash
THE bLU BOYS haven't even finished finalizing their format, no one is going to come out with anything until things stabilize a bit.
No one wants to get stuck with an obsolete piece of gear.

Go to outlaw.com and check out their nice prepro, for example.
It has DVI switching.
Why? Because the nimrods running this industry have changed video connectors 3 or 4 times in about 4 years. How does a company base a business decision on such nonsense? ESPECIALLY A SMALL ONE?
They wait, thats what they do.
My receiver cost 1200 bucks, has wideband video switching and upconversion
and its just about obsolete, because it has component video switching

Not gonna get caught like that again, neither are the "big boys":1:

Rev2Liv
02-22-2008, 09:48 PM
NOT REALLY.
If you notice most lines of receivers are the same basic device, with the same basic chassis, power and features are added as you go up the "line".
This saves cash
THE bLU BOYS haven't even finished finalizing their format, no one is going to come out with anything until things stabilize a bit.
No one wants to get stuck with an obsolete piece of gear.

Go to outlaw.com and check out their nice prepro, for example.
It has DVI switching.
Why? Because the nimrods running this industry have changed video connectors 3 or 4 times in about 4 years. How does a company base a business decision on such nonsense? ESPECIALLY A SMALL ONE?
They wait, thats what they do.
My receiver cost 1200 bucks, has wideband video switching and upconversion
and its just about obsolete, because it has component video switching

Not gonna get caught like that again, neither are the "big boys":1:

The lack of standards is deplorable and mind numbing when you consider what kind of crap the computer industry has been through. I understand that RCA coaxial digital out and Toslink lack the necessary bandwidth to pass through Dolby TrueHD. Why not beef up Those two standards using the same connector to make it backward compatible? I vote for Toslink 2 and RCA coax digital out version 2.0.

I really hate HDMI. weaving audio/video into the same connector/cable really limits my wiring options.If the a/v industry wants to get cute, they should take a lesson from the Playstation and use one port, but sell different cables that terminate into separate connectors. Apple in early 2000 tried to get cute with their ADC monitor cable which wrapped power, USB, and video in one cable using one connector. It was an elegant solution, but not practical at all. Today, with their monitors, they wrap all the cables in one bundle, but that bundle terminates into separate USB2, FireWire, video and power.

Will HDMI 1.3b and Blu-Ray profile 2.0 be the standard for the next ten years?

pixelthis
02-25-2008, 03:52 AM
The lack of standards is deplorable and mind numbing when you consider what kind of crap the computer industry has been through. I understand that RCA coaxial digital out and Toslink lack the necessary bandwidth to pass through Dolby TrueHD. Why not beef up Those two standards using the same connector to make it backward compatible? I vote for Toslink 2 and RCA coax digital out version 2.0.

I really hate HDMI. weaving audio/video into the same connector/cable really limits my wiring options.If the a/v industry wants to get cute, they should take a lesson from the Playstation and use one port, but sell different cables that terminate into separate connectors. Apple in early 2000 tried to get cute with their ADC monitor cable which wrapped power, USB, and video in one cable using one connector. It was an elegant solution, but not practical at all. Today, with their monitors, they wrap all the cables in one bundle, but that bundle terminates into separate USB2, FireWire, video and power.

Will HDMI 1.3b and Blu-Ray profile 2.0 be the standard for the next ten years?

Its doubtfull.
I can't beleive that a rca coax cant carry true HD, it can carry composite video, after all.
This format must be a bandwidth hog if thats true.
I love the current HDMI, use it when component would be more convienent, but find that it doesnt limit my options at all, theres always a coax or toslink for audio

Sir Terrence the Terrible
02-25-2008, 02:03 PM
Sir talky is as usual is wrong, all procs decoding ac3 are basically the same but how they do it is worlds apart.
My yamaha beat the pants off of a technics decoder I had.
As for "truehd" and other vaporware why worry about it?
THE MAIN THING TO WORRY ABOUT is the quality of the amps, and you wont
beat the proceed, dont worry about anything else in a receiver until the dust settles.
As for adjustments there will be plenty on the player.
You are right, vollume is the only adjustment your receiver will do (your surround proc will be completly left out) but vollume is all you need, the player will have everything else.
Every DVD player I HAVE HAD HAS ADJUSTMENTS for the onboard DD,
dont see why Blu players will be any different.
THE ONLY REASON you need to even consider your proc in the proceed is for DD from
SD DVDs, the rest will come from the player into your 5.1 and straight out to your speakers.
Now if you want to you can get rid of a good device, get a "new" one with DD true HD ,
hdmi 1.3, etc (when and if they come out) and then when THATS obsolete in a year
shell out another few grand for another one.
You can chase vaporware until you're broke.
My receiver is running on four years old, has COMPONENT switching, was state of the art
when I bought it.
My upconverting DVD player has DVI, was state of the art two years ago when I bought IT.
My tv HAS hdmi (first version) and yup, you guessed it, state of the "art" a year ago.
I have a great receiver with great amps and 7.1 in, and thats ALL I need.
Anything "new" in this industry gone crazy will be on a player or I wont bother.
These fools have gone from component to DVI to HDMI to hdmi 1.3...
IN FOUR YEARS. Totally insane.
And if you want to chase this mess be my guest. I AM WAITING.
And waiting...:1:

This has got to be the worst advice I have read on this site in the last half year at least. Dolby TrueHD vaporware?? Every Bluray player, and HD DVD for that matter supports TrueHD with an internal decoder. Any receiver released in the new year, and many at the end of last year support both Dts MA lossless and Dolby TrueHD.

All dolby digital chipsets(it hasn't been called AC-3 in years) are standardized. The same processing done in a multi thousand dollar pre-pro will be the same as what is in a low cost receiver. The only sonic difference has nothing to do with the chipset or the codec algorythm, but has to do with D/A conversion further down stream. No matter how you slice it, Dolby digital's lossy codec is audio of yesterday, and it is extremely poor advice to tell somebody to invest in a high end processor with yesterdays codec. There is no way in hell a lossy codec in a high end processor will sound better than DTHD lossless even in a cheap receiver. And considering the processor only supports bitrates up 640kbps, it wouldn't even be a close sonic match to DTHD.

Just to show you how bad this advice is, this fool doesn't even know that receivers that support DTHD and Dts MA lossless are already being sold, and have been since the middle of last year. If they include internal DTHD and Dts MA lossless it is likely they will not be obsolete within the next 5-10 years because they are 1.3 compliant already. Audio codecs do not change yearly, DD and Dts have been around at least 10 years on DVD. The reality is that you do not need a HDMI 1.3 compliant receiver to do any decoding. There is absolutely no advantage whatsoever of having anything more than a receiver that is either HDMI 1.1 compliant, or has 5.1 analog inputs. My old non HDMI receiver did just fine before I purchased my interim receiver to tide me over until I get a new pre-pro.

Advice is only as good as the person keeps up with the technology. Pix does not, and that is demonstrated over and over.

Sir Terrence the Terrible
02-25-2008, 02:10 PM
NOT REALLY.
If you notice most lines of receivers are the same basic device, with the same basic chassis, power and features are added as you go up the "line".
This saves cash
THE bLU BOYS haven't even finished finalizing their format, no one is going to come out with anything until things stabilize a bit.
No one wants to get stuck with an obsolete piece of gear.

Go to outlaw.com and check out their nice prepro, for example.
It has DVI switching.
Why? Because the nimrods running this industry have changed video connectors 3 or 4 times in about 4 years. How does a company base a business decision on such nonsense? ESPECIALLY A SMALL ONE?
They wait, thats what they do.
My receiver cost 1200 bucks, has wideband video switching and upconversion
and its just about obsolete, because it has component video switching

Not gonna get caught like that again, neither are the "big boys":1:

Ummm, not so bright, The bluboys standard has been long finished. The slow down is getting the chipsets out there, not the standards themselves. Keep up box head, you are falling way behind on the learning curve.

Sir Terrence the Terrible
02-25-2008, 02:14 PM
The lack of standards is deplorable and mind numbing when you consider what kind of crap the computer industry has been through. I understand that RCA coaxial digital out and Toslink lack the necessary bandwidth to pass through Dolby TrueHD. Why not beef up Those two standards using the same connector to make it backward compatible? I vote for Toslink 2 and RCA coax digital out version 2.0.

I really hate HDMI. weaving audio/video into the same connector/cable really limits my wiring options.If the a/v industry wants to get cute, they should take a lesson from the Playstation and use one port, but sell different cables that terminate into separate connectors. Apple in early 2000 tried to get cute with their ADC monitor cable which wrapped power, USB, and video in one cable using one connector. It was an elegant solution, but not practical at all. Today, with their monitors, they wrap all the cables in one bundle, but that bundle terminates into separate USB2, FireWire, video and power.

Will HDMI 1.3b and Blu-Ray profile 2.0 be the standard for the next ten years?

To answer you last question is yes. Profile 2.0 has always been the last profile. However Profile 2.0 is for those who like to download extra interactive features. If that is not your bag just buy any 1.1 profile player. Going forward I believe that the other profiles will be eliminated because the price of 2.0 components will drop to the point that its inclusion will not add a dime to the players price.

I also do not believe there will be a HDMI standard beyond 1.3b. There is no current equipment, or even any in the pipeline that would take advantage of 1.3b standards anyway.

pixelthis
02-26-2008, 01:22 AM
To answer you last question is yes. Profile 2.0 has always been the last profile. However Profile 2.0 is for those who like to download extra interactive features. If that is not your bag just buy any 1.1 profile player. Going forward I believe that the other profiles will be eliminated because the price of 2.0 components will drop to the point that its inclusion will not add a dime to the players price.

I also do not believe there will be a HDMI standard beyond 1.3b. There is no current equipment, or even any in the pipeline that would take advantage of 1.3b standards anyway.

FIRST you cuss me and then you prove my point.
Sure a non lossy codec will beat a lossy one like DD, thats not the POINT( not the one on your head)
The POINT is that people buying players sometimes have discs that dont play,
and the standards for thd , etc are not quite there yet, not to mention trying to find a disc with this new stuff.
THE STANDARDS havent quite settled down as of yet.
And the reason I suggested keeping an older receiver had NOTHING to do with advocating
DD over true hd or whatever, if you bothered to read (if you can read) my post I advocated letting the PLAYER do decoding duties, and use the six channel out.
Sure, buy a "new" receiver, pay a few grand, and watch it become obsolete like,
NEXT YEAR.
While you nimrods in the industry play with your "profiles" and "revisions " and "versions":1:

bobsticks
02-26-2008, 07:56 PM
Sir talky is as usual is wrong, all procs decoding ac3 are basically the same but how they do it is worlds apart.
My yamaha beat the pants off of a technics decoder I had.
As for "truehd" and other vaporware why worry about it?
THE MAIN THING TO WORRY ABOUT is the quality of the amps, and you wont
beat the proceed, dont worry about anything else in a receiver until the dust settles.


Question: Did you come to this conclusion using the same external amps, player, and speaker set-up? Were the two units even in the same room? We are, after all, talking about processors not receivers.

Rev2Liv
02-26-2008, 11:29 PM
To answer you last question is yes. Profile 2.0 has always been the last profile. However Profile 2.0 is for those who like to download extra interactive features. If that is not your bag just buy any 1.1 profile player. Going forward I believe that the other profiles will be eliminated because the price of 2.0 components will drop to the point that its inclusion will not add a dime to the players price.

I also do not believe there will be a HDMI standard beyond 1.3b. There is no current equipment, or even any in the pipeline that would take advantage of 1.3b standards anyway.

Thanks for the clarification on profile 2.0. 1.1 is all that I need/want.

My only concern is..... Sony usually introduces a reference quality model to appeal to enthusiasts when introducing a new standard. Sony's (DVP-S7000) was a 1st gen. model that still dishes out reference 480i 11 years later.

Will Blu-Ray picture quality continue to improve with better post processing chips or is the Sony BDP-S2000 Blu-Ray player as good as it gets? Or should I just shutup, grab a PS3 and hope Sony upgrades the post processing logic via software/firmware update?

pixelthis
02-27-2008, 12:00 AM
Question: Did you come to this conclusion using the same external amps, player, and speaker set-up? Were the two units even in the same room? We are, after all, talking about processors not receivers.

Very good question.
At the start technics had an exelent DD/DTS outboard decoder, cost about 300 bucks.
Had a deal with sears to get one and a Denon receiver that had no DD but did have a six channel in. Plugged the proc into that, and my DVD player into the proc.
The Technics and the Denon together were about 500 bucks, in a world of receivers that cost a grand, minimum that included DD, and not all had DTS.
The technics was quite nice, but sounded very uninspired on challenging material.
later I got a Yamaha rxv-750, had the propietary DD and sound chips that Yamaha made for themselves.
THE AMP WAS DIFFERENT, but the player, room, and speakers (B&W) were all the same.
And the difference was night and day.
LATER when I got my Integra the difference with its sound was also quite different, but it had prologicII and other enhancements, and was really a second generation type
machine, so its really not fair to compare it to the Yamaha.
Haven't kept up lately, haven't been in the market for a new receiver, maybe the newer ones are a bit more homogenized, or standardized.
But I have a friend with a HARMON AND HIS sounds a bit different than mine.
But its difficult to tell because of external factors.
I will tell you that engineers will put their own special twist on any product to try to differentiate it in a cookie cutter world:1:

pixelthis
02-27-2008, 12:02 AM
AND LET ME SAY THAT I would love to see a true lossless format out there, but
one that is standardized, and that will be around for awhile:1: