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Discussion Starter #1 (Edited)
As more and more surround modes become available on new receivers the confusion over what mode I should use for a particular surround format on DVDs and BluRay movies.

Below is a bit of info as to what works best with what format.

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Since the early 1990's Dolby surround formats have been available for home use to the general public. I wont get into the technical details as it is not necessary but if you wish you can find lots of information here.
Basically if you have a receiver that is less than 10 years old it will have several Dolby formats available to you.




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Within the last few years several new formats have popped up including Dolby Digital EX, Dolby Tru HD, DTS ES and DTS Master audio More info on DTS formats here.
In the early years of surround Dolby Pro logic was the only format available to us at home and was a non digital format meaning that all the information was simply embedded into the two analog stereo channels and then sent to a centre channel and two rear speakers that were mono. Several receiver companies Yamaha being one of the first also added several theatre modes and other room and Stadium surround modes that in there day were fantastic.

With the consumer market expanding and demand for better home theater rooms, companies needed to come up with the same formats that were originally only available to those theaters.

DVDs have over the past 8 years or so made available digital surround formats allowing up to 6 channels and one subwoofer mix to be used. Now with BluRay and HD DVD's offering us newer uncompressed formats the envelope has expanded to the point that you can get even better sound than any commercial theater right in your own home, offering up to 7 channels and one subwoofer mix in fully uncompressed audio meaning that the sound is as close to the original recording as possible.

This is where the confusion begins for many newcomers to home theater.
First lets look at what choices you have,
On a standard DVD you usually only had a few choices and only two of them would be a digital format. Dolby digital 5.1 is the most common by far and is just what it says, 5 channels and 1 sub channel. You may also see the option to use ocationally Dolby digital EX/DTS ES basically the same mix but with an added 6th rear channel but most people only had a receiver capable of decoding just the 5 channels and sub.
Today this is not the case, alot of receivers have full 7 speaker outputs along with a sub or even two. So the question is if your using a receiver with all 7 speakers hooked up what format is best in order to hear sound out of all 7 speakers.

First lets get one thing clear. If you have a receiver that supports the newest audio formats (DTS MA & Dolby TruHD) and your using a BluRay player. The only two ways that you can use these formats is if you are connected to the receiver with a HDMI cable or your BluRay player has multi channel analog outputs on the back and you run them into the inputs on the receiver.

On all movies there will be a audio menu, in this menu you will have choices as to what surround format you want to use. If your receiver only has 5.1 channels do not select the modes that have more such as 6.1 or 7.1. If you have a 7.1 channel receiver and you only have 5.1 hooked up this is not necessary as the receiver will automatically take the extra channel(s) and put them into the 4th and 5th channels if you have it set up properly.
Another question I get alot is if "I have a 7.1 speaker setup and the audio format on the movie is only 5.1 what do I use?" If you simply use the default mode on your receiver corresponding to the one selected on the movie you will not hear anything out of the rear speakers. You will need to find a mode that can extrapolate the information from the 5.1 mix and it will send it also to the 6th and 7th channels.
On my receiver I have several THX modes that will do this automatically but you must have a THX certified receiver to have access to these modes. Your manual will explain the modes available to you so have a look there.

I hope this information helps, If you have any questions or comments feel free to do them in this post.
 

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Great post, thanks for all the info.

Based on this I'm not able to get Dolby True HD, I don't think my Onkyo 503 receiver supports True HD or DTS Master Audio, it would have to, right? Also I'm using an optical cable from the blue ray into my receiver not HDMI. I am using HDMI for video directly into my 1080 tv. I heard using HDMI for both audio and video into my receiver will degrade the video. It's not a very high end receiver.

Why does Dolbly true HD/DTS-MA require HDMI for audio? Why can't optical support it?
 

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Discussion Starter #3
Great post, thanks for all the info.

Based on this I'm not able to get Dolby True HD, I don't think my Onkyo 503 receiver supports True HD or DTS Master Audio, it would have to, right?
Yes it would but you have other options to make it work.
does your receiver have multi channel analog inputs? if so you can output the DTS MA and TruHD using the Bluray players analog outputs to the receiver that way. The bluray player has the ability to decode the uncompressed formats its self you just have to tell it to in the players menu.
Also I'm using an optical cable from the blue ray into my receiver not HDMI. I am using HDMI for video directly into my 1080 tv. I heard using HDMI for both audio and video into my receiver will degrade the video. It's not a very high end receiver.
Video through the receiver being degraded is a possibility but not always, the way you have it now will work just fine.

Why does Dolbly true HD/DTS-MA require HDMI for audio? Why can't optical support it?
This was a decision made buy the powers that be, It is a sort of copywrite protection.
 

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I thought the reason Optical couldn't handle HD audio signals was due to bandwidth issues. That due to the light having to travel usually over 3 feet that its bandwidth was having issues carrying the HD signal or something. I can't remember exactly, but something close to that effect.
 

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Optical is more than capable of handling the uncompressed formats. Dolby Digital plus as well as DTS both have high bitrates and work fine over optical.
Fiber optics is used in many commercial networking systems and has alot more bandwidth than you may think.
 

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I thought so too, but i went researching that kind of stuff, but didnt find many sites that helped. Only one or 2 that went into depth about bandwidth or stuff with fiber optics. So, I guess that site wasnt of much help, or maybe on a different topic.
 

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I did find that 6 channel audio is the maximum allowed over optical but again this is just a rule not that it is not capable of doing more.
Another interesting tidbit is that DTS MA uncompressed audio carries by default a lossy core which can be read by regular DTS decoders but dont read this wrong it is not uncompressed in this format just a high quality lossy track.
 

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What does Lossy mean?
 

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it seems that my components will not support Dolbly true HD or DTS-MA. So now for the $69,000 question. Would I notice the difference???
 

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it seems that my components will not support Dolbly true HD or DTS-MA. So now for the $69,000 question. Would I notice the difference???
If you have a good speaker system then yes you would hear a difference but if your using small bookshelves and a small sub then most likely not.
 

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Even if you had a 1000$ per speaker set up, you might not see a difference even. Not everyone has the ears for it.

But it goes back to a discussion the forum had a long time ago, which is does the concept of all this just make you think it sounds better? Like using the Monster speaker cable and all that stuff for every connection, spending that 100$ for it compared to 11$ sure in makes you hope it was worth it. as well as even think you see more colors or better contrast ratio
 

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Even if you had a 1000$ per speaker set up, you might not see a difference even. Not everyone has the ears for it.
True but remember if you can tell the difference between a good quality mp3 file and the real CD recording then the same will be true for the difference between regular Dolby digital and the uncompressed formats.
 

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Hmm, I was wanting to continue our talk bout this.

On wikipedia I was researching Dolby HD, and DTS HD, and saw this for the Dolby HD part.

S/PDIF cannot carry Dolby TrueHD due to bandwidth limitations, as S/PDIF is limited to 5.1 channels of compressed discrete audio. When using S/PDIF, a device such as a Blu-ray Disc player will automatically send the Dolby Digital audio.
 

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Yes, That is correct Dolby TruHD and DTS MA can only be sent over HDMI. But this is not only due to bandwidth limitations it is also a copy protection rule.
 

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Well than Tony, we should correct this error on Wikipedia than.
 

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I still have questions about listening modes. My set-up: Onkyo TX-SR805 with 7.1 speakers, HDMI connections, so I get all of the sound choices. But there are so many sound choices with this unit, I get confused over which is best other than through experimentation (which sometimes gets difficult, switching between modes while trying trying to hear differences in various speakers around the room.) For example, if a movie has a DTS track would be it be best to just play it in DTS? Sometimes, I think the Ultra Cinema 2 sounds better. Also, what about THX modes? What do these offer that others do not. Are there guidelines to follow? Thanks.
 

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Keep in mind that the THX modes like Ultra Cinema 2 (the one I use alot) is placed on top of the DTS track for example so your not degrading DTS only enhancing it so it spreads the audio properly over the back two channels.
The same goes for the uncompressed audio if you look closely at the display on your receiver when these modes are being received you will see the DTS MA logo lit even when you have the THX Ultra Cinema 2 on the main display.
 

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You are correct about the DTS logo being lit on the display even though THX Ultra Cinema 2 on the main display. That was one of the reasons why I am getting so confused. Does the same hold true for other modes such as Dolby digital EX/DTS ES, etc.? If so, appears that Ultra Cinema 2 is the overall best choice (I like the sound it reproduces very much.) Thanks for the reply.
 
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