Blu-ray downmix to 5.1 DTS via optical/coax SPDIF?

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grolschie

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#48894 17-Nov-2009 14:29

Hi there,

Do all Blu-Ray players downmix to 5.1 full bitrate DTS via the SPDIF ouputs? Or do only specific models do this? I don't have an HDMI receiver, but it does decode DTS 6.1.

Thanks in advance.
grol

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1439 posts

Uber Geek

#274293 18-Nov-2009 18:51

Most BDPs will downmix DD/DTS.

What model BDP/AVR do you have ?

If you don't have HDMI do you have 5.1 analogue out on your BDP and a 5.1 input on your AVR ?

HD sound is essential for the full HD experience.

grolschie

911 posts

Ultimate Geek

#274294 18-Nov-2009 18:54

Hello. I haven't got a blu-ray player as yet. I have an Onkyo receiver with analog inputs, optical and coax SPDIF, but no HDMI.

bazzer

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#274301 18-Nov-2009 19:19

Analog is your only way to get high def sound.

grolschie

911 posts

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#274336 18-Nov-2009 22:04

Thanks. If a receiver only has 5.1 analogue inputs and the blu-ray player has 7.1 output, what happens with the signal from the other 2 channels?

lchiu7

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#274344 18-Nov-2009 22:37

grolschie: Hi there,

Do all Blu-Ray players downmix to 5.1 full bitrate DTS via the SPDIF ouputs? Or do only specific models do this? I don't have an HDMI receiver, but it does decode DTS 6.1.

Thanks in advance.
grol

Depends on the audio in the BluRay disc. Disc usually have DD 5.1 (rarer now) or HD audio viz. Dolby TrueHD or DTS HD Master.

Dolby TrueHD has a companion DD5.1 track, usually at 640Kbs which would be sent out via SPDIF. DTS HD Master consists of a DTS core and additional audio information to make it lossless. Over SPDIF only the core would be sent. Note that either of these cut down audio tracks are still very good but if you are a purist, you will want lossless audio which can only be achieved via HDMI and a receiver that can either decode the bitstreamed data or your BluRay player decodes it and outputs it as PCM.

As an aside on those rare discs that have 7.1 audio, if you only have 5.1 in your AVR, you can usually tell the player to downmix the rear channels.

Staying in Wellington. Check out my AirBnB in the Wellington CBD. https://www.airbnb.co.nz/h/wellycbd PM me and mention GZ to get a 15% discount and no AirBnB charges.

grolschie

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#274345 18-Nov-2009 22:41

Thanks for that. :-)

bazzer

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#274362 18-Nov-2009 23:28

lchiu7:
grolschie: Hi there,

Do all Blu-Ray players downmix to 5.1 full bitrate DTS via the SPDIF ouputs? Or do only specific models do this? I don't have an HDMI receiver, but it does decode DTS 6.1.

Thanks in advance.
grol

Depends on the audio in the BluRay disc. Disc usually have DD 5.1 (rarer now) or HD audio viz. Dolby TrueHD or DTS HD Master.

Dolby TrueHD has a companion DD5.1 track, usually at 640Kbs which would be sent out via SPDIF. DTS HD Master consists of a DTS core and additional audio information to make it lossless. Over SPDIF only the core would be sent. Note that either of these cut down audio tracks are still very good but if you are a purist, you will want lossless audio which can only be achieved via HDMI and a receiver that can either decode the bitstreamed data or your BluRay player decodes it and outputs it as PCM.

As an aside on those rare discs that have 7.1 audio, if you only have 5.1 in your AVR, you can usually tell the player to downmix the rear channels.

Or having the player output via analog, no?

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bazzer

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#274363 18-Nov-2009 23:28

Jaxson

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#274421 19-Nov-2009 10:02

Re HD audio, there's kinda 3 options:
One is the player can't decode the HD audio, so it just passes the info on via hdmi (bitstreaming) to a receiver that can then decode the HD audio.
Two is the player can decode the HD audio and it send on the raw decoded info (L/PCM) onto the receiver via hdmi. In this case receiver doesn't need to know how to decode the HD audio itself.
Three is the player can decode the HD audio and output the raw analogue sound as a whole heap of rca plugs at the back. You then need a receiver that can accept this type of input, ie has a similar set of rca inputs at the back.

Points to note are:
Not all players with rca outputs output full HD audio via them. I remember one of the samsungs was like this, only ever gave you the base DD or DTS signal via the rca's.
When using the rca inputs, none of your receiver setups like speaker size/distance/sound modes etc work. All this has to be recreated in the player itself.
Sometimes the above happens too when using LPCM inputs into hdmi, this depends on the receiver though.
You have to spend a lot more to get a bluray player that can internally decode all the HD audio formats, and that has analogue outputs. When I went through this exercise, I found it smarter to just sell the receiver on trademe, and buy a new receiver, with a cheaper bluray player.

lchiu7

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#274433 19-Nov-2009 10:58

..
You have to spend a lot more to get a bluray player that can internally decode all the HD audio formats, and that has analogue outputs. When I went through this exercise, I found it smarter to just sell the receiver on trademe, and buy a new receiver, with a cheaper bluray player.

And with HDMI the cabling is so much cleaner - one cable handles all the HD audio and video.

Staying in Wellington. Check out my AirBnB in the Wellington CBD. https://www.airbnb.co.nz/h/wellycbd PM me and mention GZ to get a 15% discount and no AirBnB charges.

ilovemusic

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#274528 19-Nov-2009 16:37

The convenience of a single cable run (HDMI) can't be understated.

But if you are attached to your existing AVR, get a BDP that hass on-board decoing and analogue outputs.
Eg. Sony BDP-S760, Panasonic DMP-BD80 etc.

The Panasonic is particularly good value, often discounted to well below the $850 rrp and a superb performer.

Don't worry about bass management etc.
Yu will get far better results by physically moving the speakers than by electronic manipulation.

Jaxson

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#274651 20-Nov-2009 08:58

ilovemusic:
Eg. Sony BDP-S760, Panasonic DMP-BD80 etc.

The Panasonic is particularly good value, often discounted to well below the $850 rrp and a superb performer.

This was the bit that sounded counter intuitive to me. You're having to buy the more expensive bluray players to connect to an old fashioned receiver. If you spend a little bit more, you can buy a modern hdmi capable receiver which allows you to purchase a cheaper bluray player. This is a better option if you can afford to spend a bit more and/or sell your existing receiver on trademe.

lchiu7

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#274656 20-Nov-2009 09:20

Good point. For $800 you can get a PS3 and have a much more capable media device. For my money I would go for a competent BD player that output over HDMI and look at a good AVR that can handle HD audio over HDMI.

Staying in Wellington. Check out my AirBnB in the Wellington CBD. https://www.airbnb.co.nz/h/wellycbd PM me and mention GZ to get a 15% discount and no AirBnB charges.

ilovemusic

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#274792 20-Nov-2009 18:07

Jaxson:
ilovemusic:
Eg. Sony BDP-S760, Panasonic DMP-BD80 etc.

The Panasonic is particularly good value, often discounted to well below the $850 rrp and a superb performer.

This was the bit that sounded counter intuitive to me. You're having to buy the more expensive bluray players to connect to an old fashioned receiver. If you spend a little bit more, you can buy a modern hdmi capable receiver which allows you to purchase a cheaper bluray player. This is a better option if you can afford to spend a bit more and/or sell your existing receiver on trademe.

Not at all counterintuitive.

There are many great sounding older AVRs that lack HDMI connectivity but have a 5.1/7.1 analogue input.

For these a BDP with onboard decoding is ideal.

Plus many of the cheap HDMI equipped AVRs sound pretty crappy, even when fed an HD audio signal.

richms

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#274857 20-Nov-2009 23:31

Bass management is essential IMO - less now that the movies are getting their mastering right and realizing that the .1 on the disc is OPTIONAL to have in the spec. Still a load of music DVDs out there that highpass all channels and lump all the bass in the .1 channel so you have to mix that to the mains rather than the sub so that you get the music closer to how it is supposed to be.

Still not seen a consumer amp that does anything other than volume on the 5.1 analog in, and the management on the players is about non existant.

Really there should be nothing in the .1 track on music since it is not an effect, it is part of the content, but most discs seem to duplicate the mains below 80-120Hz or so, so if you low pass it into your sub you get more bass, often too much more if you have proper speakers that go low enough for your mains.

Richard rich.ms

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