# Dolby surround decoding issues?



## pgoelz (May 1, 2005)

Those of you that watch Colbert on CBS....... is there supposed to be any audience ambiance during non-musical segments? On my setup at least, there is ambiance from the rear speakers during portions where the band plays but none at all during segments with Colbert at the desk. 

Then last night, during segments of The Late Show where normally I don't hear rear speaker ambiance, there was some vestigial output that came and went and became distorted at about a 1Hz rate. I cycled through all the various Dolby settings on the receiver and nothing seemed to cure it. Until suddenly I realized it was working normally again. I'm back to "Dolby Pro Logic II Movie" and it seems to be working normally (including the same Late Show recording from last night). I'm puzzled. 

The Bolt is connected to the Samsung 46" TV via HDMI and set to Dolby Digital audio output (same results set for PCM only). The Samsung is connected to a Sherwood RD-6500 receiver via optical. 

I note that the 1Hz rate to the distortion etc. would seem to be related to a 1Hz "popping" that occurs during pause and began after a firmware update a year or two ago. I reported it here at the time and no one else was reporting it so maybe there is something odd between the Bolt and the TV and/or the receiver? If I connect the Bolt directly to the receiver via optical there is no popping but I can't leave it that way because there isn't an easy way to turn the TV AND the receiver off simultaneously with the Tivo remote. 

Has anyone else had odd Dolby decoding issues? Is this unique to my setup perhaps? 

Paul


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## JoeKustra (Dec 7, 2012)

I always record The Late Show. I can't recall any audio issues. Last night, which I haven't watched yet, was missing SkipMode. I'll post after I watch it.

My Roamio feeds a Yamaha RX-V867 in a 5.1 configuration and then on to a Sony TV. Almost all my HD channels are in DD 5.1.


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## pgoelz (May 1, 2005)

JoeKustra said:


> I always record The Late Show. I can't recall any audio issues. Last night, which I haven't watched yet, was missing SkipMode. I'll post after I watch it.
> 
> My Roamio feeds a Yamaha RX-V867 in a 5.1 configuration and then on to a Sony TV. Almost all my HD channels are in DD 5.1.


Do you hear audience ambiance through the rear speakers when it is just Colbert at the desk? I have always thought it was odd that ambiance is only present during musical segments.

If you have the Tivo connected to your receiver and the receiver feeds the TV, how do you turn things on and off? Do you have to turn the receiver and the TV on and off separately?

Paul


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## JoeKustra (Dec 7, 2012)

pgoelz said:


> Do you hear audience ambiance through the rear speakers when it is just Colbert at the desk? I have always thought it was odd that ambiance is only present during musical segments.
> If you have the Tivo connected to your receiver and the receiver feeds the TV, how do you turn things on and off? Do you have to turn the receiver and the TV on and off separately?
> Paul


I never noticed anything special about the audio as compared to The Tonight Show or Jimmy Kimmel Live which I also record when new episodes.

My TiVo remote controls the TV power. One button on the AVR remote gets power and selects the input. I have seven remotes close to me. I've never been afraid of remotes. When I will be away from my viewing space for over an hour, I usually just mute the AVR and power off the TV. The AVR controls three TiVo units, Blu-ray and Roku Ultra. I may be a poor test since I use DSP when viewing TV, but the sub is enabled with an LFE signal only. Networks like SyFy and Comet (SD) are DD 2.0 only.


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## pgoelz (May 1, 2005)

I have done a lot more hacking around this morning and I am just as confused as when I started. Dolby is working perfectly.... no idea what the issue was last night. But I have a guess.... I started noticing issues last night after watching a program on the Smithsonian channel that had severe pixellation and audio mutes during the last half hour of the show. I wonder if the (assumed) corrupted data stream confused my Sherwood RD6500 receiver. And perhaps all my menu and parameter switching and disconnecting the optical cable caused it to finally reset? 

I also note that if the Bolt feeds the TV (via HDMI) and the TV feeds the receiver (via optical) that the receiver stays in Pro Logic mode regardless of program content. So the TV is doing something to the digital data stream and perhaps is not 100% compatible with the receiver? 

It is very frustrating trying to dig into this stuff, only to find that there is insufficient documentation available to figure it out. For example, Samsung makes no mention whatsoever of how the optical audio output differs from the HDMI audio input. There is SOME difference because it causes subtle changes to how the Sherwood RD6500 reacts to it. 

I'm thinking this boils down to the way Dollby encodes and decodes the various channels and what (if any) level and phase manipulation happens to the signal passing through the TV. But short of trying a different receiver, I'm not sure what to do about it when the audio gets funky next time. 

Paul


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## JoeKustra (Dec 7, 2012)

Not all televisions will send anything higher than DD 2.0 out their optical port. If you have access to Comedy Central it is usually DD 2.0 and there is an obvious difference in the "presence" even with DSP applied by my Yamaha. I have no source of Pro Logic.


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## HerronScott (Jan 1, 2002)

pgoelz said:


> If I connect the Bolt directly to the receiver via optical there is no popping but I can't leave it that way because there isn't an easy way to turn the TV AND the receiver off simultaneously with the Tivo remote.


If you buy the TiVo Slide Pro Remote, it can control power for up to 3 devices with the power button.

https://support.tivo.com/articles/F...the-Learning-Feature-of-TiVo-Learning-Remotes

Scott


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## kpeters59 (Jun 19, 2007)

pgoelz said:


> If you have the Tivo connected to your receiver and the receiver feeds the TV, how do you turn things on and off? Do you have to turn the receiver and the TV on and off separately?


If you complete both the 'TV' portion of Remote Setup and the 'AV' portion of Remote Setup, your TiVo remote _should_ be able to operate both TV and AV power when you press the TV Power Button.

Also, A fiber optic cable from your TV to the Stereo is never going to be as good of audio as HDMI directly in to the Receiver.

-KP


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## HerronScott (Jan 1, 2002)

kpeters59 said:


> Also, A fiber optic cable from your TV to the Stereo is never going to be as good of audio as HDMI directly in to the Receiver.


Is that true for the sources available through a TiVo especially with a 5.1 setup? I searched and only found mention that optical doesn't support Dolby TrueHD and DTS HD Master Audio. Does any TiVo source support 7.1 audio?

Scott


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## Luke M (Nov 5, 2002)

Assuming your TV can accept and pass through Dolby Digital (that's been a standard feature for years), there's no decoding involved. If the TV can only accept PCM, then the Tivo will decode and downmix the Dolby Digital to 2-channel PCM (regardless of the setting).

That reminds me, Tivo's decoding does have a flaw (at least on the S3, I haven't checked newer models), which is that the output is always Dolby surround encoded. There's no stereo option! Surround encoding messes with the phase of the surround channels, which sounds weird in stereo.


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## pgoelz (May 1, 2005)

kpeters59 said:


> If you complete both the 'TV' portion of Remote Setup and the 'AV' portion of Remote Setup, your TiVo remote _should_ be able to operate both TV and AV power when you press the TV Power Button.
> 
> Also, A fiber optic cable from your TV to the Stereo is never going to be as good of audio as HDMI directly in to the Receiver.
> 
> -KP


Just a follow up here. I successfully programmed the power button on both our slide remotes this morning. Turns out that if the remote is already programmed to operate the TV, when you do the learn mode programming for the power button it does not erase any other programming. The end result is now the power button operates the receiver and the TV and all the other buttons like mute Channel and volume still work without any further programming. Thanks for the tip.

Paul


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## pgoelz (May 1, 2005)

And a further followup.... I broke down and replaced my old Sherwood AVR (no HDMI inputs) with a Yamaha RX-V385. HDMI from bolt, DVD and PC to the AVR, then HDMI from AVR to the TV. Zero Dolby decode issues, no periodic popping in standby, perfect lip sync and overall subtly better sound..... more "present" and cleaner sounding than the optical audio cable setup I was using with the Sherwood. 

Getting it working reliably was a bit of a struggle. VERY poor documentation made it difficult to figure out why various things were not working correctly. 

Still have to use the Tivo Slide learning feature to power the TV and AVR at the same time. The AVR can be configured to turn off when the TV turns off, but once off it will not turn back on when the TV turns on so you still need to program the Tivo remote to send I/R power toggles to both the AVR and the TV. 

Another serious issue I discovered when shopping was that all AVR remotes I saw EXCEPT the Yamaha do not toggle from input to input.... they have a discrete button to select each receiver input. Problem with that is that there is only one INPUT button on the Tivo remote so you can't program the Tivo remote to change inputs. Fortunately, the Yamaha remote has an input UP and DOWN button so I programmed the Tivo Slide to operate the Yamaha input UP function and I can cycle through the inputs on the Slide remote. 

So.... $229 poorer but a happy camper. 

Paul


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