Denon AVR-S750H Decoding/Upmixing 2 Channel Stereo to Dolby Surround

[mdominic]

I'm going nuts. I bought a Denon AVR-S750H for 5.1 output from my LG CX 65". Sounds great. I didn't bother with the WebOS apps because I am an Apple TV 4K user. The Apple TV is plugged directly into my TV. I like using the Pure Auto setting. The Apple TV works perfectly with the Denon, switching between audio formats correctly. I decided to try out the WebOS on my LG. Whenever I played 2 channel stereo content from the WebOS it upmixes to Dolby surround unless I manually change it to a stereo mode on the Denon. I though this was an issue with the LG or the WebOS so I got a Firestick 4k and plugged that into the TV. Same issue. So after spending several hours on the phone LG "support" I decided that it could just be the Denon. So I took the Firestick and put it directly into the Denon and it had the same exact issue. So the Denon is not decoding the signal properly from any device other than the Apple TV. I even tried an older Apple TV and that worked as well. Why is this happening and how can I make it stop? I am usually able to figure thees things out, but I have met my match. PS: I can return the Denon if needed.

 

[lovinthehd]

Have no idea how the applish stuff works or not. However, I do have a firestick and a Denon avr.....and have no audio codec issues at all. If the app has the codec the Denon can handle it just fine and I use the firestick plugged directly into the avr as that's better audio possibilities than running it thru my tv (which I just use as a display).

My Denon can remember my general preference to use an upmixer on 2ch content (my preference mostly for tv/movie apps), so until I change it 2.0 content will come out as Dolby PLIIx as I prefer. However, if I then set my preference that 2ch content is treated as stereo, it will play it in stereo until I change my preference for that input/codec.

So no matter the app, if it's 2ch content in the app your Denon still uses Dolby Surround upmixer, even after you go into sound mode selection and choose stereo?

 

[mdominic]

Have no idea how the applish stuff works or not. However, I do have a firestick and a Denon avr.....and have no audio codec issues at all. If the app has the codec the Denon can handle it just fine and I use the firestick plugged directly into the avr as that's better audio possibilities than running it thru my tv (which I just use as a display).

My Denon can remember my general preference to use an upmixer on 2ch content (my preference mostly for tv/movie apps), so until I change it 2.0 content will come out as Dolby PLIIx as I prefer. However, if I then set my preference that 2ch content is treated as stereo, it will play it in stereo until I change my preference for that input/codec.

So no matter the app, if it's 2ch content in the app your Denon still uses Dolby Surround upmixer, even after you go into sound mode selection and choose stereo?

Sorry. i didn't get a notification that you replied.

Yes, 2ch content is upmixed from everything other than the Apple TV. The Apple TV works fine I must be doing something wrong. I use Pure Auto so I can't imagine what I could do differently. How do you set your preference that 2ch content is treated as stereo?

 

[lovinthehd]

Sorry. i didn't get a notification that you replied.

Yes, 2ch content is upmixed from everything other than the Apple TV. The Apple TV works fine I must be doing something wrong. I use Pure Auto so I can't imagine what I could do differently. How do you set your preference that 2ch content is treated as stereo?

Does the atv output as multich pcm or as bitstream? What are the audio output choices in the atv? I don't know what pure auto is, not a choice on either of my Denons, but if it's like direct/pure direct settings on mine that would prevent use of an upmixer. If I use a given input for 2.0 content as "stereo" it stays that way until I choose something else, like PLIIx.

 

[mdominic]

My Apple TV is outputting as LPCM. That's the only difference that I can see. I have my TV set to AUTO (same result as pass through). If I set the TV to PCM I only get 2 channel audio out to the receiver. Pure Auto is ads no color to the sound though I can use the Audyssey Dynamic EQ and MultiEQ with it. If I use MOVIE and set it to STEREO is works but then when I play something with surround it stays in stereo.

 

[lovinthehd]

Same on my avrs generally in that case, I lose the ability to use the Dolby or DTS upmixers on lpcm content when that's all my stream app/device offered.....what are all the audio setting choices on your atv? (I'd guess because it assumes you're already in a multich mode with lpcm it doesn't allow the other upmixers to function?). So the auto pure is a setting on the atv or the denon? What is "movie" setting particularly or is that how an input is labeled?

 

[mdominic]

There aren't many choices on the ATV. I'll include a photo.

The PURE AUTO is on the Denon. There is also PURE DIRECT, but that doesn't allow the use of DynalmicEQ. The MOVIE settings are formats that can be chosen. I'll add screenshots from the manual as well.

 

[lovinthehd]

There aren't many choices on the ATV. I'll include a photo.

The PURE AUTO is on the Denon. There is also PURE DIRECT, but that doesn't allow the use of DynalmicEQ. The MOVIE settings are formats that can be chosen. I'll add screenshots from the manual as well.

Yes, sound mode names/options aren't consistent even within a brand. Interesting it allows DynamicEQ in "pure auto" which leads me to think it enables Audyssey as my Denons cannot implement DynamicEQ without Audyssey engaged (altho my Onkyo can, so maybe its just a choice Denon made, hard to know). Okay, so the "movie" button that yields sound mode options on your remote, that my Denons also have (and on mine have to depress for several seconds to see the options). All I see on the ATV is the Dolby Atmos/LPCM mode.....any other choices?

 

[mdominic]

Yes, sound mode names/options aren't consistent even within a brand. Interesting it allows DynamicEQ in "pure auto" which leads me to think it enables Audyssey as my Denons cannot implement DynamicEQ without Audyssey engaged (altho my Onkyo can, so maybe its just a choice Denon made, hard to know). Okay, so the "movie" button that yields sound mode options on your remote, that my Denons also have (and on mine have to depress for several seconds to see the options). All I see on the ATV is the Dolby Atmos/LPCM mode.....any other choices?

No other choices on the ATV.

 

[lovinthehd]

No other choices on the ATV.

So it's just no option for audio on the ATV? That seems odd from the little I read when looking up such....but perhaps model/version makes a difference? What do you have?

 

[mdominic]

So it's just no option for audio on the ATV? That seems odd from the little I read when looking up such....but perhaps model/version makes a difference? What do you have?

For the ATV? If I turn off the Change Format I believe I could choose. I can also change between 16bit and Auto. I have the 4k version.

 

[lovinthehd]

For the ATV? If I turn off the Change Format I believe I could choose. I can also change between 16bit and Auto. I have the 4k version.

Try 16bit version.

 

[mdominic]

T

Try 16bit version.

The ATV is the thing that works perfectly. It's anything else that upmixes.

 

[lovinthehd]

T


The ATV is the thing that works perfectly. It's anything else that upmixes.

Not sure what that means. The avr can only deal with what audio stream the atv feeds it, does the 16bit give your avr the option for sound mode or not?

 

[Trebdp83]

It’s all a mess with Dolby from devices to AVRs. Different AVRs can do different things with a Dolby signal. Some like my Yamaha let you apply DTS processing to a Dolby signal while my Onkyo does not. Apple TV 4K does not bitstream Dolby Digital+ so an Atmos track will display as Atmos/PCM rather than Atmos/Dolby Digital+ as on other devices. You can set the ATV4K to ignore the Atmos metadata and it will just display PCM. You can change the format and this will result in the audio signal being sent as Dolby Digital 5.1, no PCM, no Atmos. Leave it on Auto, Atmos Available and make sure Dolby Atmos is set to On. Check the Denon manual for DSP modes applicable to Dolby signals. Most should be available with a non Atmos PCM track but will have more limitations with an Atmos track. The Apple TV 4K can send 48khz/24bit Atmos signals and the Denon can handle it so leave it on Auto and don’t limit it to 16 bit. Dolby would have confused less folks with PLIII instead of Dolby Surround but it is what it is. Set it how you like it and enjoy.

 

[Trebdp83]

Now, keep in mind all bets are off when you connect your devices directly into the TV even if it is supposed to pass everything along to the receiver without messing it up. ARC/eARC should be used for the TVs tuner and apps and external devices really should be connected directly to the AVR to avoid audio input issues. Hope you work it out.

 

[mdominic]

Not sure what that means. The avr can only deal with what audio stream the atv feeds it, does the 16bit give your avr the option for sound mode or not?

The Apple TV is not the problem. It's everything else like the TV or firestick. They upmix everything that are two channels.

 

[Trebdp83]

You need to look at the input signal going into the Denon and also the output. Putting the Denon into Direct mode will show you what each device is sending to it as only those channels will be output to the corresponding speakers. A two channel signal will play only through the front speakers in direct mode. There is no standard for the same audio to be sent from the same streaming app from different devices. When the Denon is in Dolby Surround mode, it will send two channel audio into all of the channels the way Pro Logic did in the past. Remember, the Apple TV 4K is sending PCM for everything in Auto mode except Atmos. So, no Dolby flag is hitting the Denon. The other devices are bitstreaming a Dolby signal and the Denon may be automatically going to Dolby Surround mode. That doesn’t necessarily mean they are upmixing anything.

 

[lovinthehd]

The Apple TV is not the problem. It's everything else like the TV or firestick. They upmix everything that are two channels.

Okay, sorry, got lost back there a bit with the atv in the mix, had to reread. I like Treb's post. What are the audio settings possible in the Firestick 4K? Mine is regular Firestick so curious what the difference is (I use the DD+ Automatic setting). I get no forced upmixing, doubt the Firestick is capable.

 

[mdominic]

You need to look at the input signal going into the Denon and also the output. Putting the Denon into Direct mode will show you what each device is sending to it as only those channels will be output to the corresponding speakers. A two channel signal will play only through the front speakers in direct mode. There is no standard for the same audio to be sent from the same streaming app from different devices. When the Denon is in Dolby Surround mode, it will send two channel audio into all of the channels the way Pro Logic did in the past. Remember, the Apple TV 4K is sending PCM for everything in Auto mode except Atmos. So, no Dolby flag is hitting the Denon. The other devices are bitstreaming a Dolby signal and the Denon may be automatically going to Dolby Surround mode. That doesn’t necessarily mean they are upmixing anything.

Theses are my results. I played a 2 channel stereo file from the SmartTV and as always it played as DDSur upmixing to all speakers. I pressed the status button on the front while in ARC and then eARC

For ARC it read:

Sig: DD
fs :48Hz
Format: 2/0/.0
Input=ARC

For eARC it read:

Sig: PMC
fs :48Hz
Format: 2/0/.0
Input=eARC

Shouldn't that NOT upmix when in Pure Auto and just play in 2 channel stereo? I am very confused. I tried a Yamaha TSR-700 (RX-V6A) receiver yesterday and that works fine, but it doesn't sound as good to me so I really want to figure this out.

Like I mentioned the Apple TV works fine with the Denon. The Apple TV is outputting as LPCM. That's the only difference that I can see. AND I do mostly just use the Apple for watching, but I don't know what the future holds.