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Question Straight versus Surround Decoder

LASound

Novice Member
I have a Yamaha RX-A760 receiver. I'm using DirecTV NOW, but when I have the receiver set to Straight, I only get sound from the Front (L+R). When I set it to Surround Decoder, I get total 5.1 surround, which is how I have my system set up.

When I watch Netflix in Straight Mode, I get surround. My questions are:

1) Is the Surround Decoder true 5.1 or a simulation?

2) When I have it set to Surround Decoder and watching a 5.1 movie, am I getting true 5.1 or a simulation?

Thanks in advance!
 

Rambles

Distinguished Member
Hi, it depends on whether the source audio is stereo or 5.1.

The surround decoder will upmix stereo content to create audio for all 5.1 speakers. If you select straight on stereo content, then audio will just come from the front left and right speakers.

If you are selecting straight and getting audio from 5.1 speakers then the source content has a 5.1 soundtrack.
 

LASound

Novice Member
Well the source is stereo at the moment, while other's using DirecTV NOW with Fire TV have 5.1. I guess they haven't implemented that into the Apple TV yet. But when I do have it in Surround Decoder Mode, everything sounds identical to when I have it in Straight Mode, or so it seams.
 

dante01

Distinguished Member
STRAIGHT would give you the audio as it is without any additional upmixing applied. If the source content was 2 channel stereo then only your front left and right speakers will have been employed if the receiver were set to the STAIGHT mode. You'd only get audio via the other speakers using STRAIGHT if the audio coming into the receiver has discrete channels of audio for them.

The SURROUND DECODER modes include options than can upmix audio that lacks dicrete channels to utilise all of your speakers even if the source audio lacks discrete channels for them.

If you set the receiver to a SURROUND DECODER mode such as DOLBY SURROUND or NEURAL:X then they'd be effectively overriden and not used in conjunction with multichannel audio formats that include at least 5.1 discrete channels of audio.
 

LASound

Novice Member
I think I understand.

Just to be clear, Straight 5.1 and Surround Decoder 5.1 isn't the same, correct? In other words, if I play a Blu-Ray movie at 5.1, is the 5.1 surround coming out of my speakers identical whether I set it to Straight or Surround Decoder? Thanks again!
 

Rambles

Distinguished Member
With the Yamaha AVR's you do have the option to apply processing to 5.1 soundtracks, so you can alter the sound to add effects.

So, if you want to hear the original 5.1 soundtrack use straight mode.
 

dante01

Distinguished Member
Discrete 5.1 would result in you getting 5.1 audio if using the STRAIGHT mode. THe STRAIGHT simply bypasses any SURROUND DECODER upmixing modes or DSP PROGRAMS that may have overwise been engaged prior to engaging the STRAIGHT mode.

The SURROUND DECODER modes effectively create pseudo channels of audio for the speakers you have within your setup that the discrete incoming audio lacks channels for. If the source is stereo in nature then a SURRUND DECODER mode such as DOLBY SURROUND will create pseudio channels for your centrem surrounds and sub. If the incoming audio wre 5.1 or 7.1 in nature then the mode wouldn't be required and wouldn't be applied because the incoming audio already includes discrete channels for all of the speakers within your setup.

THere are also DSP PROGRAMS of various descriptions that may also effect the audio even if a discrete multichannel format. The STRAIGHT mode also bypasses these programs.
 

LASound

Novice Member
Thanks Rambles. I just played a movie with the original 5.1 soundtrack in Straight mode and A/B'd it with the Surround Decoder mode and couldn't hear the difference. I wonder if when playing a movie "with" 5.1 capabilities, it plays the original and not the UpMix.
 

dante01

Distinguished Member
Thanks Rambles. I just played a movie with the original 5.1 soundtrack in Straight mode and A/B'd it with the Surround Decoder mode and couldn't hear the difference. I wonder if when playing a movie "with" 5.1 capabilities, it plays the original and not the UpMix.
THe upmixing modes only create pseudo channels for speakers that are lacking a discrete channel. The upmixing has no effect upon the discrete channels that are included with the audio format coming into the receiver.
 

LASound

Novice Member
Thanks Dante. That answered my question regarding why I'm hearing the original unaltered 5.1 sound track in Straight or Surround Decoder mode.
 

LASound

Novice Member
THe upmixing modes only create pseudo channels for speakers that are lacking a discrete channel. The upmixing has no effect upon the discrete channels that are included with the audio format coming into the receiver.
Got it. Thanks Dante and Rambles. You guys rock.
 

robdrums2097

Active Member
THe upmixing modes only create pseudo channels for speakers that are lacking a discrete channel. The upmixing has no effect upon the discrete channels that are included with the audio format coming into the receiver.
I run a Yamaha V681, in a 5.1.2 setup. I find that if I run the Surround Decoder and upmix even a 5.1 signal up to 7 channels, the volume & overall impact drops considerably. This is especially noticeable in the centre channel where dialogue sounds muffled. Is this just because it’s struggling for power running seven channels compared to five, or is the encoder reducing the impact of the discrete incoming channels by trying to spread it more thinly to give me emulated height channels to my Atmos modules?

My amp can’t put its DSP presets (like Standard, Sci-Fi etc) on top of the surround encoder (I think only the newer Aventage ones can do this), so I can only really run 7 channels on actual Straight Atmos signals or with the Surround Encoder. I’ve a nasty feeling, though, it sounds better in 5.1, especially for dialogue. Is the amp just not really up to powering all seven channels or is it the encoder diluting the sound?

Cheers

Rob
 

dante01

Distinguished Member
If the incoming audio is inclusive of a discrete centre channel then umixing shouldn'r be effecting that channel. After saying this, I have found Dolby Surround Upmixing to effect discrete channels and I assume that Dolby are in some way processing even the discrete channels in association with Dolby Surround? THe only instance where ths isn't apparent is if the source content is inclusive of Atmos metadata.

Yamaha's DSP Programs onboard your particular model would have to use NEO:6 upmixing. Your receiver hasn't the processing power to use Dolby Surround or Neural:X upmixing in conjunction with the DSP Programs and will not fascilitate applying the DSP Progrms to Atmos or DTS:X soundtracks. Only Yamaha's top three models all ow DSP Programs to be used in conjunction with Atmos or DTS:X.

As to the issues you are havng with dialogue, I'd maybe suggest that his is more likely to be due to the master volume levels you are listening at as oposed to their being any deficiency associated with your receiver and its ability to portray the centre channel? Your receiver calibrates itself in the same manner as any other receiver and the centre channel is calibrated to portray diaogue as it was recorded.
 

robdrums2097

Active Member
If the incoming audio is inclusive of a discrete centre channel then umixing shouldn'r be effecting that channel. After saying this, I have found Dolby Surround Upmixing to effect discrete channels and I assume that Dolby are in some way processing even the discrete channels in association with Dolby Surround? THe only instance where ths isn't apparent is if the source content is inclusive of Atmos metadata.

As to the issues you are havng with dialogue, I'd maybe suggest that his is more likely to be due to the master volume levels you are listening at as oposed to their being any deficiency associated with your receiver and its ability to portray the centre channel? Your receiver calibrates itself in the same manner as any other receiver and the centre channel is calibrated to portray diaogue as it was recorded.
Okay, could the trick be that you need to match the incoming signal to its relative encoder? As in Neo:X for DTS, Surround for Dolby signals? Surely not?

I was watching Ralph Breaks The Internet today on Blu Ray, and the DTS MA 5.1 soundtrack was a lot louder & more punchy, with clearer dialogue, in Straight than when I turned on Dolby Surround. I don’t think I experimented with Neo. I first noticed it when watching Strictly (which only gives out 2 channel PCM). I seem to recall Pro Logic being a bit like that.

Do I just crank it a bit more if I want to add the sixth & seventh channels, as it definitely does lower the overall impact, which must be affecting the discrete channels?

Rob
 

dante01

Distinguished Member
You'd not need any upmixing if dealing with Atmos or DTS:X.

All formats will automatically utilise the associated codec to decode that format and no, you do not need to select the codec to be used. Dolby Digital will for instance use the Dolby Digital codec on the receiver to decode the audio irrespective of what upmixing mode is selected. Dolby Digital will still be subject to Dolby Surround or Neural:X upmixing because Dolby Digital isn't an object based 3D immersive format such as Atmos or DTS:X.

Note that if you apply Neural:X to DD+ ot TrueHD encoded soundtracks inclusive of Atmos metadata then the AV receiver will ignore the metadata and you'd just get the DD+ or TrueHD audio aspect of the incoming audio plus Neural:X upmixing. Dolby Surround would however be negated by the presence of Atmos metadata so you'd get Atmos sans any upmixng.

Each source retains its own mode/upmixing configuration independently. I'd suggest engaging upmixing relative to your TV source, but maybe engage STRAIGHT relative to a Blu-ray source.


Do I just crank it a bit more if I want to add the sixth & seventh channels, as it definitely does lower the overall impact, which must be affecting the discrete channels?
Master volume levels don't vary depending upon the upmixing or number of cnannels being portrayed.

THe calibrated levels associated with each and every channel are still in effect so your speakers are still calibrated and the volume scale represented is still the same relative to reference scale.

I'd suggest it isn't a matter of the levels and simply a matter of the processing Dolby are enacting upon the audio relative to Dolby Surround upmixing? TRy using the Neural:X upmixing as an alternative. Many suggest this has more impact than Dolby Surround upmixing.

I'd even suggest using one of the receiver DSP Programs as opposed to the SUR.DECODER upmixing modes if wanting to engage the presence speakers with non Atmos or DTS:X encoded sources. I find the DSP Programs to be far more immersive than either Dolby Surround or Neural:X upmixing. You'll also find that the dimished impact you are experiencing isn't the case when engaging one of the DSP Programs. I use the STANDARD program relative to all my TV viewing. I do however have one of the older Yamaha models that still comes equipped with Pro Logic Cinema upmixing, but do choose to use NEO:^ upmixing in association with my STANDARD DSP configurations:

snapshot002.jpg



I'd be more inclined to use STRAIGHT whilst viewing Blu-rays though and tend to switch between the STANDARD DSP mode and STRAIGHT depending ipon the audio if and when using Netflix.

I'd also be more inlined to use STRAIGHT or even PURE DIRECT whilst listening to stereo music sources.
 
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cjlhessing

Novice Member
I have the Yamaha 865 and was having various issues with my sound - rear speakers and even sub making strange bass related noises during what would normally be silence (like the 3 seconds of a program’s black screen between a show intro and the action starting). Tried crossover and settings, spoke to all the manufactures concerned (kef, q acoustics and klipsch). Know what solved it? Turning the yamahas profile sound from surround decoder to straight. Suddenly no issues and still getting 5.1 where applicable across all connected devices. So, the processor definitely does something to sound even when it’s already DD 5.1. And I also notice volume is louder. Lesson here? Straight video and straight sound is always best.
 

Rambles

Distinguished Member
I have the Yamaha 865 and was having various issues with my sound - rear speakers and even sub making strange bass related noises during what would normally be silence (like the 3 seconds of a program’s black screen between a show intro and the action starting). Tried crossover and settings, spoke to all the manufactures concerned (kef, q acoustics and klipsch). Know what solved it? Turning the yamahas profile sound from surround decoder to straight. Suddenly no issues and still getting 5.1 where applicable across all connected devices. So, the processor definitely does something to sound even when it’s already DD 5.1. And I also notice volume is louder. Lesson here? Straight video and straight sound is always best.
It sounds like the surround decoder is not working properly, or implemented poorly by Yamaha. I don't get that issue in any of my set-ups and use upmixers for everything except 2 channel music.
 

cjlhessing

Novice Member
It sounds like the surround decoder is not working properly, or implemented poorly by Yamaha. I don't get that issue in any of my set-ups and use upmixers for everything except 2 channel music.
Yeah agreed, used to upmix a lot of stuff on my older onkyo but that was bought as a thx package so on one hand you couldn’t adjust things like crossover (physically or with gui) but things just worked lol.
Was considering just upgrading to the top level Arcam just to be rid of the noise issue but then suddenly found the cause of the audio issue.
 

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