Issue with Vizio VX32L's TOSLink output: no 5.1 sound :(.

Most TVs will not pass-through 5.1 audio via their optical output. The optical output will only pass 5.1 audio from the TV's OTA tuner.

Does your receiver have HDMI in and out?

I had a VX37L for awhile, I can tell you for a fact it doesn't pass through 5.1.

A programmable remote will solve that. They can do one button switching on both devices at the same time.

Get a Harmony remote. One button turns everything on and off and does all of the input selections on your devices. There's an easy, online interface to program your remote.

I picked up this model and ran my cable box and Blu Ray through the TV via HDMI and got the same results. I've been checking all of my settings on the AVR (Pioneer 411 VSX) to make sure it was not the problem. I wonder if Vizio has made a firmware fix for this issue??? Does not make sense to have HDMI and not have the TV pass through the audio when using PCM setting.

It does pass the audio as PCM. But, you won't get multichannel PCM. Optical doesn't support it and TVs don't support it.

Most TVs will only pass stereo PCM from externally attached components, although they will do DD 5.1 from the set's internal tuner. I'm not sure why you think this doesn't make sense. You are asking the TV to work like an audio receiver.

Yes. This is a feature, not a problem. To understand why: Consider a DVD encoded with 2.0 PCM and DTS5.1 (Default) soundtracks; to ensure playback on the TV's PCM/DolbyDigital 2.0 (only!) audio system, the DVD player uses ["2 channel only"] EDID info supplied by the TV over the HDMI handshake to correctly override the DVD's [Default] DTS5.1 soundtrack and instead pass the compatible 2.0 PCM soundtrack to the TV. [Your AVR is invisible in this process!]

Yeah...pretty much I can't think of a single TV that will output 5.1 through the optical unless it's coming from the internal tuner. Reason being is that either the TV (or the source) needs to downmix the audio to 2 channel to be fed to the TV's amplifiers and, as such, it is that 2 channel signal that the TV relays to the optical.

Honestly, I don't see why they don't just feed the DTS/DD stream they can receive from the source if they wanted to...but it's probably saving them a few bucks a set not to do this, so they don't. Not many people use it anyway...they just use their receiver to switch rather than the TV.

On a side-note...I honestly wish the industry would switch things around and allow the TV to be the switch rather than the receiver. There are many times when I'd rather not turn on the receiver and just listen through the TV's speakers because I don't care what the program sounds like. I suppose they invented ARC (audio-return-channel) and HDMI pass-through for this...but, for many, a simple optical out that passes 5.1 would be enough (if giving up the HD audio is acceptable) and there are many receivers that support neither ARC nor HDMI pass-through.

I don't think there were any TVs with with capability to decode/downmix DTS5.1 even announced prior to Fall 2010...?!


With the addition of integrated internet connectivity to (some) TVs, and the likelihood of future integrated 'tuners' for Broadcast-over-IP and/or HbbTV reception, the 'TV standards setters' would seem to have an opportunity to revisit that question "soon"!

Oh I'm sure you're right...and I'm even more sure they don't want to pay for licensing. Why should they, given a TV is stereo and it doesn't "need" that signal. That's why they make you feed it audio via 2-channel analog or via HDMI (with EDID saying 2 channel only please) and let the source (who paid for the license) take care of it. Especially so when very few users would ever appreciate it and the extra associated cost.

We shall see. I wonder if this is part the reason why ARC was developed, so through one single cable HDMI connection between the receiver and TV you can get audio/video to the TV and audio from the TV. Wonder how it'll all play out.

To explain more on why it does not make sense:

1. HDMI is design to allow the highest level of video and audio, and being a single cord connection makes it clean and simple for the average joe.

2. Blu Ray shines its best via HDMI and only upcoverts (the jury still out on that) if using HDMI. Unless you have a BDP that has analog outputs 5.1/7.1 you won't be able to hear the newest surround formats.

So with the industry that has sold us on the theory of HDMI will save us all in this new world of HD, you would think it would make sense that TV's would at least make their HDMI inputs passthrough to allow for the 5.1/7.1/ DD True HD/DTS/ DTS HD Master to be passed on to a AVR or AMP.

I have no problem going back to component cables and running my audio directly from the Cable box and BDP into my AVR to insure that I will be able to hear discrete channels formats. But it just goes to show how the industry has put the cart before the horse.

In my main viewing room, my AVR does all the work since it has HDMI inputs and out. But where I have this new 1080p LCD, in the bedroom I have an older AVR that does not have HDMI inputs, so this TV was a key piece that would allow me to view HDTV in full 1080i and Blu Ray in full 1080p just like my main system and what I thought would allow me to continue to hear full 5.1 discrete, instead of the softer DPLII. I called Vizio today and talked with a tech: He said that the optical out would support 5.1 if it was feed a true 5.1 signal, I challanged his position and place the TV in DD mode as he stated and turned to an HD channel w/5.1 and no change. I told the tech and he just said that my set does not support 5.1 and it just will do DD stereo and there is no firmware update to correct or upgrade.

recoveryone - This is not an HDMI issue. It's about how TVs work.

TVs are not surround sound processors and they are not AV receivers. They have digital audio outputs for just one purpose - so that people who use a set's internal tuner for reception can feed DD 5.1 to a sound system. TVs don't even have optical or coax inputs.

You should run HDMI from your cable box to your TV for video and optical or coax from the cable box to the AVR for audio.

the HDMI is that input you speak of, remember it carries video & audio all in one digital line/signal.


You missed the point, I already had that setup before, but my older Vizio only had one HDMI (No optical output) so there was no confusion about the audio being able to be passed through.

Sorry for me it is a HDMI via Optical issue, if the technology is failing to work as it should.

All I am saying is that the HDMI should have been a passthrough setup just as it is on some AVR's, I am not asking the TV to do any processing or decoding. I fully understand that the TV can only produce stereo from its own speakers, and if the optical can send out a 5.1 signal from its own tuner then it is capable of being used as a passthrough port from the HDMI. It should have been Incorporated in the design since the advantage of HDMI is to have one single line that can carry full 1080p video and 5.1 and higher audio. To my knowledge Optical can handle up to 7.1 discrete channels, and if it can only do the DD 5.1 that is better than DD 2.0

Generally, I think the theory behind it is to put the AVR between all your sources and TV, not the other way around.

you may be right, but unless you brought a new AVR within the last 3 years you are out of luck. People will buy a new or upgrade their TV sooner than buying an AVR. Surround sound has been around for over a decade and still the average Joe has no clue what is needed to get that 5.1 that is part of what is called HiDef. Many still depend on the weak sound of the built-in speakers of TV's or just maybe spend a few dollars on these new signal Bar (I call them wonder bars) speaker systems. I'm sure the ones on this forum are the ones in their own communities that others come to for information on their next purchased. But I still run into people that think that buying a HDTV is all that is needed to get HD, I gone over to their homes and see that they still are using single composite cable for the video, I"ve seen all of the speakers lined up in a row and they swear its setup correctly.


Now you all know if you read or see the advertisement for the latest LCD/LED or whatever and it talks about reproducing the highest level in Video and audio:

SRS TruSurround XT - VIZIO teams its stellar video technology with the best sound - SRS Labs TruSurround XT technology - giving you the best overall HDTV experience in the industry!

178 Degree Viewing Angle - Our LCD HDTV's deliver a viewing angle of up to 178 degrees, resulting in crisp and clear pictures that are visible from any seat in the house.

Integrated Digital/QAM television tuner - enjoy high definition and regular television programs with or without paid high definition service.

Zero Bright Defective Pixel Guarantee

programs are also broadcast in Dolby Digital 5.1 surround sound but, in order to take full advantage of this technology, it is necessary to have the right equipment.

Dolby technology was created by Dolby Laboratories, Inc., a company who are the most recognized provider of digital audio technology in the world today. In addition, Dolby Laboratories is known for its reliable and superior products, hence the reason that Dolby Digital Surround sound has become the defacto standard for High Definition TV.

It would be lovely if TVs worked the way you want. But, they don't. It has nothing to do with HDMI and everything to do with the way TVs are engineered.

I guess I wasn't clear enough there. I mentioned optical and coax as examples of the limited audio functionality in TVs. Digital audio has been around for decades, but it's never been added as an input for televisions. Doing so would make sets more complicated to operate and more expensive to build while providing no benefit in audio quality.


What do you think happens when you play a Blu-ray with a dts-MA audio track and feed the audio to a TV over HDMI? Currently, the TV tells the player to decode and downmix the track for output as stereo PCM. That assures the player will always send audio that the TV can handle. It's a simple interface that always works.

In your scenario, the player would need to send encoded DTS to the TV for it to pass along to the surround processor. But, how would you get sound for the TV speakers? TVs don't have DTS decoders. Are you suggesting that manufacturers add DTS decoders to their TVs?

This is just one example of why adding passthrough to TVs is not as simple as you seem to think. And, once again, it's about the way TVs are engineered, not about a failure of HDMI. You need to use your receiver, not your TV, for this kind of audio functionality. Since your AVR lacks HDMI, then your best option is to split the video and audio, using HDMI for video to the TV and optical or coax for audio to the receiver.

btw, optical is limited to 5.1 lossy encoded audio and stereo PCM.

If this is the case that your receiver is too old for HDMI audio, then the point of HDMI passthough on the TV seems to be a red herring.