AVS › AVS Forum › Audio › Audio theory, Setup and Chat › HELP: Surround truncated via HDMI
New Posts  All Forums:Forum Nav:

HELP: Surround truncated via HDMI

post #1 of 8
6/3/10 at 6:50am
Thread Starter 
Greetings,

I have a Panasonic 42PX80 TV and noticed something I'm hoping others can confirm and suggest fix, if possible: I have a PS3 (or any media device) and normally I set it to output audio via optical to receiver and hdmi video to the tv. I decided to try straight HDMI to tv and use the 42PX80's digital audio output to the receiver. After confirming all settings were correct in PS3 I switched it and found that the audio is truncated down to 2.1 rather than 5.1 or so surround. I tried fiddling with audio settings in TV but nothing helped so I put things back the to "normal" under the assumption the TV can not correctly pass thru the audio data stream to receiver. Is this a hardware limitation or perhaps there is a firmware fix for the TV? Perhaps there is an issue with the HDMI cable? I know the receiver is fine as 5.1/DTS works fine when audio is direct to the receiver and not passed thru TV. The end goal here is to utilize the three HDMI inputs on the TV and use the optical connection from it pass the surround to the receiver. My receiver is a Harman-Kardon/AVR-245

I hope some one has some insight to share because I'm at a loss.

NOTE: Normally I would input the devices via hdmi to the A/V receiver and output video to tv as a monitor. However, the H/K 245 has a known issue in transmitting video via hdmi but that shouldn't have anything to do with my passing thru digital audio from TV to the receivers digital audio input (tos).
Reply
Reply

AVS Top Picks

post #2 of 8
6/3/10 at 7:16am
This is expected, most TV's will only output 5.1 via the optical if you're tuning a channel with the internal tuner. HDMI pass-through is 'downrezzed' more often than not. My Samsung LN52A630 does the same thing. Frustrating I know!! Your best alternative is to get a A/V receiver with HDMI switching.
Reply
Reply
post #3 of 8
6/3/10 at 7:32am
Thread Starter 
crap. I was leaning towards getting a new A/V receiver any ways, so I guess this is a good reason to do so. Sigh. Oh well. Thank ya kindly. Stupid TVs; no point in having that digital output if is going to truncate in situations that one would intuitively think it would not.
Reply
Reply
post #4 of 8
6/3/10 at 7:46am
It has to do with HDCP - the TV will not allow audio sent from a HDMI cable to be sent back out via Optical.

There are a few TV's that somehow let it through, but it shouldn't.

I think it's stupid, but it is what it is.
Reply
Reply
post #5 of 8
6/3/10 at 11:35am
Quote:
Originally Posted by megaoptimus View Post

Stupid TVs; no point in having that digital output if is going to truncate in situations that one would intuitively think it would not.

Here's the actual purpose of the digital output on a TV: It's not there to allow TVs to serve as audio switchers. Rather, it's there for people who do not have cable or satellite set top boxes. If you use an off-air antenna or a direct cable feed, the digital output is the only way to feed DD 5.1 from HD channels to a sound system.

Quote:
Originally Posted by marlin29311 View Post

It has to do with HDCP - the TV will not allow audio sent from a HDMI cable to be sent back out via Optical.

There are a few TV's that somehow let it through, but it shouldn't.

I think it's stupid, but it is what it is.

I believe most TVs will output audio arriving over HDMI. But, the output is usually limited to stereo PCM. TVs are two channel devices and most instruct the attached set top box or disc player to downmix and send stereo. While a few TVs will pass DD 5.1 from attached equipment, I am not aware of any that pass DTS out their digital ports. Again, TVs are not designed to serve as audio switchers.
Reply
Reply
post #6 of 8
6/3/10 at 11:46am
Quote:
Originally Posted by BIslander View Post

Here's the actual purpose of the digital output on a TV: It's not there to allow TVs to serve as audio switchers. Rather, it's there for people who do not have cable or satellite set top boxes. If you use an off-air antenna or a direct cable feed, the digital output is the only way to feed DD 5.1 from HD channels to a sound system.


I believe most TVs will output audio arriving over HDMI. But, the output is usually limited to stereo PCM. TVs are two channel devices and most instruct the attached set top box or disc player to downmix and send stereo. While a few TVs will pass DD 5.1 from attached equipment, I am not aware of any that pass DTS out their digital ports. Again, TVs are not designed to serve as audio switchers.

That's what I meant to say, but it just never put it that way. You can't get 5.1 DD out of the optical out on the TV if you are using HDMI in. You will only get 2.0 stereo.
Reply
Reply
post #7 of 8
6/3/10 at 11:55am
Quote:
Originally Posted by marlin29311 View Post

That's what I meant to say, but it just never put it that way. You can't get 5.1 DD out of the optical out on the TV if you are using HDMI in. You will only get 2.0 stereo.

OK. But, I don't believe this is related to copy protection. There's no physical way to output multichannel lossless audio from a TV. The best you will ever get is a lossy output, which is not subject to copy protection.
Reply
Reply
post #8 of 8
6/3/10 at 12:12pm
Quote:
Originally Posted by BIslander View Post

OK. But, I don't believe this is related to copy protection. There's no physical way to output multichannel lossless audio from a TV. The best you will ever get is a lossy output, which is not subject to copy protection.

Understood, but the same thing happens even if you are using DD or DTS normally though HDMI, such as the case in an Xbox 360 or PS3 - you send DD 5.1 from your Xbox to your TV via HDMI, but the TV will not send DD 5.1 to the receiver via the optical.
Reply
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Audio theory, Setup and Chat

AVS Top Picks

AVS › AVS Forum › Audio › Audio theory, Setup and Chat › HELP: Surround truncated via HDMI