Canadian TV, Computing and Home Theatre Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
321 Posts
Discussion Starter #1
My friend purchased this LCD TV and asked me for assistance in connecting it to an external stereo audio amplifier which only has analog inputs (RCA red and white sockets). Once we installed the patch cable (3.5 mm. miniature stereo/two RCA male), we were unable to get any audio signal to transfer from the TV to the external amplifier, in spite of setting the television's configuration menu to deliver a fixed audio out while muting the TV's internal speakers.

I called Sharp's telephone assistance line and the rep told me that whenever the TV is fed by a HDMI or components signal, the audio portion is prevented from being available as an analog audio out signal. The rep said that if the input signal to the TV enters via the 75 ohm coax cable connector, then the audio is outputted.

I have never heard of a case where it is necessary to block the low res analog audio signal originating from a digital source like a cable box or DVD disk. Can anyone confirm if what Sharp is claiming is accurate and reasonable as well? Thanks
 

·
Registered
Joined
·
1,058 Posts
The normal way of connecting audio is directly from the source (cable box or DVD player) to the amplifier rather than from the TV to the amplifier. The rep is likely correct audio would only be available from a coax input source.

Some typical connections are:

1. HDMI from cable box and DVD to AVR, and then HDMI from AVR to TV.
2. HDMI from cable box and DVD to TV, and digital audio from cable box and DVD to AVR.
3. Component video from cable box and DVD either directly to the TV or routed through the AVR, and digital audio from cable box and DVD to AVR.

In option 2 you may be able to substitute analog audio for digital audio.

Option 1 is the cleanest, and the others require fiddling with remote to make sure that all the right setting of audio and video from the same source. A programmable universal remote helps.

All of this is likely more than what you needed.
 

·
Registered
Joined
·
321 Posts
Discussion Starter #3
Thank you Bplayer for your suggestion.

Unfortunately, the external audio amplifer belonging to the owner of the TV is an old stereo receiver without a remote control nor an entry for digital SPDIF connection and no video switching facility.

So it made more sense to let the television switch between the cable box and the DVD player and control the audio volume using its remote rather than having to get off the sofa and push or turn a button on the receiver.

I can understand why most televisions will not pass through a numeric audio signal encoded within an HDMI bit stream and re-release it as a PCM signal out the back of the TV. Doing so would allow pirates to capture a high quality un-encrypted digital audio stream.

But in our case, we are only trying to intercept the low quality 2.0 analog audio signal that is enroute to the TV's internal loudspeakers. That hardly creates a threat to copyright protection.

If this TV had a jack for listening through external headphones while muting the internal speakers, then we could at least grab that analog signal and feed it into the stereo amplifier. But Sharp has no headphone jack and is being obstinate in not making the 2.0 analog signal available at the AUDIO OUTPUT jack.
 

·
Super Moderator
Joined
·
56,507 Posts
What you would like to have and what they do is often not the same. For example, here's the discussion on the limits on some TVs, as you mentioned for digital signals. I have not come across the same limitation on the analogue outs in my various optimizations, but it appears this TV has them, unless you're missing something.

http://www.digitalhome.ca/forum/showthread.php?t=17870 Read the Bolding.

Now, there may be another option. Many Sharps have a pair of analogue audio inputs associated with one HDMI input and also allow you to chose (via the user menu - under HDMI or audio) whether to use those analogue audio inputs. If you can use those inputs instead of the HDMI audio, the TV may "pass" that signal out the analogue outs.

If that isn't available, use component video and analogue audio? TVs usually just don't work well for switchers.

If all fails, get a new AVR - you can probably pick up a used one with digital inputs, surround sound, etc for $100 or less and connect directly to the AVR instead of through the TV, the way it's supposed to be done.
 

·
Registered
Joined
·
321 Posts
Discussion Starter #5
Thanks 57 for the update.

In fact this Sharp TV has 4 HDMI inputs and number 4 has the option of a separate analog stereo audio input (via 3.5 mm. mini plug). In the menu there is a way to configure the audio portion of port 4 as "HDMI+analog".

Should the audio suddenly get passed through to the AUDIO OUT jack on the back, then I would further hope that what the call center rep. said about the audio input for a components connection not being passed through would have been an error on her part.

I'll ask the owner of the TV to buy an additional audio patch cable and try your suggestion.

Thanks again.
 

·
Super Moderator
Joined
·
56,507 Posts
One "test" would be to connect the component video/ regular analogue audio cables temporarily, tune to that input and see if the audio flows through the TV with the external audio, internal speakers off option...

No guarantee of course since the HDMI port with the analogue input could still behave differently...
 

·
Registered
Joined
·
321 Posts
Discussion Starter #7
Thanks 57,

I have invited the owner of the TV to continue the project.

We need to determine

1) that the analog audio from a component or composite input to the TV is passed through.
2) that the analog audio part of the port 4 tandem HDMI/Analog input from the SA8300HD+ is also passed through.
3) that the SA8300HD+ does not disable its analog audio out the same way it disables its components out whenever a TV is connected to it by HDMI.

On my own SA8300HD, I have confirmed that the cable box's analog outputs are indeed maintained even if the components output are disabled when a TV is connected using the HDMI cable.

So it remains to be seen if the first two tests will succeed like the 3rd. test did.

I will post results when the TV owner gets around to buying another necessary 3.5 mm. to RCA patch cable.

Thanks again.
 

·
Super Moderator
Joined
·
56,507 Posts
One more test if you like:

Connect the STB to the TV via RF-coax. Go to TV input, Tune to Channel 3 (that should tune the output of the STB). This will be poor PQ and mono sound on the TV speakers, but the audio should go to the output when properly configured for external audio...

That should confirm that you're doing the user menu configuration properly for external audio.

The analogue audio output from STBs and DVD players is always live (haven't encountered such a device where it isn't). It certainly is for the 8300.
 

·
Registered
Joined
·
321 Posts
Discussion Starter #9
Connect the STB to the TV via RF-coax. Go to TV input, Tune to Channel 3 (that should tune the output of the STB). This will be poor PQ and mono sound on the TV speakers, but the audio should go to the output when properly configured for external audio...

That should confirm that you're doing the user menu configuration properly for external audio.
The cable out of the STB is low def NTSC channel 3 as you state. The call rep at Sharp claims that an ATSC signal fed by coax from an OTA antenna to the TV will have its audio portion passed through the TV.

Even if either of these two scenarios works, because of, or in spite of the proper TV configuration menu setup, we still need to be able to get the TV's HDMI port 4 to pass within the TV the tandem analog audio signal entering via the separate 3.5 mm. patch cable.

I live 50 km. away from the TV so unfortunately I am not in a easy position to do a battery of tests.

Stay tuned....

Thanks to the help provided by posts in this thread, we have the confidence to continue.
 

·
Super Moderator
Joined
·
56,507 Posts
I believe the Sharp rep may be mistaken. He may be confusing the fact that the optical output on the TVs is designed for the internal tuner to send DD5.1 signals externally, with simply sending audio out the analogue output, but then again, it could be one of those "weird situations" where this is indeed the case (no passthrough at all)

So far, whenever I've been requested to do this by the client, it has worked (using the TV as a switch) and sending out analogue audio. Of course the limitation is that you don't get digital audio, but most customers requesting this are using an older analogue receiver like yours is...

Good Luck.
 

·
Registered
Joined
·
321 Posts
Discussion Starter #11
Page 15 of the user manual suggests that there are no caveats when using the analog audio out. The call rep agreed that it would be wise to add the restrictions to their next edition of the user manual.

However on the same page, the user manual does site a caveat when using the digital audio out (optical fiber):

"Depending on the connected equipment, audio will not output from the DIGITAL AUDIO OUTPUT terminal in HDMI connection. In this case, set the audio format of the connected equipment to PCM, 32/44.1/48 kHz."

We assume that in this case the HDMI connection is upstream of the TV.

In the worse case, it appears that in order for the TV to pass through audio originating from a STB or DVD player using HDMI, the STB or DVD player must be configured to replace Dolby TrueHD, DTS-HS Master Audio or Dolby Digital with a more simpler PCM bitstream.

And since the TV has no digital audio input, this down-rezed digital audio would have to be sent over the HDMI cable. Not sure that the cable box can do all that.
 

·
Super Moderator
Joined
·
56,507 Posts
Most cable STBs do have a PCM or "other" setting when using the digital (optical/coaxial audio) outputs, however, that option may not be available when using the HDMI output. The TV should be able to handle incoming DD5.1, even if it gets "downconverted" to PCM or analogue audio by the TV. There are a few rare TVs that have no ouput on the optical out unless using the internal tuner as discussed in the FAQ I provided. Some (newer) TVs will even passthrough HDMI DD5.1 to optical out DD5.1, although most do not. It's all model specific unfortunately and the OMs are rarely much assistance.
 

·
Registered
Joined
·
321 Posts
Discussion Starter #13
Neither our receiver nor our TV has any input for digital audio, so the TV can only get audio via HDMI or the 3.5 mm. mini stereo patch cable.

We already know that the TV blocks the pass-through of DD5.1 entering it on HDMI, so we hope that it will allow analog audio from the STB to pass-through to the stereo receiver.

Thanks again 57 for your comments.
 
1 - 13 of 13 Posts
Top