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I thought this might be useful to anybody with the same requirements as I had.


I have a lounge with 5.1 sound from a Denon amplifier. Everything is connected via HDMI.

I wanted to connect my kitchen TV up using HDMI because it retains the quality and feeding an HDMI cable to it was easy.

So I wanted to retain 5.1 sound in the lounge and only have stereo in the kitchen.

Sounds simple ?


No it ain't because HDMI sets everything to the lowest common denominator (for a variety of reasons) with the end result being that with the HDMI cable connected (just connected only) and the TV in the kitchen off it forces the sound in the lounge to drop to stereo. The only way to keep 5.1 was to unplug the HDMI cable in the kitchen. Apparently even in standby HDMI circuitry is powered thus affecting the handshaking even though the HDMI input in the kitchen TV isn't even selected.


So it means you have to do the following to make this work.-


1. Stop the HDMI in the kitchen feeding anything back to receiver in the lounge

2. Find a way of generating stereo from 5.1 audio

3. Inject this back into the HDMI cable going to the kitchen.


My solution so far is only partial but read on.

To break HDMI I passed the signal first through an HDMI to DVI cable adapter. This signal then went into a powered box which converts DVI into HDMI and onto the kitchen TV. And now the sound in the lounge stays 5.1. So the DVI in the middle stops the HDMI handshaking interefering with the audio. DVI video is supposed to be the same quality as HDMI hence the simplicity of the cable. But it doesn't incorporate the HDMI handshaking circuitry hence its use.

I haven't got sound sorted yet because I have to build something first. The DVI conversion box also accepts a Digital coax input. So the last 2 pieces required is a conversion box for L&R stereo to digital coax which I can source so this will pass a stereo coax signal and add it to the HDMI to the kitchen TV.

The trickiest bit is how to convert 5.1 audio into stereo without losing any serious information. All potential outputs from the amp don't work when the amp is decoding 5.1. They are either/or but not both (anti-piracy anybody). But I do have seperate analog audio outputs for each amp in case I want to add larger power amps. So I will build a simple mixer taking 6 outputs and converting them into the 2 stereo outputs for second converter. With individual volume controls on each I can balance the surround and bass to levels suitable for the TV.

I may initially just try the L & R channel signals into the analog to coax converter. Perhaps my wife won't detect the difference ?


The 2 decoder boxes and DVI cable only came to about $80 odd and apart from labour the mixer will only cost about $30 in parts.

You should be able to expand the outlets to a number of stereo only TVs around the house without affecting the ability to play 5.1 audio in the main lounge area which was my goal.


To find the components search on the following -

analog to digital coax (DL-LINK TS-AD01 or 3089)

dvi to HDMI cable

dvi + audio to HDMI converter (this seems to be a standard device and they all look the same)

The audio mixer I cannot help you with. The circuitry I have so far is really simple. There are a number of boxes that do do this job but they are either 1U rack sized or designed for studio use so physically aren't very useful BUT should do the job without having to build something.

The boxes came from DX.com and the cable I sourced locally.
 

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Interesting. I thought HDMI carried the a/v as a complex single signal and can't be separated. DVI is video only. So if an audio signal is sent to a DVI cable, the only thing that passes thru is the video, audio is lost. Learn something every day.
 

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Quote:
Originally Posted by Otto Pylot  /t/1525224/how-i-almost-broke-hdmi-but-it-now-does-what-i-want#post_24553418


So if an audio signal is sent to a DVI cable, the only thing that passes thru is the video, audio is lost.
No.
 

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^^^ oh, ok. I thought DVI was just the video stream only, no audio. Good to know.
 

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DVI doesn't support audio. But if you output video and audio through an HDMI port to a cable with a DVI connector on the other end, both the video and the audio arrive at the other end. Think about it. How is a dumb cable going to change the information transmitted over it?
 

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Well, that's the point. I didn't think about it, at least not all the way thru. Thanks.
 

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Quote:
Originally Posted by Colm  /t/1525224/how-i-almost-broke-hdmi-but-it-now-does-what-i-want#post_24554194


DVI doesn't support audio. But if you output video and audio through an HDMI port to a cable with a DVI connector on the other end, both the video and the audio arrive at the other end. Think about it. How is a dumb cable going to change the information transmitted over it?
I don't think that would be the case. I think the pins/connections used to transmit audio simply wouldn't be incorporated into an HDMI to DVI cable. I mean, out of what pins on the DVI end would the audio come out of? And if that were the case, an HDMI to DVI cable could then be connected to a DVI to HDMI cable (with an adapter in between) and still retain the audio signal... But I'm pretty certain that wouldn't be the case.
 

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Chris, I've considered a similar setup, but the loss of audio/audio control has stopped me. Removing HDMI handshakes from certain parts of my HDMI setup would solve so many of my current HDMI issues. I've considered getting devices like this HDMI to HDMI+SPDIF/RCA or this one , but then I'd have to setup a separate receiver in the kitchen/secondary room to handle the audio coming in... which I may end up doing with my old reciever that's just gathering dust in the closet. It just simply isn't as clean as having the audio come in on the TV, and be able to control volume with just one remote, plus the wasted space in having a receiver and 5 speakers in the kitchen/secondary room could be annoying.


I don't know if it would help you, but this should convert digital 5.1 to RCA stereo... My biggest concern would be about the audio delay from the conversion (as the reviewers mention).


I'm really looking forward to see what solutions you come up with!
 
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