# Digital audio pass-through - RCA LCD



## acollins (Feb 10, 2011)

Okay, long-time lurker but first post.

The audio pathways in my home theater are all digital. I have HDMI cables from a PS3, a HTPC, and a satellite box running into my RCA 42" LCD TV (L42FHD37).

The RCA TV has a TOSLINK digital audio out, so I run a S/PDIF cable to an RCA RX-7000 home theater receiver.

I've noticed that the digital audio, as it passes through the RCA TV, loses its encoding (whether it be Dolby Digital, DTS, whatever). This has made me wonder what's going on in the TV as the audio passes through and is switched from the HDMI digital audio to TOSLINK digital. Shouldn't this be a purely digital pass-through, with the digital audio being unaltered? Why is the encoding being stripped? Surely the TV isn't converting digital-to-analog and then analog-to-digital...

Everything sounds good, but I'd like to know that all the digital-to-analog conversion is happening in the receiver. I can't find anything on-line about this TV that's nearly technical enough to answer this question.

Any thoughts?


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## mechman (Feb 8, 2007)

Welcome to HTS. :wave: 

Have you tried connecting the audio directly to the receiver from the source instead of passing it through the TV?


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## tonyvdb (Sep 5, 2007)

It is normal for TVs to downgrade the signal to only 2.1 digital. It was decided by the powers that be that no signal can pass through a TV and be output to another device in 5.1 digital because of copy write concerns. You have to go directly through the receiver first to get the full 5.1 mix.


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## nholmes1 (Oct 7, 2010)

All good answers guys! Yes it is designed to do exactly what you are describing, bypass the TV and run straight to the receiver to get the audio in full surround sound.


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## Ray3 (Feb 4, 2008)

Yep, sources > receiver > TV and let the receiver do the heavy lifting. 

Since a PS3 is involved in the mix, a few words on audio and settings in the PS3 menu. The PS3 will not bitstream advanced audio formats to your receiver. It will not send advanced multi-channel formats over optical. It will decode all but DTS-HD and convert them to LPCM and pass that to your receiver via HDMI. It is rumored that DTS-HD MA support will be added in a future firmware update. In the interim, a 1.5mbps DTS track will be extracted from the DTS-HD MA source over optical or HDMI. Simple summary - use Bitstream with an optical connection, LPCM with HDMI to maximize your audio output from the PS3.


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