Hi, Big Picture Big Sound,
I have a Samsung LCD that has 2 HDMI inputs, an HD DIRECTV box, DVD player with HDMI connection and a receiver that I purchased but it does not have HDMI, since I was told I should keep all the video signals going straight to the tv and keep the audio signals just for speakers.
Therefore the DVD, DIRECT TV box are connected to the TV via HDMI. But I want to add a 5.1 surround sound so I have the Receiver that does not have HDMI connections therefore I was told I can have an optical (output) from the TV to go to the receiver. Is this the best connection in order to have all digital connections between the sources?
Unfortunately you got some bad advice about not needing HDMI audio support in your receiver. While standard optical digital (S/PDIF) connections do support the Dolby Digital signals in your set top box and DVD player, they do not support the advanced codecs of Blu-ray Disc, should you ever decide to upgrade -- this requires HDMI. Also, not all TVs support passthrough of the original Dolby Digital or DTS 5.1 signal from the source all the way to the external audio receiver so your desired connection (HDMI from satellite box and DVD player to TV, fiberoptic S/PDIF digital output from TV to receiver) actually may not be the best one.
I've tested this on a few TVs. A Panasonic TV I tested converted a 5.1-channel input signal from a cable box (connected via HDMI) into a 2-channel output. This makes sense when you consider that a TV only has two speakers, but it's unfortunate as it makes the connection a bit more complicated to a non-HDMI-equipped receiver. I've tested a Samsung TV that did pass through the Dolby Digital 5.1 signal coming in via HDMI to a fiberoptic output on the TV, maintaining the full 5.1-channel signal to the receiver. But this might not work for DTS as many TVs do not have built-in DTS decoders or DTS passthrough.
The HDMI-to-S/PDIF passthrough feature is one that doesn't even seem to be all that well documented in the commonly available TV specs. So unfortunately the only advice I can give you is to test it using a variety of signals, and look in your receiver's display to see what it is receiving. Use your DIRECTV DVR (if it is a DVR) to record a few HD movies from HBO (look for the Dolby Digital 5.1 indication at the beginning of the movie) or record any of a number of prime time shows (like "LOST" or "CSI") which are broadcast in Dolby Digital 5.1 sound. And pick out a few movies in Dolby Digital and in DTS on DVD, connect your components to your TV using HDMI and connect the TV's fiberoptic output to your receiver and see what you get on the receiver when playing these back.
The alternative (and probably better approach) is to connect the DIRECTV box and DVD player to your receiver directly using a coax or fiberoptic digital connection (using the HDMI cables for video only). This way you know the TV isn't going to change anything.
The simplest solution would have been to buy a receiver that supports HDMI audio decoding (not just "HDMI passthrough") and connect all sources to the receiver first, then from the receiver to the TV also using HDMI. With the digital signal carried over HDMI there really isn't going to be any video quality lost by routing the HDMI signal through the receiver first.
I hope that helps.