Why do I need a Toslink cable? (1 Viewer)

[insomuchas]

Hi, Am in the process of setting up my first home theater & the receiver manual (Yamaha RX-V373) indicates that I need to connect the TV (Toshiba 32C120U) to the unit with both an HDMI cable & a digital optical cable. It is my understanding that the HDMI cable carries both video & audio, plus it looks to me like the optical audio out (Toslink) goes from the TV to the receiver. Why would I want the TV delivering audio to the receiver? My setup is a Roku device HDMI input into the receiver & the receiver then output (HDMI as well) to the TV. What does the Toslink gain me? When I stream music thru the tablet into the receiver (via HDMI) we hear sound from all speakers. Not really sure that is 5.1 surround tho. Doubt the tablet is capable of that. The real meat of my question is - I am not getting 5.1 from the Roku device. No sound from the surround speakers I do have the Roku setup in 720p & 5.1 surround. On the TV I have the HDMI audio mode set to auto per the instructions but a bit confused on the Digital Output Format: Dolby Digital & PCM both avail. Have tried both. When pressing the info button on the TV remote it displays PCM / 720p, therefore I have left it in that mode for the time being. Also disconnected the Toslink cable - did not help. So really I have two questions. 1) do I need a Toslink cable & why. 2) Have I got the HDMI audio mode set incorrectly? I suppose it's possible we just haven't watched anything in 5.1 surround yet? But we have some movies in mp4 format & they generate no sound from the rear speakers either. thank you for any help, insomuchas

 

[schan1269]

The only reason to do it is if you use OTA. http://antennaweb.org/

 

[Lars Larsen]

The toslink from the TV to the receiver would most likely be to output sound from your TV, to the speakers connected to your receiver. I believe newer TVs have a bi-directional HDMI connector that allows audio to be transmitted both ways, so in that case you wouldn't need the toslink.

 

[insomuchas]

Hi, had to Google OTA No Antenna. So it's working? Put Transformers: Dark Side of the Moon up from Amazon & all speakers are working. Perhaps we hadn't watched content in 5.1 surround yet. Just hooked it up last night & had only watched one movie & one TV show. So perhaps should have played with it some before posting. Now wonder if the movies I converted are all in stereo. Will have to go check my conversion settings. That would be a bummer. thanks

 

[schan1269]

With 2.0 content, you simply use DPL. And OTA is why I linked AntennaWeb.

 

[insomuchas]

Are your saying that Dolby Pro Logic transforms stereo into Surround Sound & DPL is the setting I would use during conversion?

 

[schan1269]

That was the reason it was created (almost)30 years ago.