Optical and/or analog cables from TV??

[EJD]

Hey all-

First post here, and I wanted to check with you on the audio connections from my TV to receiver. I have a Samsung LCD, with both analog and digital (optical only) audio outs.

In order to listen to those HDTV shows with DD soundtracks, I believe I need to use the optical out to my receiver - correct? I don't believe the analog outs will allow the receiver to reproduce a DD soundtrack, but I may be mistaken.

If I do use the optical out - won't I also need the analog outs to send the sound from those TV shows that do not have a DD soundtrack? I don't believe that the optical out would send those shows, but again - I may be wrong.

Thanks

 

[MDS]

You are correct on all counts but do keep in mind that the optical out will only output digital signals that originate from the TV's internal tuner. You wouldn't use it if you have a cable box or satellite receiver.

 

[EJD]

Thanks for the quick response. Forgot to mention I'm only using broadcast HDTV - sounds like I'll be good.

 

[darien87]

You are correct on all counts but do keep in mind that the optical out will only output digital signals that originate from the TV's internal tuner. You wouldn't use it if you have a cable box or satellite receiver.

OK, what am I missing? I have a fiber optic cable going from my cable box directly to my receiver and the shows that are in 5.1 play in 5.1, while the others play in stereo. Why would the tuner from a TV be any different?

 

[agarwalro]

Some TV's may down mix the DD tracks to Stereo before they send it to the Optic out. So even if you receive DD audio signal, you will be sending only Stereo the the receiver/ processor if you use the TV for audio source.

 

[MDS]

OK, what am I missing? I have a fiber optic cable going from my cable box directly to my receiver and the shows that are in 5.1 play in 5.1, while the others play in stereo. Why would the tuner from a TV be any different?

I've never seen any TV that had a digital input, only a digital output and analog inputs/outputs. If you were to run analog cables from the cable box to the TV input and then the optical cable from the TV's digital output to the receiver you will get no sound because the TV will not convert analog to digital. That's all I was getting at because there is a misconception that you can connect a cable box, dvd player, etc directly to the TV and use the TV digital out to get to the receiver.

On the other hand if you use the TV tuner and connect the digital output to the receiver you will get DD and as Agarwalro said some TVs also have the option to downmix DD 5.1 to 2 channel PCM (or pass PCM to the digital out if that is the format the tuner received).

 

[EJD]

Some TV's may down mix the DD tracks to Stereo before they send it to the Optic out. So even if you receive DD audio signal, you will be sending only Stereo the the receiver/ processor if you use the TV for audio source.

How can you tell if your TV does this? (I can't seem to find any mention of it in my TV's manual)

If it does downmix the tracks to stereo, is there any benefit to using the optic out?

 

[MDS]

Some TVs have an option in the menu for DD or PCM. If you set it to PCM it will downmix DD 5.1 to 2 channel PCM. If you leave it set at DD, it will send the DD untouched (like 'bitstream' on a dvd player) and will also send PCM as-is without processing.

An easy way to tell how your TV behaves is to tune to a channel that is definitely in DD and then use the 'display' function of the receiver (that's what mine is called anyway) to show the input format. If for example, you tune to one of the Music Choice channels on digital cable, the receiver should indicate DD 2.0.