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Optical Digital cable Question

#1
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6/20/09 at 1:38pm
  • Joined: June 2009
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Hello Everyone,
I am trying to get 5.1 surround sound from my SONY digital TV. The TV is a 46" LCD, HD, KDL 46V2500 about 18 months old. The Receiver is a Sony, STR-DE545 with 5.1 surround sound capability. Outputs on rear of TV include the Optical Digital cable, and left and right channel jacks.

At present, I have left and right sound channels from TV to receiver, get decent sound thru FL, C, FR, but the rear L&R channels are combined into 1 channel and marked "S" on STR-DE545 receiver.

I recently bought the digital optical cable and connected it from the output on TV to TV/SAT input connection on back of receiver, but get no sound at all. Does anyone have any ideas how to make the digital optical cable work with this receiver ?

Thanks, Dave
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#2
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6/20/09 at 3:56pm
  • Joined: December 1969
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Re: Optical Digital cable Question

A couple of things:

1. You probably have to "tell" the receiver which video input the optical input "goes" with. They are usually assignable. Check the manual for directions.

2. What is your video source for the TV? Are you watching DVD, Blu Ray, cable, satellite or an antenna and the TV's internal tuner? This is important because on nearly every HDTV the digital output (coax or optical) only works for the TV's own internal tuner. For outside sources, you'll either get nothing at all or a downmix to 2 channel stereo or matrixed surround.

Regards,

Joe
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#3
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6/20/09 at 5:11pm
  • Joined: April 1999
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Re: Optical Digital cable Question

Make sure your "input mode" on the front of the receiver is set to "auto". Don't think it's assignable on this model.

According to the TV manual, you'll only get sound on the optical from digital channels. So this won't work if you have TV hooked up straight to cable, on an analog station (maybe it falls back to analog if you left the analog cables connected). You'll have to do a digital channel scan to try & find some digital channels. Give us more info on your source/provider and any set-top boxes you do or don't have.
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#4
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6/21/09 at 7:06am
  • Joined: June 2009
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Re: Optical Digital cable Question

Thanks guys ! You are a wealth of knowledge. Here is a little more information:

The television is connected to Comcast cable, which I believe is all digital now. That is my only TV source. My DVD source is an "upscaling" Sony which is also connected directly to the television. Both the Comcast cable box and Sony DVD are connected to the TV with HDMI cables. So, I have all audio coming from the TV to the receiver.

I get decent quality sound with just the left/right channel outputs on TV to the receivers left/right inputs. But I lack 5 channel separation. I get channel separation in left front, right front, and sound in both rear speakers (but the rear speakers sound mono). So, I hooked up the digital optical connection...it seemed so straight forward - just connect from the TV output to the receiver input. But I can't get any sound from that cable, even when the signal is assigned "auto" at receiver.

Interestingly, I tried connecting the DVD directly to the receiver via digital optical cable (I disconnected the audio signal from TV) and received sound. However the sound was about the same. Channel separation was identical to the signal received from the TV when it was connected to just the left/right audio jacks - still mono in rear left/right speakers.

It would seem to me that the problem is with the receiver set-up based on what you have both said, and my attempt to connect directly from DVD with the digital optical cable. I hope this information is helpful. I appreciated any thoughts you may have.

Thanks,
Dave
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#5
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6/21/09 at 9:55am
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Re: Optical Digital cable Question

Quote:
Originally Posted by dave95sps
My DVD source is an "upscaling" Sony which is also connected directly to the television. Both the Comcast cable box and Sony DVD are connected to the TV with HDMI cables. So, I have all audio coming from the TV to the receiver.

That isn't going to work. TV optical out doesn't relay full 5.1 from HDMI -> the optical; its main purpose is for the built-in tuner which you aren't using. At most you get 2.0 sound, and sometimes nothing. You'll have to connect both the DVD & cable box directly to the receiver using optical (or coax for the DVD) for the audio.

Quote:
Interestingly, I tried connecting the DVD directly to the receiver via digital optical cable (I disconnected the audio signal from TV) and received sound. However the sound was about the same. Channel separation was identical to the signal received from the TV when it was connected to just the left/right audio jacks - still mono in rear left/right speakers.

This is the right connection. Your results indicate that you don't have the DVD setup to output DD 5.1. Look in the DVD setup menu (usu hit "setup" or "menu" or something like that with no disc in player or at least stopped), audio setup, look for "DD" and "DTS" settings that toggle between "PCM" and "bitstream". Change these to "bitstream". (Note that not all DVDs are 5.1, some are 2.0 or even 1.0, it usually says on the box and in the DVD disc menu)

Cable box, you probably don't have to set anything, but do connect directly to the optical on the receiver. You won't get 5.1 on all channels/shows. 5.1 is most common on HD channels & premium movie channels. Not as common on SD basic cable channels.
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#6
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6/21/09 at 10:09am
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Re: Optical Digital cable Question

Quote:
Interestingly, I tried connecting the DVD directly to the receiver via digital optical cable (I disconnected the audio signal from TV) and received sound. However the sound was about the same. Channel separation was identical to the signal received from the TV when it was connected to just the left/right audio jacks - still mono in rear left/right speakers.

It could also be that you are expecting too much sound from your surrounds. In most movie soundtracks, the surrounds are not constantly producing sounds. Only when there is a need, like in an action scene. Sometimes this sound comes from both side surrounds (mono).
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#7
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6/21/09 at 10:48am
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Re: Optical Digital cable Question

Nah, I'm 99% sure I'm right. If he was getting DD 5.1 the receiver wouldn't display the mono surround. The single surround indicates old fashioned Pro-logic, from a stereo source. There are some DD 4.1 discs, mono surround, of older movies, but they're pretty rare. The way for him to know for sure is if the "dolby digital" light comes on the Sony with a 5.1 disc.
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#8
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6/21/09 at 2:52pm
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Re: Optical Digital cable Question

Quote:
Cable box, you probably don't have to set anything, but do connect directly to the optical on the receiver. You won't get 5.1 on all channels/shows. 5.1 is most common on HD channels & premium movie channels. Not as common on SD basic cable channels.

Actually, you do have to specifically enable DD 5.1 on the Scientific Atlanta digital boxes, HD boxes and HD DVRs I'm famliliar with. If Dave only has SD digital cable, none of his channels may be in DD 5.1. Depending on how the local cable company chooses to restransmit the signals, even the few SD channels where DD is available not come out of the wall that way.

Regards,

Joe
My Home Theater

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My niece, "Miss Goofy Face"
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