Dolby Pro Logic Question

U

udlilmike

Audiophyte
<font color='#000000'>My receiver, a sony strde845, has a dolby pro logic decoder.  How can I be sure that this is working properly?  My system sounds great while watching movies is dts or dolby digital but it doesn't sound all that good while watching broadcast television.  I only get sound coming out of the center channel.  Shouldn't the pro logic decoder give me 4 channels of sound?</font>
 
E

Eric

Audioholic
<font color='#000000'>Do you have digital cable or similar? Do you use a converter box?  I don’t believe you can get any surround info on a over the air broadcast.

Dolby Pro may be available over the RCA outputs of a standard cable box (not sure). Dolby Digital is normally available if you have a coax or optical output from the converter box.</font>
 
<font color='#000000'>I have had good luck with getting Dolby Pro logic from the digital cable box's coax feed.

In addition, even using coax from a digital cable box, you will only get Dolby Digital on certain stations, with certain programming (usually movie channels, and only on more recent movies.)

I'm not sure how well Dolby Pro Logic will show up on standard RCA outputs from a regular cable box, I would suspect that it would be intermittent.</font>
 
G

Guest

Guest
<font color='#000000'>Could this be caused by a mono source? &nbsp;Maybe some TV is still mono.</font>
 
Yamahaluver

Yamahaluver

Audioholic General
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Guest : <font color='#000000'>Could this be caused by a mono source? &nbsp;Maybe some TV is still mono.</font>
<font color='#0000FF'>Good point, most cable companies are guilty of sending out poor qualiy audio signals and sending mono signals is part of their operandi. I have fought many verbal battles with my local cable company in SI and to no avail.</font>
 
U

udlilmike

Audiophyte
<font color='#000000'>Thanks everyone for you replies to my question.
I think that my problem lies in my older tv.
Unfortunately, I'm still a little bit confused. &nbsp;I read on a site that the dolby pro logic format could be accessed while watching broadcast television. &nbsp;(others seem to imply that digital cable or digital satelite must be used) &nbsp;Have I been misinformed?
Here is the link to the site: http://electronics.howstuffworks.com/home-theater5.htm

Thanks for all your help.</font>
 
<font color='#000000'>Both... it has to be in the signal to be decoded. Often, cable companies will &quot;skimp out&quot; and give you crappy audio. Standard cable is capable of containing the signal, but it may vary from program to program, &nbsp;cable provider to cable provider...

VHS tapes can even carry Dolby Pro Logic.</font>
 
M

Mad Max

Audiophyte
<font color='#000000'>If you are only getting sound from center then i think your source is mono you should get some effects from any sterio source.
Max</font>
 
G

Guest

Guest
<font color='#000000'>I'm going to be a little against odds here, but Dolby Pro-Logic is not actually a source data stream format.  In  other words nothing is actually recorded in a &quot;Dolby Pro Logic format&quot;.

Essentially the source for Dolby Pro Logic is a simple analog stereo L&amp;R signal.  This stereo signal can be recorded with certain phasing and timing, but many stereo signals naturally have this anyway. The stereo input signal is simply run through what is called a matrix decoder (Dolby Pro Logic) that creates 5 separate channels of output.

The basic problem with Dolby Pro Logic is that many times the front soundstage simply collapses into the center channel like you describe.  This is very common.

To get a true multi-channel experience with stereo input signals (like TV or cable), you should demo Dolby Pro Logic II.

This is the next generation of matrix surround processing and does a superior job of making a stereo input signal sound just like a digital 5.1 signal.  Many users have said they can hardley tell the difference between a digital DD5.1 source and an analog stereo source processed with Dolby Pro Logic II.  Also,  Pro Logic II has adjustable parameters for stage width and front-to-back stage positioning.</font>
 
A

ahuebel

Audiophyte
I have a similar question to what has been addressed in this thread. I recently purchased a home theater system and have standard cable. I was wondering how to get surround sound on television shows or football games etc. I have RCA cables hooked from my TV audio out to video 1 audio IN on my receiver. I can set it to all channel stereo and it plays from the back speakers but I would like to get surround sound (and as I understand it, dolby pro logic is my only option). Can someone tell me if I need to configure my receiver a certain way? It is an ONKYO HT-S570. Thanks in advance.


Another thought/question. Does my television need to "support" dolby pro logic in any way?
 
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