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Discussion Starter · #1 ·
Hi:


I have been listening to 2 channel stereo music with an Onkyo av receiver 797 with a Samsung dvd player M301. Recently I purchased additional speakers to take advantage of surround sound. I went to the manual for the receiver to check a few things and found that I am supposed to connect the dvd player and the receiver with a digital coaxial cable as well as regular analog cables which I have been using . What is the use of the digital cable? Actually, when I did so, the digital cable didn't transmit audio signal at all. Rather, it increased some kind of high pitch noise. I could notice it when the receiver's volume is just about half way up. That's pretty significant amount. So, my questions are:

1. Use of the digital coaxial cable

2. Is this noise normal?
 

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Not sure what exactly what the digital connection from DVD player to A/V receiver carries but it probably either carries the entireties of the rear channels' audio, or information to decode the rear channels from the front channels given the two analog left and right outputs.


If the cable has enough bandwidth and is of the proper impedance and has adequate shielding, it should not be the cause of noise.


Cables labeled as digital should have sufficient bandwidth and be of the proper impedance for digital signals. Except that the needs of digital versus analog signals is relative. The higher video frequencies encountered nowadays for analog HDTV not to mention the cable TV coax feed are much more demanding than lower frequency digital signals such as from a modem.


In practice, "digital" is often used on the labeling of a cable's package so the price charged by the manufacturer or store can be greater.


Video hints:
http://members.aol.com/ajaynejr/video.htm
 

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The digital audio cables (coax or optical) carry the digital audio bitstream which can be PCM stereo, Dolby Digital or DTS.


This is the preferred method for the best audio performance.


To use, make sure that on the DVD player, you set (via user setup menus) the audio output to "bitstream". This will direct audio out the digital connection.


On the receiver, set for Dolby Digital (or DTS for DVD's encoded with DTS) when watching DVD's. Also check that the receiver's DVD input setting is set to recognize (or assigned) the digital coaxial input.
 

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The musical info on the DVD is stored digitally. Your speakers need an analog signal. Two basic paths:


A) The DVD player converts the digital to analog and sends the analog signal to the receiver. If you only have a stereo analog connection between your player and receiver, you'll only be able to listed to DVD sound in stereo. If you have 5.1 analog connections between player and receiver, you can get full 5.1 sound. (Note that most, but not all DVD players have 5.1 analog out.)


B) The DVD player can send the digital signal off the DVD to the receiver, and let the receiver decode it to analog. The signal is sent along a single cable - either optical or COAX. Due to the simplicity of cabling, and since your receiver probably has a better decoder, this is the preferred method. In general, you only want a analog or a digital connection between player and reciever, not both.
 

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Discussion Starter · #5 ·
Thank you for your postings, especially Salmoneous:


I disconnected the analog cables and connected the digital cable. To my surprise, it worked this time! I just don't know what was wrong first time I tried. Anyway, thank you everbody for your thoughts.
 
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