Saturday, May 24, 2008

Digital coaxial Vs Analog Audio cables for Home Theater setup

Digital Coaxial technology Analog cable technology
I order to make sure that I am getting the best Audio output form my Onkyo TXSR503 A/V Receiver (Home theater setup). I started exploring about all audio input supported by my Receiver. There are basically three inputs and I think it’s true for most of the receivers now a days. Digital, Analog and Optical. From the beginning I have been using the standard analog (Left/Right) kind.

So I thought let’s see if it makes any difference by switching to digital Coaxial. Before going ahead with my purchase of a brand new Digital cable. I just wanted to make sure if it’s worth the investment because these cables are expensive as compared to the regular ones. A nice and cheap would cost your around 1000 Rs (25$ apx). So I Started reading more about the digital cables and what value would it add to my kind of setup?

Surprisingly, I got very conflicting opinions on this matter. But after reading all the information and experiences shared by people online. I concluded that it won’t make a noticeable difference in my case. Here is a very interesting explanation I read on one of the forums online and it actually convinced me with my decision to hold back on the purchase:
“At least in theory, there is a difference between the RCA cable and the coaxial cable. Since you sound like you might be interested in a scientific explanation, I thought I should provide one. You do understand the basics, so I’ll skip that. What is important though is that digital signal, the succession of voltage changes from 5V to 0V like you said, is after all an electric signal. As such, it is characterized by a frequency spectrum, or bandwidth. If the digital signal would be a perfect alternation of 0’s and 1’s (0,1,0,1,0,1), then your electric signal could be looked at – in very ideal terms – as a sine, or in other words one single frequency.
However, since the digital signal looks kind of rectangular, there is more than one frequency in there. If you looked at the frequency distribution of a digital signal which consists of a perfect alternation of 0’s and 1’s, you will see that there is a main frequency, and to the left and right other frequencies of decreasing amplitude. For example, the predominant frequency could be centered at 5 MHz, and around it, decreasing, other frequencies at 4 and 6 MHz, 3 and 7 MHz, and so on. This tends to get kind of convoluted, but what I am driving at is the fact that since in real life the digital signal is never a perfect alternation of 0’s and 1’s, there will always be a frequency distribution (spectrum) associated with a digital signal, or a bandwidth.
Now, the bandwidth of a digital signal varies significantly. Some media carry this signal better than others. There is a reason why your antenna cable is coaxial and not RCA, and that is simply the fact that coaxial cable carries better wide spectrum signals at relatively longer distances.
What that means is that some media will simply not be able to carry the whole frequency spectrum, acting pretty much like a filter, cutting out some of the frequencies, and this has an impact on how the signal will look on the receiver side.
That said, going back to the RCA vs. coaxial question, the truth is that for short distances – a few feet – there will not be a lot of loss of information due to this filtering (or in other words the receiver’s inability to decode correctly 1’s and 0’s), but there will be some nonetheless. Here is where another feature kicks in, and that is the advanced coding algorithms. With pretty much all modern telecommunication technologies, when digital information is transmitted from point A to point B, that information is ran through some coding engines which are based on some algorithms that allow the receiving end to decode correctly the transmitted signal even if there is loss of bits on the path. Most of the times, this makes the loss of information on the path imperceptible for the human ear or eye. Although is may sound kind of out there, this is the way this stuff works. For example, information on your CD’s is coded the same way, such that if the laser skips a block of bits, the decoding engine (algorithm) can still rebuild the original bit succession. I am not sure if all this brought any light or confused you even more, but the bottom line is, for short distances, up to a few feet, there is no difference between the RCA and coaxial cables, but beyond that, the signal may become so garbled that even the decoding algorithms cannot pull it through. Therefore, you may want to consider a coaxial cable if you need to carry 5.1 Digital signal more than 3-5 feet away.”


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5 Comments:

At June 14, 2010 at 4:11 AM , Blogger Thomas said...

As the home theater comes on to the scene and becomes more and more popular, manufactures of Home Theater Seating are producing seating that provides all of the functions that are common to entertainment room furniture with one very unique bonus.

 
At October 30, 2010 at 9:29 AM , Blogger Alex said...

Home theater is today entertainment.

- resume

 
At November 1, 2010 at 5:44 AM , Blogger Joseph Hogan Wilks said...

Home theater systems seem like they are getting much better as the months go by. I would hate to pick one up and have another come out with thousands more features for the same price. I suppose as long as it sounds good, that is really all that matters. But hey as long as i am not using the old analog cable connection from my old Yamaha receiver, I should get clearer sound? In a 10x10 foot room would I hear a noticeable difference between the connections?

 
At November 19, 2010 at 9:09 PM , Blogger geo said...

In my sony dvd the 5.1 output is digital(coaxial output).

I made 5.1 home theatre with analog inputs.

Can i connect digital dvd o/p into analog home theatre input??

Plz mail ur answer.

Geofrancis993@gmail.com

 
At November 19, 2010 at 9:12 PM , Blogger geo said...

In my sony dvd the 5.1 output is digital(coaxial output).

I made 5.1 home theatre with analog inputs.

Can i connect digital dvd o/p into analog home theatre input??

 

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