What usage ?

[jayantadak]

Audio decoder

In one of the posts I happened to read was that one of our members wanted the TV sound to be more defined and acoustically better through his optical out connection. Some members had suggested for an audio device which goes by the name of : "5.1/2.1Channel AC3/DTS Audio Gear Digital Surround Sound Rush Decoder Theater"

I googled for the device where it was mentioned that: "It can decode Dolby AC3/DTS audio and output 5.1 analog audio at the same time."

On digging further I came across the details that: "The DTS/AC-3 audio decoder is to convert the optical, coaxial (LPCM included), or digital audio signal from computer, PC sound card, PS3, XBOX360, Blue-ray, DVD players, HD set-top boxes, HD players into 5.1 analog signal."

Please let me know the meaning of the term: CONVERTING THE DIGITAL AUDIO SIGNALS to 5.1 or 2.1 ANALOG SIGNALS. I had the impression( may be it's wrong) that 5.1 audio signal itself is a digital signal which can be either optical or coaxial. Now 'Digital' is opposed to 'Analogue' In other words '5.1' and 'Analog' appear to be contradictory, which also means '5.1 digita'l is different from '5.1 analogue', which is something I cannot understand. So our friend's set up- who is need of enhanced TV sound- would be something like this: TV's optical out>The above digital audio converter>external speakers. But what about the amplification, would an amplifier be required between the audio convertor and external speakers.

If at all an amplifier is required, then it is easier to go for an AVR or a soundbar which has an inbuilt decoder instead of adding an external decoding device. Please clear my confusion and suggest the best possible combo.

As a matter of fact, I too am in need of an enhanced TV sound, though I am having a home theatre set up, I would like to get a decent TV sound for casual listening (serials, sports) through a simple connection without involving the home theater, where I have put on the AVR

 

[baijuxavior]

A digital signal can have audio in 5.1 or 2 channel format and it needs only a single cable like coaxial or optical to transmit this signal. Dolby Digital (AC3) and DTS are the two common technologies used in surround sound. Now this digital signal need to be converted to analog format for further amplification by an amplifier. The device that does this conversion is called a DAC (Digital to Analog Converter). Some DACs have only two channel output while some others have 5.1 out. Now you don't need a DAC if your amplifier can decode the signal. But not all amps have built-in decoder for this. As an example you may have seen those cheap Chinese 5.1 home theater boxes. These have no built-in decoder for digital signal. They provide six analog inputs to get the surround signal. So obviously you need a decoder that will convert the digital signal to six channels (5.1). From this decoder you use three 2 RCA cables to the amplifier to get 5.1 sound. There are surround amplifiers that accept digital signals from multiple sources, decode them, amplify them and reproduce them for your listening. These amps are usually called AVRs. So if you have an AVR based HT system then you don't need any of those decoders. But if you have those Chinese boxes then you need a decoder.