digital audio?

[nurdonsite2]

ok im a total N00b in the audio section so i need some questions answred. what is digital audio? what are the advantages of it over regular (analog??) audio? will i be able to get digital audio out of my sound blaster live 5.1 with z640 speakers? or should i just stick to analog? plzz answer my questions and if im not making sense, point me in the right direction.

thanx.

[SpookyEddy]

One of the major advantages of using a digitally encoded source is that it allows you to apply error correction. As a result you should get a bit-by-bit perfect copy of the original audio data (although in practice this may well not be the case). This has atleast two major advantages over conventional analog recordings (off the top of my head)....

1) Any imperfections in the source media (within reason) won't adversly affect the sound quality.

2) You will reduce the amount of noise that gets amplified. The next stage in the audio chain is usually some kind of pre-amplification to provide some voltage gain. This is going to increase the magnitude of any noise as well as the audio signal you are interested in so the less noise at this stage the better.

However that all relates to analog Vs digital sources (aka vinyl vs CD etc). Sounds like you are talking about analog Vs digital outputs on a PC's audio card, in which case your source is digital regardless. One of the major advantages of using a digital output from a soundcard is that your PC is a very electronically noisy environment (lots of interference floating about) so if you can keep everything digital until you get some distance from the computer you should get a cleaner signal (atleast in theory). However using digital connections (especially optical) has its own pitfalls, not least of all timing issues (jitter etc).

Regards

ed

[shrae]

Advantage of having digital connections in a computer-receiver environment is allowing the better component to make the DAC (or at least just giving you the choice of which to use). For example, if you believe your soundcard has a better DAC then you can use that to decode and separate the channels to send to your receiver/speakers. If you believe your receiver (integrated or separate) has a better DAC, then send on the digital signal and let the receiver decode.

[davidamarkley]

Also, something to note here, that while Digital Out/SPDIF can be nice, your speaker system has to have digital inputs(whether it be SPDIF or optical). And another thing is that most cards/motherboards don't output digital as 5.1, most of the time it's Stereo PCM. So, you use the Dolby Surround. If the soundcard/motherboard say that it's Dolby Digital 5.1 or DTS Digital or something like that, then you can know that it's 5.1. Some motherboards that have onboard surround digital are the nForce2 boards with the SoundStorm onboard chip, and middle and up range cards normally have the Dolby Digital 5.1 built-in.

Your card, the Sound Blaster Live! 5.1 has built-in Dolby Digital AC-3 5.1 Playback, so it will output the Digital audio in surround format.

Others, such as the Sound Blaster Value 5.1, don't support Dolby Digital AC-3 5.1 Playback. Even though it says '5.1' in the model name, it only supports it in the analog outputs, the digital out is just Stereo PCM.

The only problem with what you're talking about is your speaker system. The Z-640's can't decode 5.1 digital audio. So, even if you can output it to the speakers, the speakers will only decode it as Stereo PCM. Here's an excerpt from a review on the speaker system:

From Virtual-Hideout.net
The Z-640s were made to be an affordable 5.1 system so that most anyone could enjoy 6-channel audio in their home in front of their computer or entertainment center. Logitech has worked hard to ensure they have systems available for each segment of the market - they don't just want to appeal to those who have the big bucks. It should be noted that the Z-640 will not decode a 5.1 signal; at its $99 USD (MSRP) price, this simply could not be included. The source you are attaching this system to (PC, DVD player, decoder) will have to be able to decode the signal and output six discrete channels that the Z-640 can output. Also included in the package (besides the sub and five satellites) were a small manual/installation guide and an video game console adapter.

Another advantage to digital is instead of having three wires going to your speaker system, you only have to have one. So, digital would be a nice way to go 'over the edge' in quality-wise enviroments, the problem is that you would need a better speaker system such as the Z-680. The only problem is that it costs a little more than the Z-640's...

In short, if you don't want to spend alot of money on a minute improvement, then get the Z-640's and just use the analog outputs/inputs.

David