[therock003]

Which sound card would you recommend that will decode the audio files as best as possible so i can hook it up to an external dac/amp (rsa predator most preferably) and achieve maximum results?

 

[Hookem]

Really do not need a sound card if you have optical/spidi out on your motherboard.

If you need a "audiophile" pci stereo sound card 2 come to mind.

The ESI Juli and the Audiotrak Prodigy HD2.

I think florida music has the Audiotrak in stock right now...Kinda cool card...I have one coming or so they claim...Been waiting since May.

You can roll the opamps and it has a headphone amp...I know pci sound cards are not the way to go compared to a external USB, Coax, Optical DAC.

Just new to all this business and ordered the HD2 to check it out.

I looked at the RSA and it really did not give much in the way of spec's.

 

[dvessel]

Why would you need a sound card if you are using an external DAC? Decode audio files? Isn't that done through software > cpu?

edit:: never mind, Hookem already mentions this.

 

[deuginthesky]

Look more at sound card with a good digital output, some have no analog output.

 

[Redo]

ESI Juli@ is great for a digital transport

 

[Toe]

If all you're doing is using the digital output to hookup to an external DAC, you'd be just as well off with a $25 soundcard that supports bit-perfect output. A card with digital outs supported by the open source cmediadrivers would be fine. The only thing you really miss with those drivers is support for gaming APIs like EAX - if you don't game, then no worries.

As others were saying, the soundcard really doesn't play a part in 'decoding audio files'. If you're playing MP3s, the decoding is handled by whatever player you're using (Winamp, Itunes, etc.), and if you're sending, say, an AC-3 soundtrack from a DVD through the digital connection, the decoding is handled by the receiver at the other end of the line.

 

[therock003]

The mobo I'm planning to buy does have spdif support,but the rsa predator as far as i know doesn't.I think it takes sound from 3.5 mm jack.

Well i know decoding happens on the software side,when using audio from the computer,but that audio goes to the sound card and the sound card delivers it to an external audio device.

I guess the better the sound card,the better the audio signal transfer between the card and the device someones is using,or am i wrong here?

What i want is the signal to arrive to the external dac/amp with as less distortion as possible.And i mean whatever the transfer may be?(Analog/digital).

 

[dvessel]

What would be the point of an external DAC if it wasn't transfering in Digital.

CPU --usb--> Digital to Analog Converter | head amp --> headphone.

 

[therock003]

Oh dang that's y the rsa has the USB!I know what DAC means but i thought it got the sound from the input jack,i didn't realise it got it digitally from the USB, how silly of me!

1)So there's no need for a sound card at all?Even with a computer with no sound card,audio can just travel via USB to the DAC?

2)Is the quality the same as if the DAC used a bit-perfect spdif input to get audio?

 

[Toe]

There's several different setups that can get digital audio out of your system. If your motherboard's S/PDIF supports passing a bit-perfect digital signal, then there's really no reason for you to use anything else.

And yeah, if you use a USB-based system, it's basically just using a USB cable for the same purpose as an S/PDIF cable: getting a digital audio signal from point A to point B.

So to answer your questions:

1) Correct. When you're using a USB device, it effectively is your soundcard, so there's no need for an additional one. Note that a USB device can output either a digital signal (S/PDIF) or analog, depending on what you want it for.

2) One bit-perfect digital output is pretty much the same as another, whether it's coax S/PDIF, TOSLINK, or USB. Most of the 'quality' part comes at the DAC stage. With computer audio, the DAC can be inside the computer (either on the mobo or a PCI card), inside of a USB adapter, or in whatever's at the other end of the S/PDIF cable (standalone DAC, HT receiver, etc.) What's best just depends on what you buy, any of them can be pretty good.

 

[therock003]

I see.A couple of more things.

How do you know if an audio transfer is bit perfect,and what does that depend upon?

For example if i hook my pc to a dac via usb cable how do i know if the transfer is considered bit perfect?It's just a usb<->usb connection between PC and DAC.

Is it dependent upon the quality of the cable for it to be bit perfect?

Also what do you mean that a USB can transfer analog signal?You mean instead of transferring digital data it would transfer electricity?But what device would receive audio as electricity via usb?

 

[Toe]

The best way to test if you're getting bit-perfect output is to hook your computer's digital output up to a home theater receiver and play a DTS CD. If the receiver recognizes it as a DTS stream and plays it, then you've got proper bit-perfect output. If not, it'll either play noise or not play anything at all. Otherwise, just do some searching for comments posted by others who have the device you're thinking about getting, see if they can get bit-perfect output working.

Quote:

Is it dependent upon the quality of the cable for it to be bit perfect?

Doesn't matter at all.

Quote:

Also what do you mean that a USB can transfer analog signal?

The USB cable isn't transferring an analog signal. But the device at the other end of the cable (DAC/external soundcard/whatever you wanna call it) performs the conversion to analog, and thus will have some sort of analog outputs.

A diagram might help, here. The E-MU 0404 USB is somewhat popular around here, so I'll use it as an example.

Code:

[left]<computer> \ | | v |-- Digital stage <usb cable> | | / v <E-MU 0404> <---- Digital to analog conversion | v \ <RCA cable> | | |-- Analog stage v | <amplifier> /[/left]

Making any sense? You computer sends the audio data in digital format over a USB cable to a USB device, in this case to an E-MU 0404. The 0404 performs the digital to analog conversion, and ouputs the analog signal via its RCA jacks, or via its headphone jack.

I used the 0404 in that diagram, but it could be replaced with anything that has a USB input. The USB device could also have a built-in amplifier (the 0404 has a built-in headphone jack). It just depends what you buy and what you want it to do.

Another variant is where the USB device acts as a digital-to-digital converter. It takes the digital audio from the computer as input, via a USB cable, and outputs the digital audio data to an S/PDIF jack. Some people use a setup like this if they have a PC that doesn't have an S/PDIF jack and also have a DAC that doesn't have a USB input.

 

[therock003]

Of course it makes absolute sense,i just thought that usb could use to transfer analog signal directly if some internal DAC was used.

Anyway other than that,isnt the E-MU a DAC/AMP cause by the looks of the diagram it looks like it's just a DAC.

If it's an amp wouldn't it be DAC->AMP->RCA?

1)BTW what's the badwidth like?Would it work with USB 1.1,or if cable is used on a HUB where it has to share badwidth with other devices that are possibly connected?

2)Any other way to test if i achieve a bit perdect setting?Cause i dont have any DTS equipment.

 

[Toe]

The 0404 is a DAC/amp. I'm not sure if it has a plain line-out mode that bypasses any extra amplification or not.

1) The 0404 (and probably most other modern ones) is USB 2.0. You probably won't run into bandwidth issues.

2) I don't know of any other reliable methods for testing. There's a test clip called udial that can be used, although that tells you mainly if it's doing a poor job of resampling or if output is clipping. Not a real reliable indicator. I suppose if you have a digital input on your computer, you could try a loopback recording test with a DTS wav file. Never done that myself, though.