[Phelonious Ponk]

Quote:

Indeed no magic here, but we should not oversimplify a complex matter. The problem with SPDIF interfaces is actually jitter. What you wrote applies to file transfers, not time-critical sound reproduction. It is of paramount importance (for sound quality) not only to get all the right bits, but also in the right order.

Until the data gets to the DAC and gets converted to analog, what we're talking about is a file transfer. Jitter is an issue in both usb and spdif, but it is not one that a competent, modern DAC cannot handle. And by the way, jitter has nothing to do with the right order of anything.

P

 

[Emokid]

I compared USB and spdif on STADEDAC, no doubt spdif does sound better, unfortunately difference between onboard spdif and HiFace spdif out is not so obvious on my system.

 

[Phelonious Ponk]

Quote:

I talked to Benchmark about my DAC1-Pre and they recommended the USB over SPDIF. It's apparently optomized for that connection.

Interesting. One of their design engineers told a friend of mine that they couldn't detect an audible difference between USB and spdif. Of all that is being said in this thread, I think this is closest to the truth...

Quote:

They should sound very similar. USB and SPDIF both transmit 0s and 1s.

...and this is the best advice...

Quote:

try both and see which one sounds better to you.

But if both are properly implemented, there should be, as the Benchmark engineer above noted, no audible difference. Just a moment's thought debunks this myth. Benchmark is a pro audio company. Why would they optimize their DAC for a computer interface that is among the least likely to be used in the studio? I don't doubt the poster above was told that...probably by a marketing guy who was telling him his DAC was optimized for the interface he was using...

P

 

[RonaldDumsfeld]

I'm afraid I don't really understand what is going on here.

Can someone help me out please and point me in the direction of some good information?

Why is it a good idea to output digital audio files to something like the HiFace, convert it to S/PDIF then pass it on to another DAC where it gets converted to analogue?

Why not send the original signal direct to a single DAC and have everything done in one operation? What's the theoretical advantage in doing it in 2 discrete steps?

Thanks?

 

[ROBSCIX]

The Hiface or other devices like it, will improve the signal and help minimize jitter. Atleast that is the idea behind them anyway, as people have varying opinion on those devices.

 

[RonaldDumsfeld]

kk. thanks for trying.

Still don't get it though.

How do you get a signal degradation and/or jitter into a digital file in the first place? Your audio app. outputs a sequence of 0s & 1s. It does that as a file transfer. Not in real time. Like 24 bits once every 44k times a second and up. Surely the DAC itself deals with any timing issues that might occur.

I realise this might not be easy to answer so a reference might help.

Forgive my ignorance on these matters but I'm a rtd. software engineer. I've always worked under the assumption that a digital data file gets to it's destination either bit perfect or in totally useless condition. What's different about audio data?

 

[ROBSCIX]

Jitter is basically timing errors. They can be introduced at a number of places.
Yes, from the software side, everything should be fine... When we hit the hardware side though, you start getting into sloppy timgin circuits, component tolerances and low grade transmitters and receivers, noise, EMI, RFI...lots of badness!

However, this is the point that seems to be the big debate, is the jitter audible?
Does any of these errors even matter to the end audio quality? Some say yes and some say no.
Not to mention there are about 10 different types.

Personally, I prefer to stay out of the debate but just trying to offer some information.

 

[Phelonious Ponk]

Quote:

How do you get a signal degradation and/or jitter into a digital file in the first place? Your audio app. outputs a sequence of 0s & 1s. It does that as a file transfer. Not in real time. Like 24 bits once every 44k times a second and up. Surely the DAC itself deals with any timing issues that might occur.

Ronald,

You don't need a better source of information, you are a better source of information. There's nothing here to get that you don't get, except that some companies trade in selling the further reduction of a distortion (jitter) that is already reduced below audible levels by competent DACs in very common consumer devices, and they have a gaggle of followers who believe their systems or their ears are so special that they can hear this jitter which is well below the threshold of audibility of instruments that hear more than any human can.

Welcome to audiophilia.

P

 

[audiofil]

Just out of curiosity: what do you think about the differences between USB and coaxial SPDIF ?

 

[RonaldDumsfeld]

Thanks guys. Slow today but I think I've got it now.

Some of you guys started using the co-ax or optical S/PDIF out because you wanted to by-pass as much as possible the on board DAC on your mobo or gamer grade sound card.

So something like the HiFace allows you to continue to use legacy soundcard/DAcs and/or a legacy paradigm.

A HiFace is at best irrelevant if you already own an up-to-date DAC chip in a device connected via Firewire or USB 2.0.

Phew. That was a struggle. I thought I might be missing out on something.

 

[ROBSCIX]

You are still a bit off..

Many people use S/Pdif coax and optical because it will bypass the onboard DAC of the mobo audio or the soundcards DAC. Depending on the card though all the features of the soundcard will stillbe available through the DAC.

People use the Hiface because it produces a higher quality signal (their words not mine) in comparison to a crappy onboard S/Pdif output etc. It has nothing to do with a soudncard/DAC and or legacy paradigm.

There are many USB to S/Pdif converters out there for this task.
They can still be used with an up-to-date DAC provided it has coaxial or BNC input.
If you want to use Firewire or USB for conenction that is fine. Some prefer to go with S/pdif instead.

 

[5aces]

If I were to go with USB on a laptop,it would be to get uncompressed sound in the form of PCM at up to 24bit resolution and 192kHz sampling rate.

Even audiophiles who think the sound of old vinyl records still beats the digitized CD versions concede that at that resolution and sampling rate there is no way for the human ear to distinguish the recording from analog.

It seems to be the Holy Grail of audio,only you can say if it adds something to your listening.

If my notebook had a SPDIF output capped at 24/96 and I had recordings that I wanted to play at 24/192,then it's time to plug in the USB.

 

[joe_cool]

All this discussion and confusion about Firewire, USB, SPDIF, I2S and DACs seems to revolve around the fact that at some point the signal enters the realtime-domain and this is where jitter becomes a problem. PLLs in DACs (SPDIF and USB receivers, actually) cannot completely resolve this issue, not objectively and not subjectively.

 

[ninjikiran]

Depends on your driver implementation, the spdif out on my sound card can send a file out in its native sample rate be it 44.1, 48, and 96. Meaning I can use WASAPI and the operating system doesn't touch it at all(nor do I have to resample or anything like that).

If you have a good USB driver for it than I would just use the USB. Regardless most sound cards suck(including on board) and force a resample to its "master" rate so your better off just using USB in most situations.

I don't believe in magic hoodoo voodoo either so only difference between USB/Spdif/Toslink far as audio is concerned is their connection. Obviously distance doesn't factor into this equation since most people don't have long distance setups.

 

[bearbb]

If you want to use usb, you could try some usb cable like Wireworld Ultraviolet USB. It sounds better with those normal usb cables.

If you want to use spdif, you could try musiland 01 usd or hiface. musiland 01 is cheaper than hiface, and I think hiface got a better sound quality.

I own all of them, I will rank them as follow:

hiface --> Wireworld Ultraviolet USB --> musiland 01 usd