Is All SPDIF Audio Output the Same? 97
CyberSpaZtiK asks: "I am going to build a Linux audio appliance to hold my music collection in various formats and for output to my stereo system. Because of a probable lack of Linux availability or support for audio cards with high quality D/A converters and low-noise electronics (or am I mistaken?), I want to keep the output path completelely digital by using a card with SPDIF output. However, it occurs to me that I actually know very little about SPDIF - are all SPDIF outputs made equal? Can I expect every SPDIF interface to emit the exact PCM data of the source audio, or are there over/under-sampling/aliasing, etc. issues that you sometimes get with digital signal processing? What do I need to understand about SPDIF and/or other digital output interfaces to make an informed decision?"
Use TOSLINK instead (Score:5, Informative)
Some cards, however, such as Creative's Audigy series, are notorious for resampling inputs/outputs, so you might want to check.
Even a cheap card, like the $15 cards on Newegg, should provide a clean output. Don't buy the garbage about "jitter" that I'm sure someone will bring up - so long as your card and cabling are operating within the specification, you won't have any problems.
Do consider TOSLINK instead, however. TOSLINK uses fiber-optics, so your audio equipment and PC are electrically isolated. This reduces the chance of creating a ground loop or introducing RF noise into your reciever/amp. Moreover, it protects your equipment in the event of an electrical mishap.
Re:Use TOSLINK instead (Score:2, Informative)
I would just like to confirm what you say about TOSLINK. My PC is currently too far from my receiver for my optical cables to stretch, so I have to use the SPDIF connection. Every time there is an electrical event in my house (heating, fridge, freezer, kettle switching) the audio cuts out for a second or so.
Re:Use TOSLINK instead (Score:1)
This is most likely due to faulty wiring and/or a ground loop [epanorama.net]. The linked page provides a very good description of the problem.. Unfortunately, it's usually quite hard to locate a ground loop, and they
Re:Use TOSLINK instead (Score:4, Informative)
Do consider TOSLINK instead, however. TOSLINK uses fiber-optics, so your audio equipment and PC are electrically isolated. This reduces the chance of creating a ground loop or introducing RF noise into your reciever/amp. Moreover, it protects your equipment in the event of an electrical mishap.
One slight clarification, TOSLINK normally does carry SPDIF. TOSLINK is primarily just detailing the physical medium, the data is still encoded as SPDIF (which can also be carried on wire). The original author didn't specify how he was intending to use SPDIF, it may have been over either medium.
Re:Use TOSLINK instead (Score:2)
One slight clarification, TOSLINK normally does carry SPDIF. TOSLINK is primarily just detailing the physical medium, the data is still encoded as SPDIF (which can also be carried on wire). The original author didn't specify how he was intending to use SPDIF, it may have been over either medium.
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Um, I'm pretty sure S/PDIF is also the name for the physical connector, namely the RCA plug type of digital audio connector. The data is encoded as Dolby Digital, PCM, or whatever.
Of course, I'm no stereo nu
Re:Use TOSLINK instead (Score:1)
Um, I'm pretty sure S/PDIF is also the name for the physical connector, namely the RCA plug type of digital audio connector. The data is encoded as Dolby Digital, PCM, or whatever.
Of course, I'm no stereo nut so I could be wrong.
Yes, you are wrong. S/PDIF is effectively the data format. It can run over TOSLINK or 75 ohm (read: normal coaxial video) cabling.
And of course the ubiquitous wikipedia link [wikipedia.org].
Re:Use TOSLINK instead (Score:2)
i'm sure that what i heared was that S/PDIF was the original coaxial based system and that TOSLINK was a fibre cabling system based on it that worked using the same protocol.
Re:Use TOSLINK instead (Score:1)
The one thing to know, though, is that the PCM data can be sent at any number of frequencies. While most amps can read at 44.1kHz and 48 (and usually lower frequencies as well), not all can. Additionally, some sound cards (particularly the more generic or
Re:Use TOSLINK instead (Score:1)
Take a look. The wires are side-by-side.
-Peter
Re:Use TOSLINK instead (Score:2)
Re:Use TOSLINK instead (Score:1)
Look, I went the Dollarama way once, when I wanted to hook up my Commodore 64 to a LCD monitor via a scan doubler. The picture had horrible dot crawl. The cheap-ass telephone cables with s-video connectors wee the culprit. A 7$ cable with real coax fixed that problem. I'd ahte
Re:Use TOSLINK instead (Score:1)
Weird.
Anyway, they're coaxial. I'm dumb.
-Peter
Re:Use TOSLINK instead (Score:2)
Admittedly, I don't know squat about this, but I'm pretty sure S/PDIF stands for something along the lines of Sony/Philips Digital Interface (my old roomies were audio engineers). It specifies how the signal is transimitted over the wire. The form the connector takes may vary.
Re:Use TOSLINK instead (Score:2)
Ie, mpeg / avi (containers) or divx / mpeg-4 / mp3 (codecs) ?
Re:Use TOSLINK instead (Score:1)
Re:Use TOSLINK instead (Score:2)
I use video leads which are 75 ohm and cheaper than the specialist 'digital ' links they sell to hi-fi suckers, and I reckon it doesn't re-arrange too many of those pesky '0's and '1's.
I think that jitter probably is crap. It is a digital signal. Having a good quality stable clock is probably important, buy if my computer can keep al
Re:Use TOSLINK instead (Score:2)
In any case, I would be more worried about the
Re:Use TOSLINK instead (Score:1)
In any case, most (if not all) equipment with SPDIF inputs reclocks the signal before doing anything (even loopthrough is reclocked). Again, so long as no link is reporting errors, you're A-OK, no matter what the level of jitter is.
Re:Use TOSLINK instead (Score:1)
Re:Use TOSLINK instead (Score:2, Insightful)
Jitter is an issue for equipment designers; it is not an issue for equipment users. With the aid of a decent lab, you can ver
Re:Use TOSLINK instead (Score:2)
Re:Use TOSLINK instead (Score:1)
Re:Use TOSLINK instead (Score:1)
Re:Use TOSLINK instead (Score:2)
Re:Use TOSLINK instead (Score:1, Interesting)
Re:Use TOSLINK instead (Score:1, Informative)
Most games use DirectSound3D or OpenAL these days, so you shouldn't even notice if you don't have the Audigy, since they do it in software mode that's quite indistinguishable from the hardware -- audio's simply less demandin
Re:Use TOSLINK instead (Score:2)
A card like the M-Audio Audiophile 2496 would be a respectable choice for under $100. I don't have my card handy to look at, but I think it uses a proper transformer for isolation. I don't think the creative labs cards do though. There may
Re:Answer (Score:4, Insightful)
Then why do they have an "Ask Slashdot" section?
Re:Answer (Score:2)
Yes.
Slashdot: News for nerds, stuff that matters.
That second part encompasses any discussion relevant to "mattering." This includes functioning as a support number.
Re:Answer (Score:4, Funny)
"read errors and the like" - Brilliant, thanks. Why don't you post under your member name so I can come kick your ass.
Way to go (Score:1, Troll)
Re:Way to go (Score:1)
What are the Linux jukeboxes missing that
Re:Way to go (Score:1)
Re:Way to go (Score:2, Interesting)
Re:Way to go (Score:1)
Re:Way to go (Score:1)
Re:Way to go (Score:1)
Re:Way to go (Score:1)
Re:Way to go (Score:2)
perl -e "[that post here]"
At least, I think that's how to turn it into English.
Re:Way to go (Score:1)
Features I would like in an audio player that (afaik) are not currently availiable under linux (or at least, are not availiable together to any degree:
Re:Way to go (Score:2)
I am a huge fan of rhythmbox. I prefer it to iTunes any day. I use rhythmbox at home however at work I have to use iTunes (I take my ipod back and forth and plug it in at work). iTunes is alot slower, and has useless eye candy (so many animations ... so useless)
Re:Way to go (Score:1)
Paul.
Just google for jitter. (Score:5, Funny)
Jitter is a bunch of crap (Score:3, Informative)
Any self respecting DAC circuit will not be affected by jitter.
I use toslink all the time and there is no problem with "jitter".
Jitter is marketing hype.
Re:Jitter is a bunch of crap (Score:5, Insightful)
Unless, of course, all your units have synchronized clocks, or each have their own atomic clock.
Unlikely, to say the least.
Jitter is not a problem the average prosumer really needs to worry about, nevermind the average consumer.
The audiophiles who care about it care the same way about their tubes, oxygen-free cables, and green highlighters. Whatever gives you a warm fuzzy feeling, man.
But, technically, it does exist, and it is a problem that results in either doubling up on samples, skipping samples, or some sort of macabre clock synchronization scheme that only ends in tears.
Only, technically, that's not jitter either.
-Adam
Re:Jitter is a bunch of crap (Score:1)
Re:Jitter is a bunch of crap (Score:3, Interesting)
It's not a problem you are ever likely to come across outside a big recording studio where several devices are talking to each other digitally with DAC clocks drifiting compared to each other (oh, and it's easliy solved, the solution is to slave everything to a master clock).
The problem of sending a 44.1kHz signal from one end of your house to another is trivial compared to feeding a broadband signal
Re:Jitter is a bunch of crap (Score:3, Informative)
Re:Jitter is a bunch of crap (Score:1)
I know jitter is real, but it's not really a factor in this instance.
I work for a WISP so I know about jitter in a real environment.
$25 TOSLINK card (Score:5, Informative)
Chaintech's product page [chaintechusa.com]
Re:$25 TOSLINK card (Score:1)
I'm trying to find an inexpensive solution for S/PDIF over TOSLINK for Linux that supports AC3 and DTS, but my messages don't make it to the ALSA list for some reason.
Maybe it's because too many words are all caps!
-Peter
Re:$25 TOSLINK card (Score:2)
In my setup (playing DVDs), the AC3 audio is sent straight to the receiver. The receiver does the Dobly/DTS/THX/whatever decoding. So yes, it works with DTS, since Linux is just shoveling data off the disk and then onto the wire, no matter the encoding.
Here's my /etc/asound.conf where everything goes out the optical out:
There are Consumer and Pro modes (Score:4, Informative)
Re:There are Consumer and Pro modes (Score:2)
The Delta-66 is based upon the same chipset and the website claims SCMS control.
It doesn't have optical S/PDIF, only coaxial, which for me is a royal !#$%. There are converters. A friend of mine has this card and says the analogue ports are very clean and free from a lot of noise.
Re:There are Consumer and Pro modes (Score:2)
IIRC there are 4 settings for copy-protect: prohibit, don't prohibit, and one generation (the other setting is unused). It repeats every frame.
However that's only a minor part of the difference. The big difference between professional and consumer kit is pro kit is ballanced, additionally AES/EBU can support 3 frquencies (44.1, 48 and 96), I believe SPDIFF is limit
MAudio Delta 44 (Score:1, Informative)
Re:MAudio Delta 44 (Score:2)
Most M-Audio cards [m-audio.com] work with Linux ALSA and JACK. If you just want some decent audio output you can buy the Audiophile 24/96 for less than $100 at the store. It has SPDIF out as well.
The Mia card by Echo works as well.
RME has soundcards [rme-audio.com] that work well with Linux too. They will get you some higher quality at a price.
Echo card (Score:2)
It does 20bit 2-in/8-out recording/playback with a very low noise floor, and also offers stereo digital in/out with SP/DIF consumer/pro modes on Linux.
My friend gave me his since Echo no longer do Windows drivers for their old cards.
Re:MAudio Delta 44 (Score:1)
Consider Griffin iMic (Score:2)
In my testing, it's the cleanest sound I've heard from a computer with the exception of optical toslink.
Re:Consider Griffin iMic (Score:2)
One thing to be aware of! (Score:3, Informative)
If anybody know of sound cards available for purchase that actually support this, (the feature is called DICE), let me know.
Re:One thing to be aware of! (Score:1)
Re:One thing to be aware of! (Score:2)
Re:One thing to be aware of! (Score:2)
Re:One thing to be aware of! (Score:1)
Re:One thing to be aware of! (Score:2)
Annoying ain't it? I know more than one person who would love to be able to buy a multichannel soundcard that did realtime AC3 encoding. I believe the now defunct nVidia motherboard was the only way you could do get this type output in a PC and
Re:One thing to be aware of! (Score:2)
Re:One thing to be aware of! (Score:2)
Re:One thing to be aware of! (Score:2)
I wish I could give you more detail but the computer in question is 400 miles away.
Re:One thing to be aware of! (Score:2)
I have tried everything I can think of to get 5.1 AC3 or DTS over regualr RCA coaxial SPDIF, to no avail. Everything I've found leads me to believe it is impossible.
Re:One thing to be aware of! (Score:1)
Re:One thing to be aware of! (Score:2)
Re:One thing to be aware of! (Score:1)
The Creative cards will, however, use CMSS (another Creative invention) to upmix a 2 channel source to 5.1 when used with certain Creative amps. Alternately, there's always Dolby Pro Logic.
Re:One thing to be aware of! (Score:2)
It's not hardware, but: real-time AC3 encoding for JACK [essej.net] might do the trick!
Of course, not so useful for playing games under Windows.
SP/DIF chips (Score:2)
The Phillips UDA1355H [philips.com] looks like what I want, but Phillips doesn't even list availability information, and DigiKey and Mouser say either nothing or non-stock, which leads me to think that the chip doesn't exist.
Does anybody have anything like this?
I already know about PCM2902 USB DAC [hepso.dna.fi] project, and while that's useful (si
SPDIF -- not all are equal (Score:1)
At least according to this site, no. See " 44 KHz Digital Data To Digital Output" sections such as Turtle Beach Santa Cruz [pcavtech.com]. A full list of tested cards is here Here [pcavtech.com]
Good luck, or buy a squeezebox from slimp3 (Score:2)
Mark
No, but Yes if you have the good DAC (Score:2)
Concerning your computer, I don't think it would have any problem in forwarding data at the right rate.
Avoid too much cpu-intensive tasks when listening your music.
People talk about jitter and it's interesting because it mainly affects only the end segment
Benchmark DAC-1 (Score:2)
on spdif jitter (Score:2)
without getting deep in math and tech, the short answer that everyone seemed to agree upon was:
- when sending the signal from a source device to PLAYBACK device, if the target device is a DAC, then jitter does matter.
- when COPYING the data from a device to a storage device (DAT, computer, etc), then jitter does
resampling by internal architecture (Score:2)
sound blasters and their ilk are famous for this.
the envy24 chip is known to be bit-accurate. what you send is what you get. m-audio has these cards.
another good 'musician quality' (bit accurate) card is one that uses the 8738 chip. its cheap and very common.
I think it was M$ (I may