With a CD/DVD drive, is there any reason NOT to use S/PDIF output?

[Ken90630]

Hey, All,

Quick question: As the title implies, is there any reason NOT to use S/PDIF out from my PC's CD/DVD-RW drive? My motherboard has an S/PDIF input, so would there be any reason NOT to keep the signal chain from CD/DVD drive-to-motherboard in the digital domain? What would be a reason to use analog out from the CD/DVD drive instead?

 

[Cerb]

If you want a good signal chain, get a good CD ripping drive (any with a Mediatek chipset will do, like most Samsungs), good CD ripping software (EAC is the best free one, still), and make lossless rips. Then, play those files back. SATA is quite digital .

Your motherboard audio's SPDIF output is a totally different thing, and I don't think a an optical drive has been made for 10 years, maybe 15, that plays CDs worth a damn. Most will skip on any imperfectly-balanced CDs, and all will do poor interpolation if missed sets of samples. Except for a few Plextors, good CD playback ended with the coming of cheap DVD burners (where cheap was <$100, back in the day).

Using the audio out from your ODD is just going to get you any interference inside the case that can make its way into an audible tone, or rectify to an audible tone in an opamp along the way. On top of that, the analog section will not have been implemented well by the maker of the drive, and maybe not by the maker of the chip it's coming off of, either.

Treat CDs as backup storage devices for your music, and get with the times. HDDs and RAM are cheap.

 

[Ken90630]

Thanks, Cerb. Good info.

What if my CD/DVD drive is PATA rather than serial? (It is a 3-year-old Asus, and it's PATA.) I can't believe I don't know the answer to this next question, but do PATA cables carry digital audio signals or just data?

I don't use my PC's CD/DVD drive to listen to music very often. Just occasionally. But I do use it to, as you mentioned, rip lossless CDs (which I typically save as .WAV files). My main purpose for doing this is to make CDs for the car and also to make backups of important CDs in case they get scratched. So I really just need the best signal path for that. That being the case, are the analog cables and S/PDIF output cables (from the optical drive) irrelevant then? I was thinking that I need an audio cable coming off the optical drive and going to the motherboard, but maybe I'm completely wrong about that. I can't believe that after all these years I don't know the answer to that.

If I am wrong about that, then basically the audio-out cables from the CD/DVD drive (whether analog or S/PDIF) will only be used to listen to CDs thru a computer's motherboard or sound card (to speakers) and won't come into play when ripping CDs. Would that be correct?

 

[DaveSimmons]

Yes, the audio cable is not used when ripping with modern software, the software uses the SATA / PATA cable. Even most CD playback done without ripping will probably just use the data cable. I haven't connected an audio cable to my motherboard in many years.

Good ripping software like EAC and dbPowerAmpt that uses AccurateRip grabs the digital data off of the disc, losslessly. If you pick a lossless format like FLAC or Apple's lossless to store it on your hard drive it's the exact digital bits from the CD.

This ripping treats the CD as data, not as audio. It doesn't matter whether the drive is SATA or PATA, both are used to read the data from the disc as data.

 

[Cerb]

A data CD is very different from a music CD, but when you rip the CD, and usually when playing it, you're getting data over the ATA interface. The drive matters to some degree, because the CD was designed with imperfections in mind, and to keep playing unless they were really bad, by trying to fill in missing parts, and then just skip the really bad parts, when that couldn't be done. Since nothing new gets designed for that or tested for that (as opposed to say, a new BD player), they're usually not good at it. While I'm not sure about WMP, iTunes, for example, does a good bit of software error correction, and is actually a decent CD ripper.

For ripping, you can buy the Asus DRW-24B1ST, or Samsung SH-224DB, and be reasonably assured that the drive will handle all but the worst CDs, and accurately report errors, at least those that it cannot correct (if bad data is given, but not reported, you'll see it, but the ripping program will have a hard time figuring out where it needs to re-read, interpolate, or whatever else it will do). Your current drive might be a good one, for that matter, though.

If you are playing the CD from most CD playback software, the audio is being read over the ATA cable. There is probably some way to use the other outputs, but I don't know it (or, maybe it "just happens" when playing a CD...I don't think I've had that connector hooked up to anything since I had an ISA bus Sound Blaster!). Old drives would often just play a CD, if you stuck it in, and some had a play button, but that was back in the 90s.

Some useful links I was able to Google up:
http://www.dbpoweramp.com/spoons-audio-guide-cd-ripping.htm
http://www.dbpoweramp.com/cd-ripper-setup-guide.htm
http://blowfish.be/eac/
dBPowerAmp is EAC's only competition, for good ripping, on Windows.

With FLAC, you can typically fit 2500-3000 CDs in 1 TB, so storage of a lossless CD archive (never needing to go to the discs again), including backups, is pretty cheap. If I needed to make a CD for my car, I would just use Foobar2000's CD burner add-on, and do it right from my playlist .

 

[piasabird]

Digital sigals are data. Otherwise they would not be digital. It is the sound device that makes the sound. So how about HDMI out? they just put the digital signal along with the Video. If you import this into say a HDTV, the HDTV is creating the sound from the digital 5.1 or 7.1 digital stream. This is how I understand it.

My understanding is that dolby digital or SPDIF is Compressed.

This is what Turtle beach said about SPDIF:
USING THE OPTICAL S/PDIF DIGITAL OUT:
All of the AA products come with a built-in Optical S/PDIF Digital Out.
When used with our customized driver software, all of the AA products'
digital outputs can act as a Dolby Digital "Pass-Thru," meaning that you
can use them to pass the Dolby Digital-encoded audio data from the DVD
soundtrack to an external Dolby Digital decoder (usually a Dolby Digital
Receiver). The decoder separates the audio into separate channels, which
are sent to the receiver's amplifiers, and then to the speakers in your
home theater.

The signal is pass through for dolby digital DATA. I think HDMI has the same thing. My research says HDMI version 1.4 has loss less digital audio capabilities.

http://en.wikipedia.org/wiki/HDMI
"Note that it says Dolby Digital is Compressed!"
This is what the Wiki says about HDMI Audio:
For digital audio, if an HDMI device supports audio, it is required to support the baseline format: stereo (uncompressed) PCM. Other formats are optional, with HDMI allowing up to 8 channels of uncompressed audio at sample sizes of 16-bit, 20-bit and 24-bit, with sample rates of 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz and 192 kHz.[20][55] HDMI also supports any IEC 61937-compliant compressed audio stream, such as Dolby Digital and DTS, and up to 8 channels of one-bit DSD audio (used on Super Audio CDs) at rates up to four times that of Super Audio CD.[55] With version 1.3, HDMI supports lossless compressed audio streams Dolby TrueHD and DTS-HD Master Audio.[55] As with the YCbCr video, device support for audio is optional. Audio Return Channel (ARC) is a feature introduced in the HDMI 1.4 standard.[56] "Return" refers to the case where the audio comes from the TV and can be sent "upstream" to the AV receiver using the HDMI cable connected to the AV receiver.[56] An example given on the HDMI website is that a TV that directly receives a terrestrial/satellite broadcast, or has a video source built in, sends the audio "upstream" to the AV receiver.[56]

The HDMI standard was not designed to pass closed caption data (for example, subtitles) to the television for decoding.[57] As such, any closed caption stream must be decoded and included as an image in the video stream(s) prior to transmission over an HDMI cable to be viewed on the DTV. This limits the caption style (even for digital captions) to only that decoded at the source prior to HDMI transmission. This also prevents closed captions when transmission over HDMI is required for upconversion. For example, a DVD player that sends an upscaled 720p/1080i format via HDMI to an HDTV has no way to pass Closed Captioning data so that the HDTV can decode it, as there is no line 21 VBI in that format.

 

[Cerb]

My understanding is that dolby digital or SPDIF is Compressed.

Stereo isn't. Surround is--it's lossy encoded into a stream that would otherwise carry uncompressed stereo audio. However, SPDIF was never a good transport system, if you were after accuracy. It just happened to be what everyone ended up already having, much like how RCA connectors for the analog side of things came about.

Also, I knew HDMI was originally half-baked, but no direct CC support? Man, that's myopic!

 

[mfenn]

Hey, All,

Quick question: As the title implies, is there any reason NOT to use S/PDIF out from my PC's CD/DVD-RW drive? My motherboard has an S/PDIF input, so would there be any reason NOT to keep the signal chain from CD/DVD drive-to-motherboard in the digital domain? What would be a reason to use analog out from the CD/DVD drive instead?

To actually use the S/PDIF output, you must play the disk via the controls on the front panel of the drive itself, and have your mixer controls set up to send the S/PDIF input out your speakers. If you play the CD from any sort of software player, you are reading the disk through the normal data connection.

So there is one very good reason NOT to use your drive's S/PDIF output, it's a pain in the butt.