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Quote:
Originally Posted by E-Stat
When you rip to hard disk (I also use EAC), you must specify the coding (WAV, MP3, etc.) that the software uses to encode the bitstream coming off the CD.
But it never gets converted into a PCM signal. That's where the timing/clocking/jitter problem comes in - when the PCM signal is transmitted to another device like the DAC.
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Quote:
Originally Posted by Feanor
That is, as read by the computer DVD/CD drive? I would say not very. I was playing with Exact Copy a couple of weeks ago and ran through a dozen of so CDs. In fact, the highest number of errors any any of the discs I tried was 3 and several had zero errors, (as detected by Exact Copy). Exact Copy corrected them 100%, so it claimed.
That is, with the exception of the CDR that purposely scratched deeply in several places as an experiment. Exact Copy persevered and was able to copy virtually all of the discs but indicated that it could not guarantee that the correction was 100%. The process to 1.5 hours!!
What type of disc are you using? CD+RW, CD-RW etc.
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Quote:
Originally Posted by E-Stat
While there is not yet consensus on the issue, I understand the challenge to be one of timing. The exact timing may not be returned.
There is no timing problem at that point, when you're just ripping the CD to a WAV or whatever.
Can't somebody back me up on this? I'm not an EE, but everything I've read -- if I understand it correctly -- says timing/jitter is only an issue downstream, where clocking needs to be done.
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Quote:
Originally Posted by Feanor
That is, as read by the computer DVD/CD drive? I would say not very. I was playing with Exact Copy a couple of weeks ago and ran through a dozen of so CDs. In fact, the highest number of errors any any of the discs I tried was 3 and several had zero errors, (as detected by Exact Copy). Exact Copy corrected them 100%, so it claimed.
That is, with the exception of the CDR that purposely scratched deeply in several places as an experiment. Exact Copy persevered and was able to copy virtually all of the discs but indicated that it could not guarantee that the correction was 100%. The process to 1.5 hours!!
Are you sure you're interpreting the output properly?
I'm talking about getting error-free rips AFTER error correction.
When EAC gives the you Track Quality "98% accurate" or whatever, it's reporting the accuracy of the rip BEFORE error correction. Once the errors are corrected, it's usually 100% error-free.
If you get errors EAC cannot correct, it will say something like "suspicious position at X:XX" or somesuch.
See the FAQ here:
http://www.exactaudiocopy.de/
Quote:
Q: What does the Track Quality really mean? A few times I get 99.7% or 97.5%. But there are no suspicious position reported.
A: When you get 99.7% and so on, that means that a bad sector was found, but the secure mode has corrected it - from 16 times of grabbing the sector, there were 8 or more identical results. So it only indicates read problems. It is the ratio between the number of minimum reads needed to perform the extraction and the number of reads that were actually performed. 100% will only occur when the CD was extracted without any rereads on errors. ONLY when there are suspicious positions reported, there are really uncorrectable read errors in the resulting audio file.
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That's my take too. Timing is an issue when the bits hit the DAC. And, it shouldn't be an issue there because now DACs have buffers and re-clock (internal or external). The bits SHOULD flow at a precise PCM rate. But, they may slow or speed up if the sending clock is not so great (which it might not be) but a good DAC will correct that provided the buffer is not exceeded. Timing may also be misinterpreted if there are interferring signals (like reflections at the ends of cables or some God awful electromagnetic power burst) that can cancel or extend some peaks, but again the DAC should compensate and IF there are such distortions in the transmission you've probably got bigger problems living near a power station or something.
I can't see how timing would effect ripping with error correction in play. I could see how the outgoing PCM signal from the PC might not be perfectly clocked.
I'm not really backing you up with references, but I would like to know at specifically what stage this supposed jitter is being introduced?
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Quote:
Originally Posted by noddin0ff
And, it shouldn't be an issue there because now DACs have buffers and re-clock (internal or external).
I've read a great deal of debate about whether DACs can deal with jitter sufficiently. Benchmark says their DAC can do it, but a lot of people dispute that as marketing. I don't know for sure what the answer is on that, but to me, anyway, it's inaudible.
Quote:
Originally Posted by noddin0ff
I'm not really backing you up with references, but I would like to know at specifically what stage this supposed jitter is being introduced?
My understanding is that jitter gets introduced once the PCM signal is transmitted to another device, like a DAC. There's a lot of technical discussion about it in that thread I've posted to a couple times now.
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Good question!
Quote:
Originally Posted by bonsaiguitar
What type of disc are you using? CD+RW, CD-RW etc.
It is a DVD?RW drive, but since I've never tried to record anything on this particular drive, I don't know whether it's DVD-RW or DVD+RW or both. :confused5:
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Pretty sure but ...
Quote:
Originally Posted by Mike Anderson
Are you sure you're interpreting the output properly?
I'm talking about getting error-free rips AFTER error correction.
When EAC gives the you Track Quality "98% accurate" or whatever, it's reporting the accuracy of the rip BEFORE error correction. Once the errors are corrected, it's usually 100% error-free.
If you get errors EAC cannot correct, it will say something like "suspicious position at X:XX" or somesuch.
See the FAQ here:
http://www.exactaudiocopy.de/
Frankly I don't recall the details. Yes, from normal errors recovery is typically 100% with message a long the lines you indicate.
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When transferring data from a computer to a DAC, timing is a problem *before* the data reaches the DAC! Computer hard drives do not read data in quite the same way as a CD player. The computer reads the data in variable-sized "bursts" which are copied in fixed sized "blocks" to a memory "buffer." The data is then sent in a stream to the output port. When transferring this data through a USB port, the DAC has *no* control over the rate the computer sends the data. To ensure that the DAC's local buffer doesn't overflow nor underflow, the DAC must use a local clock that can adjust itself over a relatively large range so that its word-clock frequency equals the average of the incoming data. Such a local clock will not be super precise. Also, if you send the data wirelessly, you run into essentially the same problem because the DAC does not control the data source.
The following reference contains some more details about USB transmission and jitter.
http://www.audioasylum.com/forums/pc...ages/7719.html
The following is an excellent summary of eight distinct contributors to jitter.
http://www.positive-feedback.com/Issue22/nugent.htm
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Thanks, GC
Quote:
Originally Posted by GCRhoads
When transferring data from a computer to a DAC, timing is a problem *before* the data reaches the DAC! Computer hard drives do not read data in quite the same way as a CD player. The computer reads the data in variable-sized "bursts" which are copied in fixed sized "blocks" to a memory "buffer." The data is then sent in a stream to the output port. When transferring this data through a USB port, the DAC has *no* control over the rate the computer sends the data. To ensure that the DAC's local buffer doesn't overflow nor underflow, the DAC must use a local clock that can adjust itself over a relatively large range so that its word-clock frequency equals the average of the incoming data. Such a local clock will not be super precise. Also, if you send the data wirelessly, you run into essentially the same problem because the DAC does not control the data source.
The following reference contains some more details about USB transmission and jitter.
http://www.audioasylum.com/forums/pc...ages/7719.html
The following is an excellent summary of eight distinct contributors to jitter.
http://www.positive-feedback.com/Issue22/nugent.htm
Very interesting indeed.
My bottom line is that configuration using the M-Audio Audiophile USB sounds practically no worst -- nor better -- than my CDP.
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Quote:
Originally Posted by GCRhoads
Also, if you send the data wirelessly, you run into essentially the same problem because the DAC does not control the data source.
The wireless setup I'm talking about sends a network signal, not a PCM stream. It doesn't require clocking at that point; it's no different than getting a wireless signal on your laptop, only here the receiving device is the Squeezebox.
The SB then outputs a PCM signal/SPDIF stream via the usual hard-wired outputs to an external DAC (or the SB's internal DAC, if you want to use that). That's where the potential for jitter arises.
But really, it's inaudible at that point, particularly if you use a decent external DAC.
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Quote:
Originally Posted by Mike Anderson
The wireless setup I'm talking about sends a network signal, not a PCM stream. It doesn't require clocking at that point; it's no different than getting a wireless signal on your laptop, only here the receiving device is the Squeezebox.
The SB then outputs a PCM signal/SPDIF stream via the usual hard-wired outputs to an external DAC (or the SB's internal DAC, if you want to use that). That's where the potential for jitter arises.
But really, it's inaudible at that point, particularly if you use a decent external DAC.
I did some research into the Squeezebox, and it looks like a very cool device. The only drawback that I saw was the lack of an on-screen display for organizing playlists and simply finding the music I'd want to play. The device has a large display, but my system is tucked into an audio rack with a perforated metal screen door. Remote sensors work fine, but I can't really read any of the device displays.
Of course, once you add the OSD, then others will demand video streaming, slide shows, etc. and it will be no different than any other media server.
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Quote:
Originally Posted by Woochifer
I did some research into the Squeezebox, and it looks like a very cool device. The only drawback that I saw was the lack of an on-screen display for organizing playlists and simply finding the music I'd want to play. The device has a large display, but my system is tucked into an audio rack with a perforated metal screen door. Remote sensors work fine, but I can't really read any of the device displays.
Of course, once you add the OSD, then others will demand video streaming, slide shows, etc. and it will be no different than any other media server.
By on-screen I take it you mean on your TV screen? You can control it from a laptop, and there may well be a way to put it on your TV as well.
You'd be welcomed to come check out my setup if you like. I'm in Emeryville.
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Many of us still enjoy the process of selecting a CD and placing it in a machine.There is an enjoyable ritual in this and we also have the chance to read about the recording ,musicians and lyrics.Of course this is even more profound with records.
To me this shows due respect to the music and to the performers.
Even the move away from hard plastic cases to more book like paper ones helps us make this connection.
JT
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binary differences in ripped files
Sorry to wake up an old thread, but I thoroughly enjoyed reading through this. I have a Squeezebox on order so this thread really cought my interest and I thought I might be able to add something to the debate somewhere.
So, I decided to tackle the question of whether all "1s and 0s" were created equal. I think this can be dug into from a lot of different directions, but I chose a very simple one. The first question in my mind is: do 2 rips of the same source material end up bit-for-bit identical? That one was easy. I used Exact Audio Copy to create the 2 rips on my WinXP laptop, then I compared them (bit-for-bit) with "diff" on my linux box. Result: these files are identical, wheh ... the hurdle has been leapt.
Then I did a rip on my linux box using "cdparanoia" and diff'd it with the exact audio rip. Although the files all appeared to be the same size, "diff" claimed the binary files to be different. To dig into the details I told "diff" to pretend they are text files and show me the differences. Well, the biggest differences were in the first and last line, presumably some sort of formatting differences due to the different programs that we can ignore for this discussion. There were also a smattering of differences within the body of the file. So it appeared that not all "1s" and "0s" were created equal. However, the percentage of the file content that differed was only 0.0003% or 1 bit in roughly 3 million.
This is when I noticed that 'cdparanoia' puts out some info on errors as it goes, and I realized there were some on that first track. Well, I chose a track that had no errors reported from 'cdparanoia' and diff'd it with its exact audio twin and that is eactly what it was. Save the first and last line they were bit for bit the same.
I don't think this necessarily says all 1's and 0's were created equal, but it provides evidence that computers reproducably rip CDs even between programs, OSs and machines. In that sence, it seems computers are extracting exactly the data sets that are on CDs. Maybe this isn't the case for older CDs (I'm testing an older one now) but it appears so for new CDs.
Maybe the reason why there is an audible improvement with very, very high end stand alone CDPs is that these machines don't exactly extract the CD data, instead they do some signal processing that improves it, like how a "unsharp mask" can make a photo look better.
anyway, cool topic.
cheers,
mark
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I got the same test results from a fairly old CD. It's a Cat Stevens clasics CD purchased in the early 90's. On the cd it says 1987. Is this old enough? When I stick it in a windows machine and file browse to it, I do see the individual tracks.
-m
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Using PC as music server to home stereo
Quote:
Originally Posted by Mike Anderson
I don't use a dedicated PC, I just used what I already had sitting around, which is the same computer we use to do everything else. It simply doesn't require that much memory to run the music server software.
I don't use the sound card either, all the encoding and conversion is done offboard.
I did get an external hard drive, but those aren't that expensive these days, and it isn't necessary unless your present hard drive isn't large enough to accomodate your collection.
Note: I have nearly 8,000 "songs" (many of which are really radio show segments running up to an hour), and 99% of it is in FLAC (lossless compression, about half the size of redbook CD file sizes). It's still not a problem for my PC.
As I am considering using an external USB soundcard/DAC to play WAV music files (96 sampling 24 bit) via home stereo (NAD amplifier and B&W speakers), will I get same sound fidelity compared to playing DVD-audio or CD discs via NAD cd/dvd player.
Thanks
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Quote:
Originally Posted by gbowers
As I am considering using an external USB soundcard/DAC to play WAV music files (96 sampling 24 bit) via home stereo (NAD amplifier and B&W speakers), will I get same sound fidelity compared to playing DVD-audio or CD discs via NAD cd/dvd player.
Thanks
Based on my own experience using a NAD CD Player and a Mac Mini, I would say yes...
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If any sound quality is lost I sure can't tell with my ears.
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External USB sound card or DAC
Quote:
Originally Posted by Ajani
Based on my own experience using a NAD CD Player and a Mac Mini, I would say yes...
What external USB sound card or DAC (M-Audio Audiophile USB) are you using to move bit stream from PC to home stereo.
Bonsaiguitar, please update.
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Quote:
Originally Posted by bonsaiguitar
If any sound quality is lost I sure can't tell with my ears.
What external USB sound card or DAC (M-Audio Audiophile USB) are you using to move bit stream from PC to home stereo.
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Quote:
Originally Posted by Ajani
Based on my own experience using a NAD CD Player and a Mac Mini, I would say yes...
What external USB sound card or DAC (M-Audio Audiophile USB) are you using to move bit stream from PC to home stereo.
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Quote:
Originally Posted by gbowers
What external USB sound card or DAC (M-Audio Audiophile USB) are you using to move bit stream from PC to home stereo.
Bonsaiguitar, please update.
For the Mac Mini, I didn't use either, just the standard Mac soundcard (which was suprisingly good).... But if you don't find that your computer soundcard is up to the task, then you have a number of good USB DACs available (depending on your budget)...
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Quote:
Originally Posted by Ajani
For the Mac Mini, I didn't use either, just the standard Mac soundcard (which was suprisingly good).... But if you don't find that your computer soundcard is up to the task, then you have a number of good USB DACs available (depending on your budget)...
The fubar dac looks pretty good, for a 100$ its worth a shot.
I use an old creative usb external soundcard, it sounds very good, but I think I will go the DAC route.
And yes, the high end CD player is dead, if you want one go ahead, but when you realize that computer audio is just as good , if not better, well, that will be a sad day
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