[StanleyB1]

Quote:

Originally Posted by bordins /img/forum/go_quote.gif A decent external USB sound device such as M-Audio or EMU offers low jitter S/PDIF transmission, given you have a good digital cable.

Oh no, not that old wife's tale again. Jitter is the bogey man of digital audio. It's just another marketing tool. Anyone ever seen a chart of digital reproducers that compares their jitter perfromance? Maybe a review article in one of the audio magazines?

 

[mrwinick]

This last week I was having some problems with my computer setup (imac-vlc media player-optical cable-OMZ-rca-mpx3-cardas-hd600) so I temporarily hooked up a philips 963sa instead. When I got my computer issues resolved I hooked it back up too, but both my dac and amp have two inputs, so I hooked everything up and was able to switch back and forth. I listened to some of my favorite music (clapton unplugged and miles davis kind of blue) and it seemed as if there was a noticeable difference. I say seemed to be because I know how that goes....... Regardless, listening thru the philips the music seemed louder (? which might be creating any number of effects..) but also more transparent and more immediate. The bottom line is that I would describe it as better. So, first I'd like a simple 'show of hands' of who thinks I'm nuts and who thinks there might actually be a difference. Second, for those who don't think I'm nuts (if any) is there anything I can do to get my computer to reproduce the music closer to what I get from the cd player? Thank you.

 

[randyruiz]

Quote:

Originally Posted by StanleyB1 /img/forum/go_quote.gif Every time I read any such statement on the net I cringe. CD audio is riddled with errors on the discs. If it wasn't for Solomon-Reed we would have a serious problem. So imagine ripping a CD that has been 'error corrected' by the hardware. Is the rip a true copy of the original data, or a reflection of the eroor corrected data? But wait, there is more! Not all audio data on a CD is what you imagine it to be. Put for instance a Nora Jones's CD in your PC and then go to File Manager (or Directory Opus in my case). Is that a .dll that I see??? Surely my CD player cannot read driver software? So what is my PC ripping exactly? Individual bits directly off the disc, or information stored in a database of some sort? And what is a video file doing on my Katie Melua CD? My CDP doesn't play it, but my PC does. So is my CD player bit accurate, or my PC 'seeing' data that my CDP can't see? So this whole bit accurate ripping yarn doesn't quite add up. If what I can play on a CDP off a disc is different in content to what I can play off the same disc on a PC, there is an obvious method in existance to prevent us from ripping a disc bit accurate.

Stanley,
I don't mean this to be insulting or belligerent in any way, however you have no Idea what you are talking about. I apologize in advance on how my response sounds.

 

[nick_charles]

Quote:

Originally Posted by StanleyB1 /img/forum/go_quote.gif I spent endless hours trying to make mp3 sound impressive and almost as good as 16 bit audio when played via my DAC? You think many cared? Nope. The iPOD generation is not into bit accuracy. Never mind about buying a bit accurate headphone...

I am beginning to think we worry too much about bit-accuracy for practical day to day audio purposes. I have spent several amusing hours this weekend doing some D to D recordings.

I ripped a CD track (5 mins 37 seconds) into wav format. Then I connected up two different USB soundcards (Behringer UCA202 set to 16/44.1 and DS, and Edirol UA-1EX) to my laptop, connected them together d-out to d-in with the cheapest optical cable I own.

Then I played the track back in Cool Edit pro from one card (Behringer) and recorded it on the other (Edirol) using Audacity. Then I trimmed the new track down to the same size (exactly the same size in samples). I loaded up the tracks in Cool Edit pro did a 65K FFT analysis of the spectra for the tracks and loaded the results into a spreadsheet.

Interestingly the Left channels were identical, this puzzled me so much that I repeated the experiment, same result , left channels on original and recording were identical , but there were minor deviations between the right channels, puzzling but there you go.

ave.......-0.00008712 db
min.......-0.11727905 db
max......0.05999756 db

Maybe a difference of .1db would be just noticeable , however on the original track the intensity of this specific frequency was - 144db and in any case this is an acculmulated 0.1db difference over the length of a 5:37 track.

In terms of db variations between original and copy there were few notable instances.

>0.1......1
>0.05.....3
>0.01.....158
>0.005...608

Visibly the waveforms were identical in shape and intensity zoomed down almost to sample level

needless to say I did an ABX on these, the result was 50% viz guessing.

So using possibly the worst setup imaginable USB....Optical.......Optical......USB two different pieces of playback/record software , two cheap USB devices and a bog-standard optical cable I got a recording that was audibly utterly indistinguishable from the original.

so why worry ?

 

[joe_cool]

I have to agree with Nick. I often use EAC and find some comfort in bit-perfection, but I can't hear the difference between Foobar, EAC and Nero when it comes to CD extraction.

 

[Uncle Erik]

Quote:

Originally Posted by mrwinick /img/forum/go_quote.gif This last week I was having some problems with my computer setup (imac-vlc media player-optical cable-OMZ-rca-mpx3-cardas-hd600) so I temporarily hooked up a philips 963sa instead. When I got my computer issues resolved I hooked it back up too, but both my dac and amp have two inputs, so I hooked everything up and was able to switch back and forth. I listened to some of my favorite music (clapton unplugged and miles davis kind of blue) and it seemed as if there was a noticeable difference. I say seemed to be because I know how that goes....... Regardless, listening thru the philips the music seemed louder (? which might be creating any number of effects..) but also more transparent and more immediate. The bottom line is that I would describe it as better. So, first I'd like a simple 'show of hands' of who thinks I'm nuts and who thinks there might actually be a difference. Second, for those who don't think I'm nuts (if any) is there anything I can do to get my computer to reproduce the music closer to what I get from the cd player? Thank you.

The reason it seemed louder is probably because it was louder. Sources have a variety of output voltages and impedances. More voltage means a louder sound. Impedance also plays a part because the preamp circuit has an input impedance.

The closer the two impedances match, the better the power transfer is. So if you have two sources, the one with the better impedance match will transfer more power.

Odds are that the CD player puts out more power than your computer does. That means the amp amplifies it more than the other signal, even though the volume knob is at the same place.

If the two sources were volume matched you might have a harder time telling them apart.

 

[Fidelity]

EAC + AccurateRip plug-in verification (via online database) is the only way to be absolutely sure you have 100% bit perfect CD rips.

 

[mrwinick]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif The reason it seemed louder is probably because it was louder. Sources have a variety of output voltages and impedances. More voltage means a louder sound. Impedance also plays a part because the preamp circuit has an input impedance. The closer the two impedances match, the better the power transfer is. So if you have two sources, the one with the better impedance match will transfer more power. Odds are that the CD player puts out more power than your computer does. That means the amp amplifies it more than the other signal, even though the volume knob is at the same place. If the two sources were volume matched you might have a harder time telling them apart.

THAT makes sense. Thank you. It's also good news. I was worried I'd have to switch back to the hassle of changing cd's all day. (I have compared the sources again, but this time I adjusted the volume to try to make it more equal and sure enough if there is a difference in quality I can't hear it.)

 

[japc]

Quote:

Originally Posted by StanleyB1 /img/forum/go_quote.gif So this whole bit accurate ripping yarn doesn't quite add up. If what I can play on a CDP off a disc is different in content to what I can play off the same disc on a PC, there is an obvious method in existance to prevent us from ripping a disc bit accurate.

Ah... What !? Are you kidding ?

Oh, and no, CD audio is not "riddled with errors on the discs". There's jitter and maybe some errors but is far from riddled.

 

[BigTony]

I'm not sure if the op question has been answered!
The difference bettween 'ripping to losslesd' vd cdp is that the rip isn't in realtime so any disc re-reading etc and error correction can be carried out. A cdp doesn't have the time, and so error corrects on the fly, or skips. Both approaches have flaws, but were kinda arguing over tiny fractions of a percent. I use lossless rips so i can be lazy and use a music server, but my cpd is 'better' audio wise than my sb3/dac combo (but then my cdp was 3x the price).

 

[StanleyB1]

Quote:

Originally Posted by japc /img/forum/go_quote.gif Ah... What !? Are you kidding ?

Nope. I have been working in that industry on and off since 1982. That includes R&D for both Sony and Philips. So there is a background to my statements that doesn't rely on data gleamed from the internet.

 

[XXII]

Quote:

Originally Posted by StanleyB1 /img/forum/go_quote.gif Every time I read any such statement on the net I cringe. CD audio is riddled with errors on the discs. If it wasn't for Solomon-Reed we would have a serious problem. So imagine ripping a CD that has been 'error corrected' by the hardware. Is the rip a true copy of the original data, or a reflection of the eroor corrected data?

I don't understand what you're saying. I can agree with the fact the burning process introduces errors in to the data but when reading the disc, these errors should be corrected by Solomon-Reed. The idea is that after applying Solomon-Reed, the data you read from the disc should be more or less identical to the original data so it doesn't matter that the data on the disc is riddled with errors.

 

[StanleyB1]

Quote:

Originally Posted by XXII /img/forum/go_quote.gif I don't understand what you're saying. I can agree with the fact the burning process introduces errors in to the data but when reading the disc, these errors should be corrected by Solomon-Reed. The idea is that after applying Solomon-Reed, the data you read from the disc should be more or less identical to the original data so it doesn't matter that the data on the disc is riddled with errors.

Applying Solomon-Reed is not designed to recover the data once the error level has passed a certain point. It is then used to construct a digital bit stream that will sound acceptable to the ears once converted into an analogue one.

 

[XXII]

Quote:

Originally Posted by StanleyB1 /img/forum/go_quote.gif Applying Solomon-Reed is not designed to recover the data once the error level has passed a certain point.

I agree that Solomon-Reed (like all error correcting codes) can only correct so many errors. So you are saying that the burning process introduces so many errors that Solomon-Reed cannot correct them all? I would be interested in how you know this.

Quote:

Originally Posted by StanleyB1 /img/forum/go_quote.gif It is then used to construct a digital bit stream that will sound acceptable to the ears once converted into an analogue one.

So you are saying that Solomon-Reed has the additional property of guessing the correct values of the digital signal beyond its error correcting threshold? I didn't know this.

 

[AudioPhewl]

Quote:

Originally Posted by japc /img/forum/go_quote.gif Ah... What !? Are you kidding ? Oh, and no, CD audio is not "riddled with errors on the discs". There's jitter and maybe some errors but is far from riddled.

Okay, I agree with you that Stanley had it wrong about the ripping aspect(audio extraction is audio extraction, the rest of the disc is irrelevant beyond this). I don't think his understanding is wrong, but what he actually wrote is.

But every CD _IS_ riddled with errors. Physical ones - literally, pinholes on the discs. It's been a well-documented fact since before I first started messing with audio, back in 1993.

~Phewl.