I have posted this at the Adobe forum but it would be difficult for many to follow as you can’t access without login.
So here goes:
Using Adobe Audition (or for those among us that still have Cooledit, I believe this will work just fine) I recorded a piece of LP music to HDD.
Then, I burned it on CD and ripped it again with the same program.
Purpose was of course to find out if any difference was measurable or could be made visible.
Audition has a nifty feature that can detract waveforms.
No need to say that both tracks have to be identical or close to or the thing gives un-interpretable results.
The original recording can be found here:
http://www.pixentral.com/show.php?picture=1G8YxcUUaanjXD4YbJrEbi6ufZfDx
The CD rip is here:
http://www.pixentral.com/show.php?picture=1n8gmnACvwPYUHNYNTe0rQwKVqJebA1
They look very identical and here are the measured differences:
Original recording:
Left Right
Min Sample Value: -12826 -21061
Max Sample Value: 12713 21244
Peak Amplitude: -8.14 dB -3.76 dB
Possibly Clipped: 0 0
DC Offset: -.015 -.015
Minimum RMS Power: -59.23 dB -58.95 dB
Maximum RMS Power: -15.55 dB -12.27 dB
Average RMS Power: -31.12 dB -24.68 dB
Total RMS Power: -29.47 dB -23.02 dB
Actual Bit Depth: 16 Bits 16 Bits
Using RMS Window of 50 ms
Rip:
Left Right
Min Sample Value: -12826 -21061
Max Sample Value: 12713 21244
Peak Amplitude: -8.14 dB -3.76 dB
Possibly Clipped: 0 0
DC Offset: -.015 -.015
Minimum RMS Power: -59.23 dB -58.95 dB
Maximum RMS Power: -15.55 dB -12.27 dB
Average RMS Power: -31.12 dB -24.68 dB
Total RMS Power: -29.47 dB -23.02 dB
Actual Bit Depth: 16 Bits 16 Bits
Using RMS Window of 50 ms
NIL, nothing, nada, nul difference. Not in time, not in amount of samples, not in phase.
So, both tracks should cancel out to zero or very close when deducted.
Here is the deducted waveform:
http://www.pixentral.com/show.php?picture=1mdgtctDbZjgLNIkHP5C8m7lShSQ1D
Note the first 20 seconds of audio. They are indeed about 6db quieter. The rest seems to be simply added.
No, there is nothing wrong with the program or the settings as this is both waveforms added:
http://www.pixentral.com/show.php?picture=1GYfkfgUDtErZjBAVjbVDVrBzhuHyf
Note again the first 20 seconds who appear to be about 6db louder.
If you are still reading, I’m puzzled by these results and unable to find an answer.
So are the guys at Adobe (for the time being)
More to come.
/Hugo
So here goes:
Using Adobe Audition (or for those among us that still have Cooledit, I believe this will work just fine) I recorded a piece of LP music to HDD.
Then, I burned it on CD and ripped it again with the same program.
Purpose was of course to find out if any difference was measurable or could be made visible.
Audition has a nifty feature that can detract waveforms.
No need to say that both tracks have to be identical or close to or the thing gives un-interpretable results.
The original recording can be found here:
http://www.pixentral.com/show.php?picture=1G8YxcUUaanjXD4YbJrEbi6ufZfDx
The CD rip is here:
http://www.pixentral.com/show.php?picture=1n8gmnACvwPYUHNYNTe0rQwKVqJebA1
They look very identical and here are the measured differences:
Original recording:
Left Right
Min Sample Value: -12826 -21061
Max Sample Value: 12713 21244
Peak Amplitude: -8.14 dB -3.76 dB
Possibly Clipped: 0 0
DC Offset: -.015 -.015
Minimum RMS Power: -59.23 dB -58.95 dB
Maximum RMS Power: -15.55 dB -12.27 dB
Average RMS Power: -31.12 dB -24.68 dB
Total RMS Power: -29.47 dB -23.02 dB
Actual Bit Depth: 16 Bits 16 Bits
Using RMS Window of 50 ms
Rip:
Left Right
Min Sample Value: -12826 -21061
Max Sample Value: 12713 21244
Peak Amplitude: -8.14 dB -3.76 dB
Possibly Clipped: 0 0
DC Offset: -.015 -.015
Minimum RMS Power: -59.23 dB -58.95 dB
Maximum RMS Power: -15.55 dB -12.27 dB
Average RMS Power: -31.12 dB -24.68 dB
Total RMS Power: -29.47 dB -23.02 dB
Actual Bit Depth: 16 Bits 16 Bits
Using RMS Window of 50 ms
NIL, nothing, nada, nul difference. Not in time, not in amount of samples, not in phase.
So, both tracks should cancel out to zero or very close when deducted.
Here is the deducted waveform:
http://www.pixentral.com/show.php?picture=1mdgtctDbZjgLNIkHP5C8m7lShSQ1D
Note the first 20 seconds of audio. They are indeed about 6db quieter. The rest seems to be simply added.
No, there is nothing wrong with the program or the settings as this is both waveforms added:
http://www.pixentral.com/show.php?picture=1GYfkfgUDtErZjBAVjbVDVrBzhuHyf
Note again the first 20 seconds who appear to be about 6db louder.
If you are still reading, I’m puzzled by these results and unable to find an answer.
So are the guys at Adobe (for the time being)
More to come.
/Hugo
Tom, you might be right but interestingly, I recorded another track twice (from LP) and matched both as close as it possibly gets in start and ending of the pieces.
Both have exactly the same samples and start and stop at exactly the same time. (as exact as I can do it)
Comparing both Amplitude Statistics gives quite a bit of difference as seen below, anyway more than the ones in the above post which are identical.
Amazingly, the subtract function works pretty good, I have a clear picture of the differences in waveform from both samples.
Sample1
Left Right
Min Sample Value: -16144 -21447
Max Sample Value: 15936 19965
Peak Amplitude: -6.15 dB -3.68 dB
Possibly Clipped: 0 0
DC Offset: -.015 -.015
Minimum RMS Power: -54.59 dB -54.24 dB
Maximum RMS Power: -13.98 dB -12.22 dB
Average RMS Power: -29.59 dB -27.16 dB
Total RMS Power: -28.09 dB -25.54 dB
Actual Bit Depth: 16 Bits 16 Bits
Using RMS Window of 50 ms
Sample2
Left Right
Min Sample Value: -15976 -21645
Max Sample Value: 16076 20063
Peak Amplitude: -6.18 dB -3.6 dB
Possibly Clipped: 0 0
DC Offset: -.015 -.015
Minimum RMS Power: -53.37 dB -54.87 dB
Maximum RMS Power: -13.99 dB -12.17 dB
Average RMS Power: -29.59 dB -27.15 dB
Total RMS Power: -28.09 dB -25.53 dB
Actual Bit Depth: 16 Bits 16 Bits
Using RMS Window of 50 ms
I believe but will check again that the original recording and the rip match even closer.
If you really mean the amount of samples in both tracks, they are identical: 18763080
/Hugo
Both have exactly the same samples and start and stop at exactly the same time. (as exact as I can do it)
Comparing both Amplitude Statistics gives quite a bit of difference as seen below, anyway more than the ones in the above post which are identical.
Amazingly, the subtract function works pretty good, I have a clear picture of the differences in waveform from both samples.
Sample1
Left Right
Min Sample Value: -16144 -21447
Max Sample Value: 15936 19965
Peak Amplitude: -6.15 dB -3.68 dB
Possibly Clipped: 0 0
DC Offset: -.015 -.015
Minimum RMS Power: -54.59 dB -54.24 dB
Maximum RMS Power: -13.98 dB -12.22 dB
Average RMS Power: -29.59 dB -27.16 dB
Total RMS Power: -28.09 dB -25.54 dB
Actual Bit Depth: 16 Bits 16 Bits
Using RMS Window of 50 ms
Sample2
Left Right
Min Sample Value: -15976 -21645
Max Sample Value: 16076 20063
Peak Amplitude: -6.18 dB -3.6 dB
Possibly Clipped: 0 0
DC Offset: -.015 -.015
Minimum RMS Power: -53.37 dB -54.87 dB
Maximum RMS Power: -13.99 dB -12.17 dB
Average RMS Power: -29.59 dB -27.15 dB
Total RMS Power: -28.09 dB -25.53 dB
Actual Bit Depth: 16 Bits 16 Bits
Using RMS Window of 50 ms
I believe but will check again that the original recording and the rip match even closer.
If you really mean the amount of samples in both tracks, they are identical: 18763080
/Hugo
I found the problem.
Although both tracks had the same sample count they were slightly mismatched in time.
I was able to find that with the ‘Find next zero crossing’ tool.
There is a difference of 132 samples between the first zero cross in both tracks.
I then took an equal amount of samples from that point on (18678327) in both tracks and now they match perfectly.
When detracting, the result is absolute silence. (-591db or as low as the graph can show) So the conclusion would be that burning audio on CDRom does in no way alter the music.
I believe I can claim that apart from the different medium they will be played from (cd player or HDD), it is impossible to hear any difference.
So, part of this acid test has been solved. http://www.diyaudio.com/forums/showthread.php?postid=989486#post989486
The other part – proof with data – that an LP and the copy on CD sound equal (or not) is AFAIK virtually impossible.
/Hugo
Although both tracks had the same sample count they were slightly mismatched in time.
I was able to find that with the ‘Find next zero crossing’ tool.
There is a difference of 132 samples between the first zero cross in both tracks.
I then took an equal amount of samples from that point on (18678327) in both tracks and now they match perfectly.
When detracting, the result is absolute silence. (-591db or as low as the graph can show) So the conclusion would be that burning audio on CDRom does in no way alter the music.
I believe I can claim that apart from the different medium they will be played from (cd player or HDD), it is impossible to hear any difference.
So, part of this acid test has been solved. http://www.diyaudio.com/forums/showthread.php?postid=989486#post989486
The other part – proof with data – that an LP and the copy on CD sound equal (or not) is AFAIK virtually impossible.
/Hugo
Yes, of course, unless you have real read/write errors (that don't happen with non defect medias) the music will not be altered. All these are digital copies, only errors can change the data.
So, why do they sometimes sound different ? One would expect no difference... The answer is jitter, "cheap" players seem to not reclock the signal received from the laser pickup.
This means, playing back exactly the same data played through different chains/medias can sound different.
A more interesting test would be to burn the wave onto a cdr, play it back on a cd-player an re-record it through SP/DIF.
Chances are 99.9999% that the result is again identical. (if soundcard does not resample to other samplerate, most cards can only work with 48khz and resample everything else...
)
Mike
So, why do they sometimes sound different ? One would expect no difference... The answer is jitter, "cheap" players seem to not reclock the signal received from the laser pickup.
This means, playing back exactly the same data played through different chains/medias can sound different.
A more interesting test would be to burn the wave onto a cdr, play it back on a cd-player an re-record it through SP/DIF.
Chances are 99.9999% that the result is again identical. (if soundcard does not resample to other samplerate, most cards can only work with 48khz and resample everything else...
)Mike
Okay, i was assuming not comparing with different DACs, these have definitely big differences in sonics.
Sometimes there is the effect that a copied CD sounds different than the original, this is something that should not be possible with digital sound.
Not to be mistaken with cryogenic treated DVDs, giving a better image quality with more alive colors and better contrast...
Mike
Sometimes there is the effect that a copied CD sounds different than the original, this is something that should not be possible with digital sound.
Not to be mistaken with cryogenic treated DVDs, giving a better image quality with more alive colors and better contrast...
Mike
Very interesting experience. I think if you are comparing on the computer visually, then you compare the data samples, and if the timing is aligned, there is no difference. But when you copy, I am not sure whether the data is in the same sequence or whether the burn quality is the same. If the burn quality is not the same, might there be some resampling until the data gets read without error? This would effect the power requirements and all that inter related effects, wouldn't it?
Yeah; I did a similar experiment (except I wrote a little program to find the offset between the original and the copy and do the comparison ).
Surprise, it just works...
Actually what you rip is what you burn. It just works... the only causes for trouble are scratches, and really crap blanks like no-name "brand X" CDRs which will erase themselves if exposed to the sun for a few hours...
When I see some commercial blurb about a transport saying how it has a stable heavy platter ensuring perfect read from the CD, it just makes me feel sorry for the poor uninformed guys who will spend $$$ on this, when a $20 computer CD drive can extract audio at 20x speed without any bit error.
Surprise, it just works...
Actually what you rip is what you burn. It just works... the only causes for trouble are scratches, and really crap blanks like no-name "brand X" CDRs which will erase themselves if exposed to the sun for a few hours...
When I see some commercial blurb about a transport saying how it has a stable heavy platter ensuring perfect read from the CD, it just makes me feel sorry for the poor uninformed guys who will spend $$$ on this, when a $20 computer CD drive can extract audio at 20x speed without any bit error.
Netlist said:Mike,
I have no SPDIF out from the CD player.
I guess optical won't do? Sorry to ask, don't know much about digital.
-=Hugo=-
Hugo, Optical/Coax are both the same signal, and can be converted with leds/photosensitive devices.
I can do the test, i have spdif at player and soundcard.
Soongsc, the moment data is resampled, it's no longer a digital copy and there was a read error. Digital means that there are 0 and 1 only, nothing between. Digital can't degrade. Because of this, it can be copied as often as you want.
peufeu, very good point !
Mike
So I put the disk in my player and connected to optical out to the optical in of the soundcard.
Recording is done but its a hell of a time to match both tracks. If that program is freeware I would be most interested to give it a try.
Also, the output of the cd player is hardly adjustable to make both tracks even loud. But I think I'll burn a sine wave on CD to adjust the volume.
Mike,
It would be nice to hear what you found.
/Hugo
Recording is done but its a hell of a time to match both tracks. If that program is freeware I would be most interested to give it a try.
Also, the output of the cd player is hardly adjustable to make both tracks even loud. But I think I'll burn a sine wave on CD to adjust the volume.
Mike,
It would be nice to hear what you found.
/Hugo
You didn't compare an analog signal to a digital one as the title of the thread suggests. You compared two digital signals, one generation apart via the CDR. Your source could just as well have been a commercial CD as an analog disc.
It would be more interesting to compare an analog disc playback to a commercial CD of the same music. Then you can see/hear the difference between the analog and digital playback mechanisms.
I_F
It would be more interesting to compare an analog disc playback to a commercial CD of the same music. Then you can see/hear the difference between the analog and digital playback mechanisms.
I_F
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.