Difference between Analogue and Digital made visible. Not - Page 3 - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 1st October 2006, 04:39 PM   #21
MikeB is offline MikeB  Germany
diyAudio Member
 
MikeB's Avatar
 
Join Date: Apr 2004
Location: Gütersloh
Quote:
Originally posted by Netlist

Mike,
It would be nice to hear what you found.

/Hugo
Hugo, i did that test, but there was something odd...
The rmaa-measuring shows that the signal did not get degraded. I ran rmaa on its own supplied .wav and from cd (with this file burnt) through spdif.

But subtracting the 2 waves (the original and the captured) did not result in exactly zero. Some strange 2-bit noise was left, repeating every 2.7 seconds, having a gap of silence of ~0.7 secs. This noise was in no relation to the original signal.
I am paranoid enough to suspect that some software/hardware added a watermark...

Mike
  Reply With Quote
Old 1st October 2006, 06:16 PM   #22
MikeB is offline MikeB  Germany
diyAudio Member
 
MikeB's Avatar
 
Join Date: Apr 2004
Location: Gütersloh





AAAArgh !

Found the source to the odd noise... I did not use exactly the same wave-file rmaa puts out and the burned one. Rmaa adds white noise to each test pattern to "improve" fft ? This gives different wave file each time it gets generated.
Well, gladly i found the original wavefile that was burnt to cd.
The result: perfect digital zero.

So: Wave file generated -> burnt to CD -> played from player -> recorded via spdif. The result is a perfect digital copy, subtracting the recording with the original wave file gives complete zero, not a single bit lost !

So much about the voodoo, that error correction replaces samples, burning CDs changes the data and so on, bla bla bla. (burnt onto cheapest CDR available, one year ago)

BTW, my spdif coax-cable was a 2meter plain RCA-cable, nothing special/high quality.
The only real thing with the digital-voodoo is jitter, no data is somewhere lost/changed.

Hardware used for the test:
- Burner: LG GSA-4040B
- Player: Pioneer DV-525
- Soundcard: M-Audio Delta 24B96
- Cable: Standard RCA-cable audiophiles would never touch.

All mainstream, except the soundcard maybe.

The result: ALL data gets to the DAC completely unchanged/undegenerated, maybe just not in the exact nanosecond it should.

Mike
  Reply With Quote
Old 1st October 2006, 06:24 PM   #23
Netlist is offline Netlist  Belgium
diyAudio Moderator Emeritus
 
Netlist's Avatar
 
Join Date: Jan 2003
Many thanks for that Mike.
Although many will still argue, I'm glad the data can be carved in stone.
Pretty nice sound card you have there.

/Hugo
  Reply With Quote
Old 1st October 2006, 06:35 PM   #24
MikeB is offline MikeB  Germany
diyAudio Member
 
MikeB's Avatar
 
Join Date: Apr 2004
Location: Gütersloh
Yes, the soundcard is a nice one. I especially bought it for measurings and absolutely wanted spdif coax in/out. Measured thd of this soundcard is ~0.001%.

I hope this test can end many of the debates...
The results are plain and measured effects, no data gets lost or changed in the digital chain. I'm not sure whats left to argue about ? Identical data is identical data, even without high performance hardware.

Mike
  Reply With Quote
Old 1st October 2006, 06:35 PM   #25
rdf is offline rdf  Canada
diyAudio Member
 
rdf's Avatar
 
Join Date: Jun 2004
Location: big smoke
You've proved the strength of error correction but did some still maintain audible differences in digital playback were due to sample error? (BTW, I can't hear a diff between my Toslink or coax connect to a Benchmark DAC.)
  Reply With Quote
Old 1st October 2006, 06:52 PM   #26
MikeB is offline MikeB  Germany
diyAudio Member
 
MikeB's Avatar
 
Join Date: Apr 2004
Location: Gütersloh
That's exactly what i wanted to justify, there is no sample error, if there is an audible difference it is not related to data errors, jitter is the only thing that seems to be responsible or this.
I intentionly used mainstream hardware, if this is able to deliver all data without a single error, high end hardware really should have no problem with that.

Jitter has null effect in this test, as only the datas transfered are compared. (Just like downloading from the internet)

Error correction typically takes place when bits are decoded from disc, but obviously no problem occured during my test. (with a cheap cdr)

Mike
  Reply With Quote
Old 1st October 2006, 07:59 PM   #27
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally posted by soongsc
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?

There will surely be burning or reading errors, often 1000's on a CD. The point is that the error correction correct all this 100% (unless uncorrectable errors cause error concealment but thats really rare these days). The fact that Hugo saw exact copies is a testimony how good the CD system is even with many, many errors occuring.

Jan Didden
__________________
I won't make the tactical error to try to dislodge with rational arguments a conviction that is beyond reason - Daniel Dennett
Check out Linear Audio Vol 7!
  Reply With Quote
Old 1st October 2006, 08:03 PM   #28
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally posted by I_Forgot
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
I don't think that exists. You may have the same piece of music on LP and CD, but I would bet that the mastering and mixing and recording would be done different. In fact, it is my believe (which I cannot prove, but Hugo's and MikeB's findings support it) that the difference between LP and CD is SOLELY due to mastering/mixing etc differences and NOT due to any problems with either medium.

Jan Didden
__________________
I won't make the tactical error to try to dislodge with rational arguments a conviction that is beyond reason - Daniel Dennett
Check out Linear Audio Vol 7!
  Reply With Quote
Old 1st October 2006, 08:06 PM   #29
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally posted by MikeB
That's exactly what i wanted to justify, there is no sample error, if there is an audible difference it is not related to data errors, jitter is the only thing that seems to be responsible or this.
I intentionly used mainstream hardware, if this is able to deliver all data without a single error, high end hardware really should have no problem with that.

Jitter has null effect in this test, as only the datas transfered are compared. (Just like downloading from the internet)

Error correction typically takes place when bits are decoded from disc, but obviously no problem occured during my test. (with a cheap cdr)

Mike

Mike,

Didn't you just prove that S/PDIF jitter also has no effect?? S/PDIF in essence being an analog signal.

Jan Didden
__________________
I won't make the tactical error to try to dislodge with rational arguments a conviction that is beyond reason - Daniel Dennett
Check out Linear Audio Vol 7!
  Reply With Quote
Old 1st October 2006, 08:12 PM   #30
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
I forgot.

Hugo, Mike, this is one of the most relevant threads I have ever seen here (no offense to others, including myself). This really furthers our understanding. Thank you for taking the trouble to figure this out.

Jan Didden
__________________
I won't make the tactical error to try to dislodge with rational arguments a conviction that is beyond reason - Daniel Dennett
Check out Linear Audio Vol 7!
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Analogue vs. Digital RIAA Netlist Analog Line Level 40 21st August 2010 04:27 PM
Analogue v digital XOs rick57 Multi-Way 25 9th May 2007 08:41 PM
Digital vs. Analogue Equalizer ak_47_boy Everything Else 0 20th January 2007 02:40 AM
Hidden clipping made visible. Netlist Digital Source 9 30th January 2006 07:11 AM


New To Site? Need Help?

All times are GMT. The time now is 06:12 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2