Blind test: 6 DACs compared
post-9117713
Post #92 of 176

Hi Rez

100+ Head-Fier
Joined
Oct 16, 2012
Messages
203
Reaction score
26
Joined
Oct 16, 2012
Posts
203
Likes
26
Quote:
Nothing special: I extracted a 30 seconds sample from a 16 bit / 44.1 kHz track that was ripped from a CD.
More specifically, what utility did you use to extract the sample?
 
     Share This Post       
post-9118322
Post #94 of 176

nick_charles

Headphoneus Supremus
Joined
Feb 26, 2008
Messages
3,180
Reaction score
333
Joined
Feb 26, 2008
Posts
3,180
Likes
333
I tried listening tests and could not distinguish between any of them. Then I used Audacity to do a spectrum analysis on each. I exported the data as text and imported it into Excel, then I graphed the FR in Excel for each DAC I had 1023 data points. All 6 lines were different but they were all also the same (give or take) until you hit about 19 - 20K, at which point the signal is at -70db that is none of the DACs showed anything that could be regarded as a different signature in frequency terms up to 19K. Taking the min and max energy levels at each frequency and the differences between them (absolute values)  and charting them showed that the difference between quietest and loudest did not reach 1db until 11K (-53db). the differences between the traces below 20K could easily be ascribed to variance in the recording (AD process) and level matching from the sources.
 
     Share This Post       
post-9118504
Post #95 of 176

Hi Rez

100+ Head-Fier
Joined
Oct 16, 2012
Messages
203
Reaction score
26
Joined
Oct 16, 2012
Posts
203
Likes
26
So six of the samples were recorded with the EMU 0204 USB, and all seven were edited with Audacity.  Did you use the identical Audacity preference settings for all edits?
 
Seems it would be difficult to unequivocally rule out potential effects from the EMU 0204 USB or Audacity.
 
     Share This Post       
post-9118521
Post #96 of 176

chewy4

Headphoneus Supremus
Joined
Jun 27, 2011
Messages
1,591
Reaction score
76
Joined
Jun 27, 2011
Posts
1,591
Likes
76
Quote:
So six of the samples were recorded with the EMU 0204 USB, and all seven were edited with Audacity.  Did you use the identical Audacity preference settings for all edits?
 
Seems it would be difficult to unequivocally rule out potential effects from the EMU 0204 USB or Audacity.
Why would that be difficult?
 
     Share This Post       
post-9118557
Post #98 of 176

chewy4

Headphoneus Supremus
Joined
Jun 27, 2011
Messages
1,591
Reaction score
76
Joined
Jun 27, 2011
Posts
1,591
Likes
76
Quote:
How would one conclusively test it?
As for making sure Audacity isn't adding any effects... Just don't turn on any effects...
 
As for the recording device(this goes for Audacity as well), if you can't pick out the original sample it's obviously not a problem.
 
     Share This Post       
post-9118572
Post #99 of 176

skamp

Aka: HeadFiend, BatFi
Joined
Oct 8, 2008
Messages
1,334
Reaction score
93
Joined
Oct 8, 2008
Posts
1,334
Likes
93
Seems it would be difficult to unequivocally rule out potential effects from the EMU 0204 USB or Audacity.

You're welcome to provide ABX logs demonstrating that the recordings are audibly different.
 
     Share This Post       
post-9118581
Post #100 of 176

Hi Rez

100+ Head-Fier
Joined
Oct 16, 2012
Messages
203
Reaction score
26
Joined
Oct 16, 2012
Posts
203
Likes
26
Quote:
As for making sure Audacity isn't adding any effects... Just don't turn on any effects...
 
As for the recording device(this goes for Audacity as well), if you can't pick out the original sample it's obviously not a problem.
With any digital editor, even adjusting the volume levels requires bit manipulation and dithering.
 
But the original sample was edited with Audacity....
 
     Share This Post       
post-9118589
Post #101 of 176

nick_charles

Headphoneus Supremus
Joined
Feb 26, 2008
Messages
3,180
Reaction score
333
Joined
Feb 26, 2008
Posts
3,180
Likes
333
Quote:
You're welcome to provide ABX logs demonstrating that the samples are audibly different.
 
 
The possible (devils advocate)  problem is that the recording process may obscure differences. We assume that the recording device/software is accurate to 16 bits but even so if the differences between the analog outputs are very slightly different the quantization process has inherent (low order bit) errors and could obscure small differences. My take on this is that if real differences between two DACs are obscured by a 16 bit AD process then they are not differences worth worrying about. But the critics can say "of course I can hear the difference between two nominally flat 16 bits DACs but not when there is a 2nd AD stage"  - I went through all of this when i did my cable tests...
 
     Share This Post       
post-9118592
Post #102 of 176

chewy4

Headphoneus Supremus
Joined
Jun 27, 2011
Messages
1,591
Reaction score
76
Joined
Jun 27, 2011
Posts
1,591
Likes
76
Quote:
With any digital editor, even adjusting the volume levels requires bit manipulation and dithering.
 
But the original sample was edited with Audacity....
Why would he even adjust anything like that?
 
And why would it matter if the original sample had any alterations, if the others were recorded from it being played?
 
Just to be clear, you are worried about inconsistencies causing audible differences that shouldn't be there, right?
 
     Share This Post       
post-9118607
Post #103 of 176

nick_charles

Headphoneus Supremus
Joined
Feb 26, 2008
Messages
3,180
Reaction score
333
Joined
Feb 26, 2008
Posts
3,180
Likes
333
Quote:
With any digital editor, even adjusting the volume levels requires bit manipulation and dithering.
 
But the original sample was edited with Audacity....
 
 
In another thread in this subforum we saw some evidence that even converting a 24 bit file to 16 bits with the worst possible type of dither and truncation did not do any audibly detectable damage...
 
     Share This Post       
post-9118623
Post #104 of 176

Hi Rez

100+ Head-Fier
Joined
Oct 16, 2012
Messages
203
Reaction score
26
Joined
Oct 16, 2012
Posts
203
Likes
26
Quote:
Why would he even adjust anything like that?
 
And why would it matter if the original sample had any alterations, if the others were recorded from it being played?
 
Just to be clear, you are worried about inconsistencies causing audible differences that shouldn't be there, right?
skamp matched the volume levels of all the recordings so differing volume levels would not influence the test.
 
Hypothetically, If the "sound" of the original sample could have been influenced by the editor, and then all the recordings made from it were then similarly influenced by the same editor.  Not saying it happened, just asking how one can rule it out.
 
Actually I am not worried about audible differences that shouldn't be there.  In my first post I stated that I didn't hear any....
 
     Share This Post       

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top