What is wrong with op-amps?

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#542
Jay said:
I just made a smaller DB difference to see if the file size and SHA changes or not. I made 0.51dB difference and the file size didn't change! So is the SHA! But they sound different in FoobarABX...

I haven't read your post, I couldn't focus on the ABX (my son was pulling my hand for the walk around routine) so the result was 7/8 but it should show that I heard differences.
Click to expand...


You achieved 7/8 correct on two identical files. Either there is a bug in the code that manages to subtlety degrade one of the files (which would be extremely difficult to accidentally code and a disaster for someone writing ABX software) OR you just managed to achieve something that could only happen with ~1/128 probability OR ???

How could you have achieved this miraculous achievement with two identical files?
 
#543
foobar sometimes plays first track on lower volume than second , never managed to find out why.also sometimes all tracks would sound low volume then only re-connect of my soundcard would fix it,happened with different brands of soundcards.
probably has something to do with replaygain?
edit: i hope you are using wasapi for tests.
 
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#547
For what it's worth, I loaded the posted files into my venerable, registered version of Cool Edit 2000 and got the following numbers from the Analyze/Statistics... function (I deleted "Using RMS Window of 50 ms" from each set of numbers). Identical sets of numbers jibe with what others said are identical files:

Norah1.mp3
Mono
Min Sample Value: -18008
Max Sample Value: 26898
Peak Amplitude: -1.71 dB
Possibly Clipped: 0
DC Offset: 0
Minimum RMS Power: -43.4 dB
Maximum RMS Power: -10.71 dB
Average RMS Power: -21.8 dB
Total RMS Power: -20.4 dB

Norah2.mp3
Mono
Min Sample Value: -18008
Max Sample Value: 26898
Peak Amplitude: -1.71 dB
Possibly Clipped: 0
DC Offset: 0
Minimum RMS Power: -43.4 dB
Maximum RMS Power: -10.71 dB
Average RMS Power: -21.8 dB
Total RMS Power: -20.4 dB

Norah.mp3
Mono
Min Sample Value: -7572
Max Sample Value: 11309
Peak Amplitude: -9.24 dB
Possibly Clipped: 0
DC Offset: 0
Minimum RMS Power: -50.93 dB
Maximum RMS Power: -18.23 dB
Average RMS Power: -29.32 dB
Total RMS Power: -27.92 dB

FX8-Bimo-Clip-2splmod.mp3
Mono
Min Sample Value: -17206
Max Sample Value: 27591
Peak Amplitude: -1.49 dB
Possibly Clipped: 0
DC Offset: 0
Minimum RMS Power: -49.49 dB
Maximum RMS Power: -12.08 dB
Average RMS Power: -22.89 dB
Total RMS Power: -21.34 dB

FX8-Bimo-Clip-2splmoddB51.mp3
Mono
Min Sample Value: -17206
Max Sample Value: 27591
Peak Amplitude: -1.49 dB
Possibly Clipped: 0
DC Offset: 0
Minimum RMS Power: -49.49 dB
Maximum RMS Power: -12.08 dB
Average RMS Power: -22.89 dB
Total RMS Power: -21.34 dB

Nora-a.mp3
Left Right
Min Sample Value: -17681 -17681
Max Sample Value: 25926 25926
Peak Amplitude: -2.03 dB -2.03 dB
Possibly Clipped: 0 0
DC Offset: .001 .001
Minimum RMS Power: -104.31 dB -104.31 dB
Maximum RMS Power: -10.91 dB -10.91 dB
Average RMS Power: -22.3 dB -22.3 dB
Total RMS Power: -20.46 dB -20.46 dB

Nora-b.mp3
Left Right
Min Sample Value: -18093 -18093
Max Sample Value: 26530 26530
Peak Amplitude: -1.83 dB -1.83 dB
Possibly Clipped: 0 0
DC Offset: .001 .001
Minimum RMS Power: -104.18 dB -104.18 dB
Maximum RMS Power: -10.71 dB -10.71 dB
Average RMS Power: -22.1 dB -22.1 dB
Total RMS Power: -20.26 dB -20.26 dB
 
#550
bear said:
It's interesting, since I have the delusion that I (and others who enter my world of delusion and hallucination) can hear differences in opamps.

So, I'm assuming that I am using them "improperly" and I want to not do that. If you could explain how to not use them "improperly" then I can do that and perhaps revise my thinking on this matter??

Perhaps an example for two given opamps of your choice would suffice?
Click to expand...

What you are asking now is what I was asking. I'm not the one who says "opamp rolling is wrong because you can't put any opamp in any circuit and expect them to work within their limits." Of course, that statement is true, but I'm agree to those who said that where ever you bring the opamp (and I have tried many), the opamp seems to bring its own sound signature...
 
#552
dontbugme said:
How could you have achieved this miraculous achievement with two identical files?
Click to expand...

Well, it is a test of intelligence and integrity for all of you 😀

I don't know the answer, but there are many possibilities... Right now, the most probable answer came from tonitonitoni (but I think Mark also has mentioned this but I couldn't believe that):

tonitonitoni said:
foobar sometimes plays first track on lower volume than second , never managed to find out why.
Click to expand...

I cannot see other possibility, especially after I followed Mark advise to randomize the way I name, order and attach the file to Foobar. I made 66.mp3 for a file that as far as I remember was the louder file (FX8*moddB52.asc) and 77.mp3 for the softer file. And guess what, I got 2/8 twice in a row!

I still thought that I might mistakenly thought that the louder one was the softer one, but reading tonitonitoni experience, then I'm 99% sure that this is the case with Foobar.
 
#553
Brett said:
Show me the evidence that ANY human can hear a 0.01dB difference in level blind.
Click to expand...

As I used FoobarABX when I tested my threshold for level difference (and the result was far below what has been found by Toole and Olive), and now it seems that Foobar has a bug, then I temporarily doubt that I can hear 0.1dB difference.

Any suggestion for better/trusted software for ABX?
 
#555
bear said:
This is a blatant hijack - this bit about hearing file diffs belongs in a different thread.
Click to expand...

May be you're right, Bear. But certain topics cannot just last long. Many of it are just duplicates. For example, people had mentioned the reasons why opamp might not be a good option, for many times, and often people don't learn anything.

Even the OP, after reading the opamp blind test found out that he couldn't find something useful there:

scott wurcer said:
http://www.diyaudio.com/forums/chip...-audio-integrated-opamps-227.html#post4836625
Click to expand...

🙂
 
#557
Markw4 said:
Here are two files that should differ in level by 0.2 db. That's the way I set them, but haven't double checked. Change the file type to wav.

Edit: I just double checked and one file is 0.2 different from the other.
Click to expand...

Thanks, Mark. I may need those files later. Right now I have only Foobar and I think it would be easy to ABX your file with Foobar...

But I can try to put the files in certain order to bypass the predicted bug of Foobar (as stated by tonitonitoni). That will be interesting too 🙂

BTW, Norah file is not the right one to test level threshold. I used it because it is the smallest audio file I have in my computer.

It took me a long time (may be hours) until I found which segment to use for the ABX. There is only one segment around the middle, and the earlier segment where Norah sing "Come away with me"
 
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#559
If one has a related but tangential topic, just start a new thread and link to it.
Simple, easy and has been done many times before.

Should the original topic die out, then it does - interestingly some rather old topics
do get revived. If the entire subject is trashed, that won't happen either.
 
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