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64 vs. 128 vs/ 256 MP3 listening test in Cognitive Daily

post #1 of 16
Thread Starter 
Interesting.

Cognitive Daily: Few listeners can distinguish between "average" and "best" MP3 samples

Summary:

Their results: 64 kbps worse than 128 kbps, 128 kbps usually not distinguished from 256 kbps.

Audiophiles slightly better on testing than non-audiophiles.

The test metholodolgy is much-maligned in some quarters, because they did not use the original lossless samples in the testing, if I understand correctly. Thus, it's not true ABX testing.
post #2 of 16
Anyway, they didn't ask for ABX, even between the mp3 themselves.

The result is not surprising, given that no special attention was required from the listeners. In casual blind tests, results are usually not as good as in blind tests where audio compression geeks take part.

I downloaded the six samples (using the code of the webpage to find their URL) and decoded them to wav.
Note that the Santana sample is heavily clipping. One of the mp3 reach more than +1.4 dB during decoding. This may help identifying the samples even without listening to compression artifacts.
So I used Foobar2000 to decode them 2 dB below their original volume, so that they don't clip.

I successfully ABXed the samples 1 vs 2, 2 vs 3 and 3 vs 1 for both Santana (unclipped) and Copland. 8/8 every time.

The 128 kbps artifacts are quite audible in Santana. They are also audible in Copland everywhere, but it needs more concentration. I listened to the pre-echo on piano attacks.
ABXing Copland 128 kbps vs 256 kbps took me around 10 minutes. Santana was done in 2 or 3 minutes, and the four 64 kbps tests were done in less than 20 seconds each.

I wonder if they used a good encoder. Maybe it is possible to get a better result than that at 128 kbps.
post #3 of 16
this test only proves what it proves - the statistics of who is aware or has refined their listening to that extent

nothing new - and nothing surprising. people are used to listening to music at 96 and 128 - it's by far the most common rate, and lines up perfectly with the demographics who are unable to discern
post #4 of 16
Quote:
Originally Posted by Luminette View Post
the statistics of who is aware or has refined their listening to that extent
...or who pretends to hear it !
post #5 of 16
Guess I am one of those "few".
Cause I have no problem distinguish 64Kbps from 128Kbps MP3 files..
post #6 of 16
64 kbps & 128 kbps is most easy to distinguish..if u cant then u r an insult to the creator of Human ear.
post #7 of 16
Quote:
Originally Posted by Steve999 View Post
The test metholodolgy is much-maligned in some quarters, because they did not use the original lossless samples in the testing, if I understand correctly. Thus, it's not true ABX testing.
it's not the lack of original sample that invalidates this test but the fact that both the 64 and the 128 samples were later transcoded to 256, thereby lossily encoded twice. as a result the difference between 64 and 128 in that test is harder to discern than "in the real world".

i still managed to correctly identify 64 from 128 in both samples (i didn't do foobar abx, so i might have just guessed correctly, but both 64 samples sounded off to me) BUT i clearly preferred the 128 santana to the 256. ironically that was the only decision i had been absolutely sure of
apparently i was not alone there... interesting. is that a known phenomenon? does encoding twice perhaps smooth over some of the rough stuff?
post #8 of 16
Quote:
Originally Posted by Nocturnal310 View Post
64 kbps & 128 kbps is most easy to distinguish..if u cant then u r an insult to the creator of Human ear.
...really?
post #9 of 16
Quote:
Recently Amazon.com launched a digital music service which boasted 256 kbps MP3s, instead of the 128 kbps files more common at other sites. Are they simply wasting our disk space? So far these results suggest they are. But there are a few other possibilities.
These ignorants who listen to music through cheap earphones are damaging music industry... because of these people most Online Stores dont bother selling music at high bit rate anymore.

even illegal music is in low bit rate so cant sample anymore.
post #10 of 16
Quote:
Originally Posted by malldian View Post
...really?
There should be a listening test for all Head-fi members.

those who dont pass the 64 kbps v/s 128 kbps test shouldnt be allowed to post and only read


I am kidding with an underlying message
post #11 of 16
It's surprising how good LAME 128kbps really is. On poorly/commonly recorded music, it's no surprise download sites choose it. It's really quite adequate, to people for whom a concept of 'adequate quality' exists. Most people around here are like OMG CAN ABX DO NOT WANT.
post #12 of 16
Quote:
Originally Posted by Nocturnal310 View Post
These ignorants who listen to music through cheap earphones are damaging music industry... because of these people most Online Stores dont bother selling music at high bit rate anymore.

even illegal music is in low bit rate so cant sample anymore.
I get the part where there's not many people who download high'er' bit rate music and illegal music not supporting the music industry.

But calling people 'ignorant' because they listen music through cheap earphones...? and 'them' damaging the music industry...?

Why did you say that?
post #13 of 16
Quote:
Originally Posted by trains are bad View Post
It's surprising how good LAME 128kbps really is. On poorly/commonly recorded music, it's no surprise download sites choose it. It's really quite adequate, to people for whom a concept of 'adequate quality' exists. Most people around here are like OMG CAN ABX DO NOT WANT.
I see where you're coming from. A lot of people who use only lossless couldn't tell 192 from lossless in an ABX I suspect. When I download something I'm happy with 160kbps. But if it's something I like, I'll download a higher bitrate. That said, I'm amazed there were some people who couldn't tell 64kbps from the others. You'd have to be really deaf to miss that, or have equipment built by angry baboons.
post #14 of 16
Quote:
But calling people 'ignorant' because they listen music through cheap earphones...? and 'them' damaging the music industry...?
Why did you say that?
Because he's premature ejaculator whos been adviced many times to be more humble and not to show his own lack of knowledge and experience. Yet, he continues to show himself in a bad light...
post #15 of 16
Quote:
Originally Posted by Akabeth View Post
I get the part where there's not many people who download high'er' bit rate music and illegal music not supporting the music industry.

But calling people 'ignorant' because they listen music through cheap earphones...? and 'them' damaging the music industry...?

Why did you say that?
Quote:
Originally Posted by QQQ View Post
Because he's premature ejaculator whos been adviced many times to be more humble and not to show his own lack of knowledge and experience. Yet, he continues to show himself in a bad light...
Ugh, him again. Ever since the beginning Nocturnal310 has been ignorant in what he talks about, and after people correct him, he leeches that knowledge to bash other people and tries to feel superior to those who haven't been lucky enough to stumble upon this website yet.

Sickens me to the core.
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