How Well Can You Hear Audio Quality?

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tortugaranger

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How Well Can You Hear Audio Quality?
« on: 27 Jun 2015, 07:33 pm »
Came across this on the NPR.org website and gave it whirl.
http://www.npr.org/sections/therecord/2015/06/02/411473508/how-well-can-you-hear-audio-quality

They present several tunes in 128k MP3, 320k MP3, and WAV (full CD Redbook) and ask you to listen to each and pick the highest quality version. They tell you which one your picked.

Interesting results from taking the test:
1) 100% of the time I never picked the 128k
2) 2 of out 6 times I picked 320k over WAV
3) I got the same results both on an iPAD and on my main stereo rig.

Conclusions?
a) 128k MP3's clearly suck and I could clearly tell they suck
b) Although the sample size was small it appears I had roughly a 50/50 chance of picking full rez over 320k (i.e. no discernible difference)
c) My stereo rig must really suck or else I would have clearly picked the WAVs
d) My hearing is shot

The kind of stuff that makes some heads explode but it sure would be interesting to see the results of something like this with a large sample size and various independent variables. For the record, all of my digital stuff is FLAC and some of that is hi-rez.   :thumb:

konut

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Re: How Well Can You Hear Audio Quality?
« Reply #1 on: 27 Jun 2015, 11:14 pm »
The problem with these kinds of "tests" is that the apparent differences are highly dependent on the program material itself.  For example, some of the most  readily apparent differences in in different compression schemes are reverb tails. If the program materiel has no reverb, then the test is of limited use. By using
 FLAC there is never any question that one is missing information, no matter what the program material.

Folsom

Re: How Well Can You Hear Audio Quality?
« Reply #2 on: 27 Jun 2015, 11:40 pm »
I can tell the 128 vs. the others on all but one track... With my half broken laptop speakers. They're mostly bad recordings so even on a great computer it'd be hard to tell, especially going through bit degradation of windows kernal.

kingdeezie

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Re: How Well Can You Hear Audio Quality?
« Reply #3 on: 27 Jun 2015, 11:49 pm »
There is something bogus about this test.

First off, they don't tell you if the different files are from the same master. Did the author rip each one of these files from a CD at different bitrates and levels of compression?

My brother, who has a nice headphone rig, minus a quality DAC (last piece he needs), showed me this last week.

The Coldplay song on the 320K version had such bad background distortion through his rig. It sounded like a bad MP3 rip. The 128k file actually had significantly less background noise and hash, which makes zero sense.

It didn't sound like the same source, unless it was an issue with whatever internet plug in plays the file, which probably also skews the resulting sound.

I wouldn't put to much stock in the results.

srb

Re: How Well Can You Hear Audio Quality?
« Reply #4 on: 28 Jun 2015, 02:11 am »
I have to wonder about the integrity of the source files.  All of the files sound like lower resolution versions with reduced clarity, and for some reason also reduced high frequency content.  They don't sound nearly as good as my own 16/44.1 files, and I have 128kbps to 320kbps files that sound better than their WAV samples.

It just seems that something may have somehow gone very wrong with the creation, execution or posting of the samples, which might explain the more subtle differences between them and the overall lack of excellent fidelity of even the WAV files.

Either that, or because I don't have any of those tracks for comparison, maybe the production standard of these particular chosen albums is very low?

Steve

tortugaranger

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Re: How Well Can You Hear Audio Quality?
« Reply #5 on: 28 Jun 2015, 05:24 pm »
The challenge with any such "tests" is the credibility of the source material which can quickly become the focus point rather than the overall objective of the test of itself. I think it would be very interesting indeed if someone were to set up a well documented above reproach version of this test concept and set it loose on the audiophile community. I'd be very curious to seen the results after 100's if not 1000's of people took a crack at it.