You did well in this test. There is only 4 % chance you were just lucky to have 2/3 of the answers correct. I am ready to believe you can tell 320 kbps mp3 and wav apart, which is not impossible for humans, but very few can do. However, even you with your very good ears had 1/3 of the answers wrong which means the difference is extremely small even for you. The question is does the difference matter to you? I'd like to think a difference I can tell correctly 100 % of the time is a real difference that matters. If I get is only 90 % of the time correct it still matters, but less. If I get it correct only 75 % or less of the time, I don't think it matters anymore. The difference is so small I can pretend it doesn't exist. Only when I can tell the differences correctly close to 100 % or 100 % of time do they "matter" and when it is full 100 % the difference matters so much it requires action if possible.
Now, 320kbit mp3 reduces the bit rate of lossless version it was made from dramatically including frequency ranges were human ears is sensitive. That's why it is possible (but very difficult as you yourself demonstrated) to hear some differences. Do the differences matter is another question. From psychological point of view they probably do matter, because human's don't like the feeling that something is inferior to something else. From practical point of view these differences do not matter. When you are on the go in traffic listening to "Smells Like Teen Spirit" you aren't thinking about what the lossy coding did to the sound. You are thinking your daily life things: Problems at work. The need to buy milk. What to give to your girlfriend as the Birthday present. Kane Pixels newest Backroom video. Stuff like that. That's when you are deaf to the defiances to the lossy coding.
Tell me I am full of crap. I know what humans can hear and I understand what matters and when.
the thing.... i hope i somewhat proofed i can do blindtests myself, but each time (vs casual subjective listening) i also notice the culprits of DBT
1. as you say, why i only get 70% right? humans are simple no machines, you guys say it each time on subjectivists but expect machine like results on DBT? (specially if we talk barely audible stuff)
if you do casual listening "you get a feeling" of how the overall sound ist, this doesnt happen after 1 song, but if you like listen for half an hour, IF you switch then only once to B (mp3) and continue to listen (dont ask me why exactly... but i say this to you as someone who did both, blind tests and subjective listening) its way more audible...
2. if i would have gotten no feedback by seeing the results "IN THE TEST", it would have been way harder, either you do "training sessions before hand" without seeing results while the test is running or it makes it pretty much "random"..... tho after all another point that "probably" washes some results out
3. ABX software sound quality
using stuff in windows that utilizes the windows resampling algorithm washes results out, because windows resampling is simply subpar...
its probably not the only potential flaw that could rise from doing "proper A/B tests", just think of a switch box or such
4. rapid switch and fourth
i was doing it naturally, it helped, but i also noticed points where i got 1-2 wrong and simply got really unsure after that (eq see 2. "feedback" which you naturally get while subjective listening because you simply know what is running "you can make sense of how it sounds"), imo its pros and cons with rapid back and fourth switching
i guess someone who really wants to do serious DBT tests can find their own "working" system after a while, but if i imagine random people get stuck in a room "here is a system and a A/B switch, listen to it" i see how potential problems could arise
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Now you can say im eccentric and what not but for me these small changes definitely stack up, specially if i look at the digital side of things i just see why people say "it sounds digital" because it actually does..... transients are subpar, high frequencys harsh because ime mostly ringing and what not
also using EQ is always a compromise, funny subjective story:
i had my EQ set on FIR filtering, looked up roommodes in REW and used this variable online tone generator (
https://www.szynalski.com/tone-generator/ ) to sweep the whole frequency range and make it "FLAT" by ear
now i switched to IIR filtering " Huh? the frequency response is crooked again ", this was my biggest hint that phaseshift really matters how you perceive frequencys
in the end i had to adjust the db values for the IIR filters, so i have the same frequency response as with FIR
i think using REW room mode equaliser calculations are simply off because of the phaseshift, i got way better results by doing it per ear
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From practical point of view these differences do not matter. When you are on the go in traffic listening to "Smells Like Teen Spirit" you aren't thinking about what the lossy coding did to the sound. You are thinking your daily life things: Problems at work. The need to buy milk. What to give to your girlfriend as the Birthday present. Kane Pixels newest Backroom video. Stuff like that. That's when you are deaf to the defiances to the lossy coding.
you are right, "in practise" it doesnt matter more often than not
tho what is in practise? for me in practise is sitting on my PC setup in the sweet spot, i also hear high frequency changing quite alot (just wiggle back and forth half an meter and you get an nice sound effect lol) tho now imagine the exact same sound effect but -0.5db reduced..... its audible if you know what to listen for...
tho if i wanna know what is audible i dont add 10 variables that could "smear" what im actually testing, i test the one thing as good as possible to see whether this could smear other things