So, let's go
First :
- did I say that AAC 320 is in the developer statements, or would be better than AAC 256 ?
Never, I only told you that Tidal was using AAC 320 VBR until now
(which may change as they start to use 160 now that they are seperating turning Hifi into AAC+FLAC(and MQA 16bit) and Hifi Plus AAC+FLAC+MQA (16 and 24bit)+Atmos+360°)
- did I say that converting a 64kbps to a 256kbps file would give a better file ? or do I need to understand that ?
Never, because it would be stupid to think so, and it doesn't prove anything between a 256 and a 512 file (you have to use a higher original one, not a lower one).
So, try to prove what you want, you're free to do it, but please, stop playing with words to make people saying something they didn't
Second, better (and faster in this case) than reading a lot of papers : a test that may not be perfect, but that you could have easily done yourself before assuming other people are wrong (when again, they never said such a thing, because I never did this test before) :
1 - I took the first FLAC I found in my computer, a 24/192 file (not sure if it's the best to test, as/but it adds downsampling in the conversion process). If needed, I can do it again with a 16/44.1 FLAC file.
2 - I used Foobar (it uses iTunes library if I'm not wrong) to convert it to 4 AAC files with different bitrates : VBR320 - VBR256 - CBR512 - CBR256.
I also did VBR in case it'd be needed later, but the last two (in bold) are the one to test as you said there is no difference between AAC 256 and AAC 512, which is certainly right (it may be worst, would need a test to confirm it) if you convert a AAC 256 to a AAC 512 as it won't recover any information lost at first, but may be wrong from FLAC to AAC 512 and AAC 256
So let's see the files : as the original was a 192kHz file, the conversion gave 48kHz AAC files
It appeared that the bitrate of the CBR512 was actually 320kbps, so maybe it doesn't go over 320 even if we select 512.
View attachment 167874
Let's forget about VBR, and just look at the 256 and 512 (which is actually only 320) : DeltaWave difference test :
View attachment 167878
To compare, doing a Digital->Analog then Analog-Digital loopback recording with one of my audio interfaces gives me more than twice a better result than that...
Would it be heard by all people, I don't know and it's not the subject of what you were saying, but regarding the "no difference" like you said, it appears that there are differences (unless I made a big mistake )
...considering the fact that the question has began with my mistake, just let me refer to it first.
I've mentioned a placebo effect and this MP3 to WAV conversion because I've meant the audible difference. That's the purpose of higher quality right? To be able to actually hear it. I could test it with my ears though but I know it wouldn't be any proof for you guys, and while you've mentioned the ABX test which I'm not familiar with yet, it would be good if someone could clear this case up once and for all.
Last edited: