AAC 256 VS AAC 320
Jan 23, 2023 at 2:39 PM Thread Starter Post #1 of 22

trivium911

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Hey Guys,

I’ve proven that I can’t tell the difference between AAC 320 vs Flac Via an ABX test online Using my IBasso DX120 and FLC 8s IEM’s.

http://abx.digitalfeed.net/

At any rate, this test is done with AAC 320, i really wish this was done with AAC 256 like Apple Music streams.

Am i going to hear a difference when moving back to AAC 256 if i couldn’t hear a difference between AAC 320 and FLAC?
 
Jan 23, 2023 at 7:12 PM Post #2 of 22

PurpleAngel

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If it's a quality made AAC256, I doubt there would be a noticeable difference.
 
Jan 24, 2023 at 3:47 AM Post #4 of 22

71 dB

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Audible differences is one thingh. Whether the differences matter is another. There is no perfect sound, because headphones/speakers are far from perfect, so how much does it MATTER that AAC256 might be audibly different from AAC320? Do you suddenly stop enjoying music between those bitrates? If you think only the BEST is good enough then yes, you MUST use the highest bitrates and best headphones in the World. Nothing less can ever be enjoyable, because your mental processes ruin things for you, but if you admit to yourself, that less can still be very enjoyable, you can... well you know what... just enjoy music and stop worrying about the difference betweem bitrates. Twenty years ago people listened to 128 kbps mp3s. AAC256 is insanely transparent compared to that.
 
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Jan 24, 2023 at 12:25 PM Post #6 of 22

71 dB

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Can't you encode a file or two in a few bitrates and use foo_abx to check for yourself?
Too much trouble and Siri didn't give a satisfactory answer. The only option left is to come here and ask.
 
Jan 24, 2023 at 2:21 PM Post #7 of 22

bigshot

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I did a well over a week of testing different codecs and data rates before arriving on a setting for my media library. I determined that AAC192 is good enough for almost all recordings. But I found one particularly difficult to encode track that artifacted slightly at that rate. At 256 is was totally gone. So I decided to use AAC 256 VBR as my standard setting. I've had no problems with that after thousands of encodes. I always check the box for verifying the rip.

The difference in file size between AAC 256 and 320 is negligible, so either one you want to use is fine. But do always use VBR. It can only help and can't possibly hurt.

For the purposes of listening to music, transparency is ALL that matters. Your ears are what you're feeding. If you have OCD, nothing is going to be good enough though. Audiophiles make crazy illogical decisions for all the wrong reasons all the time. It's perfectly possible and practical to expect audible transparency from lossy. Just use a setting that gives you that and move forward and don't look back.
 
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Jan 24, 2023 at 10:12 PM Post #8 of 22

WoodyLuvr

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I determined that AAC192 is good enough for almost all recordings. But I found one particularly difficult to encode track that artifacted slightly at that rate. At 256 is was totally gone. So I decided to use AAC 256 VBR as my standard setting. I've had no problems with that after thousands of encodes. I always check the box for verifying the rip.
Concur, I too have experienced this "artifact event" when ripping a very few older monaural recordings from 1940/50s or earlier. When it happens I usually detect a minor garbling effect occurring in background instrumentation and vocals only. Not sure exactly why this happens with only but a few recordings though but it is totally fixed with the slightly higher data rate as mentioned.
 
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Jan 24, 2023 at 11:36 PM Post #9 of 22

bigshot

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The one I hit was a mono recording from the early fifties with some really unique sounding massed strings.
 
Jan 25, 2023 at 5:51 AM Post #10 of 22

71 dB

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But do always use VBR. It can only help and can't possibly hurt.
Actually at least in the past some audio products where not able to play VBR files correctly and there was artifacting due to that. I suffered from such problems. So, I used CBR only, but I think this problem has since "gone totally away."
 
Jan 25, 2023 at 6:31 AM Post #11 of 22

71 dB

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Concur, I too have experienced this "artifact event" when ripping a very few older monaural recordings from 1940/50s or earlier. When it happens I usually detect a minor garbling effect occurring in background instrumentation and vocals only. Not sure exactly why this happens with only but a few recordings though but it is totally fixed with the slightly higher data rate as mentioned.
Interesting. I am not myself big on old monaural recordings and I don't have experience on encoding them. Maybe the encoding algorithm sees that the channel difference is zero and maybe the high frequencies roll off in a way that makes it confused? Some time ago I wrote a Nyquist plugin that processes a (double) mono track creating random delay differences between the channels (kind of random Haas effect). The end result is "diffuse mono", that "feels" stereophonic on headphones, but all sounds are located in the middle. It doesn't create left-right-information (which would locate instruments left to right), but it removes the "dead flatness" from monophonic sound on headphones (when even the room acoustics do not generate differences for left and right ears). It may look stupid to add a random Haas-type effect on a (double) mono track, but imho it works (when the parameters are correct), because monophonic sound on headphones is imo very lifeless and as unnatural as excessive stereophony. The nice thing with this processing is that it doesn't add colourization to the sound. Both ears still hear the "original" mono sound, but just delayed randomly. The signals get mixed in our brain as spatial information.

Anyway, I wonder if this kind of diffuse mono processing would help with this problem?
 
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Jan 25, 2023 at 7:36 AM Post #12 of 22

bigshot

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It isn’t a frequency issue, it’s gurgling artifacts. I think it’s due to euphonic distortion that doesn’t look to the algorithm like music. It’s similar to the artifacting in crowds applauding. It’s a sound the codec wasn’t designed to handle.
 
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Jan 25, 2023 at 10:09 AM Post #13 of 22

71 dB

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It isn’t a frequency issue, it’s gurgling artifacts. I think it’s due to euphonic distortion that doesn’t look to the algorithm like music. It’s similar to the artifacting in crowds applauding. It’s a sound the codec wasn’t designed to handle.
I don't know what you are answering because you don't quote. Mono or VBR?
 
Jan 25, 2023 at 10:45 AM Post #14 of 22

bigshot

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“Maybe the encoding algorithm sees that the channel difference is zero and maybe the high frequencies roll off in a way that makes it confused?”
 
Jan 25, 2023 at 12:54 PM Post #15 of 22

71 dB

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“Maybe the encoding algorithm sees that the channel difference is zero and maybe the high frequencies roll off in a way that makes it confused?”
So why does gurgling artifacts happen only with mono sound? Lossy audio formats encode channel difference separately (joint stereo) unless told to encode the channels separately.
 

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