Is AAC absolutely better than mp3?
I know that the lossless sound source is of the highest quality, but the file size is too large.
I want to hear it in the smallest possible size with the best possible sound quality!
I think there are many such people. I am the same.
This time, I would like to roughly examine the differences between mp3 and AAC.
I don’t know because it’s just a little bit snooty for a hobbyist.
Effect
Since this is a compressed sound source, casual listening is an important premise.
First, let’s abandon the stereotype that “AAC is better.”
Looking at the net, there are people who write that “AAC is better because it came out later” or “AAC is better because it is an improved version of mp3”, but the compression efficiency is good and the sound that you can really hear in particular, not I think it is always the same to improve.
This study then only confirms the “objectively understandable difference” for each format, and does not determine the superiority or inferiority of sound quality.
Personally, assuming 320 kbps, even if it is a compressed sound source, be it mp3 or AAC, the audible range is perfectly suppressed, so I think the sound you hear is the same, and I only listen casually. I don’t even have to hear the slightest difference.
Honestly, 128 kbps is fine for portable use (although the audible range changes significantly compared to 320 kbps), but if you’re looking for a premium music experience with home audio, you should use a compressed sound source first. use time.
Frequency analysis
There are many other people who do the same, but I’ll check it out myself.
Note that the vertical and horizontal widths differ for each graphic.
All encoding to mp3 / AAC is done with iTunes.
First, I prepared a FLAC sound source sample. The genre is rock.
The characteristics of 4608 kbps bit rate / 96 kHz sampling rate / 24 bit bit depth of
frequency are as follows. This is the original way.
Generally, the human audible range is said to be around 20Hz to 20kHz *, but with FLAC, you can see that information is also included in the ultra-high range above 20kHz.
* Actually, it seems that most people have a hard time distinguishing between 15 kHz and higher.
Then AAC / 320 kbps
* Sampling frequency 44.1 kHz / Bit depth 16 bit
There is information above 20 kHz, and it seems that the sound around 22 kHz is cut off by gradually attenuating. Looking only at the frequency, there is not a big change from FLAC. Is the sound pressure so low that you can’t feel it? That is all.
Then mp3 / 320 kbps
* Sampling frequency 44.1 kHz / bit depth 16 bit
It is characteristic that it cuts from around 20 kHz.
When mp3 and AAC waveforms overlap, it becomes as follows.
Purple is mp3 and pink is AAC.
There is a considerable difference in the amount of information above 18 kHz. Also, you can see that the other parts are exactly the same (there is a difference in the level of points when zoomed in, but it is considered a negligible difference).
Let’s listen and compare
It is out of the question to mention the difference in sound quality, but there is a huge difference when you look at the waveform above, so experience how it feels when you listen to it.
320kbps mp3 and 320kbps AAC were carefully compared to listen to over and over again.
As a result … well …
I did not understand anything.
There were some parts that said, “Oh … I feel something different …”, but when I did a blind test with the hidden extension, I had no confidence at all, so I decided to be a placebo.
When you play the same song randomly while walking down the street, you are unlikely to know “Oh, this is the mp3!” Or “This sharp glow … AAC!” . In my ears.
conclusion
You can convert it as you like (appropriate).
It seems certain that AAC has better compression technology, but I think it is almost impossible to distinguish the quality of the sound that is actually heard in a casual environment.
