AAC vs MP3: which sounds better?
AAC and MP3 are now widespread and established in both the software and hardware markets. AAC is often touted as the successor to the MP3. But is the successor really better? We'll tell you who sounds better and why.
What are AAC and MP3?
You probably know AAC and MP3 from your music downloads, audiobooks, and your audio software for ripping audio CDs or compressing WAV or AIFF files.
- Both formats are lossy audio codecs. We explain to you in a special practical tip what exactly a codec is.
- Sound in AAC format is often hidden behind the file extensions M4A and MP4.
- In a practical tip, we explain the differences between MP3 and MP4 in detail.
- MP3 and AAC are both based on psychoacoustic models of loudness and masking, which were developed in the 1960s by Eberhard Zwicker, for example.
- Although newer, more precise models exist, the innovations since MP3 have mainly been in more sophisticated signal processing.
AAC vs. MP3 - which sounds better?
AAC is newer than MP3. Does newer mean better? At least the innovations of AAC compared to MP3 have the potential for significantly stronger compression with the same sound quality or vice versa for significantly better sound quality with the same compression:
- As described above, both codecs are based on practically the same psychoacoustic models.
- However, AAC allows more flexible window sizes to respond better to transient or stationary signals depending on the signal.
- In contrast to MP3, AAC also offers more flexible windowing. If used sensibly, this can improve the frequency accuracy in the spectral analysis used.
- AAC also enables frequency-dependent joint stereo. This can save a lot of storage space with little effort, since low frequencies in audio books, music and film sound are often kept rather mono.
- Since AAC offers significantly more flexibility on the encoder side, even a good MP3 encoder cannot keep up with a good AAC encoder.
- On the other hand, an inconsiderate AAC encoder can also sound much worse than an MP3 of the same size. If you optimally encode an MP3, the result can keep up with many AAC encoders.
- In our quality comparison test of audio encoders from 2003, however, AAC wins, followed by, Warning, OGG before MP3.
- The AAC encoder from Nero also won in our audio codec test from 2005.
- AAC is also more flexible than MP3 for the user. For example, AAC supports sample rates from 8 to 96 kHz, MP3 only from 16 to 48 kHz. If you swear by music DVDs with 96 kHz, even the highest MP3 quality cannot provide you with a sufficient sample rate.
- AAC also supports up to 48 channels, MP3 only 5.1. In AAC you could theoretically encode audio material for 7.1 sound, high-order ambisonics, Dolby Atmos and Auro-3D.
- By the way, you should heed an important rule: converting from MP3 to AAC or vice versa is rather harmful for the audio quality. You should only convert for reasons of compatibility - for example, if your portable MP3 player does not support the AAC format.