Improving MP3 quality - is that possible?
If you want to improve the quality of MP3s, it is not enough to convert them to another format. Only with complicated restoration can some artifacts of MP3s be reduced somewhat. In this practical tip we explain why the quality of MP3 files can hardly be improved and give you an introduction to the basics of audio restoration.
Why is MP3 quality improvement difficult?
MP3 is an effective implementation of psychoacoustic findings from the 1960s: Loud tones can mask quieter tones, i.e. mask them, if they are contained in the sound signal at the same time, shortly before or shortly after. Low frequencies in particular can mask higher frequencies. MP3 detects masked spectral components and stores them with less accuracy. This loss of accuracy is irreversible:
- Converting WAV or AIFF to MP3 creates artifacts because MP3 is a lossy codec.
- In some practical tips, we explain in detail what MP3 is and what distinguishes it from audio CD and FLAC.
- MP3 stores the dynamics of some frequencies with low accuracy. In addition, noise can arise from loud events.
- These errors should be masked, i.e. inaudible. If they are not, they will unfortunately not disappear if you save the MP3 with a higher bit rate or convert it to WAV.
- If good MP3 quality is important to you, pay attention to the ideal settings in the MP3 encoder and the most suitable sample rate.
- It is particularly serious if you want to convert a mono file back to stereo. In this case, you must guess the stereo information of each frequency at all times. A practically impossible task.
- If you do not want to sacrifice quality at all, choose FLAC or ALAC.
This is how you can improve the MP3 quality
If you still have the original file, you should recode the MP3 according to the instructions linked above. Otherwise you have the following options to improve bad MP3 sounds:
- In most audio players, you can use the equalizer to re-weight the frequency spectrum according to your needs. We show you in a practical tip how to optimally adjust an equalizer.
- For many people, louder means a little bit better. If you use a compressor or even a multi-band compressor, you can significantly increase the perceived volume of your music.
- For example, you can apply both effects in Foobar with a plug-in called "Effect DSP".
- With the help of our practical tips, you can remove network hum and eliminate noise and restore generally bad sound in Audacity, which you can get for free on CHIP.
- We also offer you a comfortable entry into Audacity.
If you want to have small file sizes with good sound quality, you are well advised to use the AAC format, because AAC sounds better than an MP3 of the same size.