Most of the people, at least indirectly related to sound, at some time are faced with converting audio to a more compact format for storing or playing a track on mobile devices.
MP3 is very convenient for this, but this is what they call the “lost” format. This is due to the fact that compressing the file – there is a loss of frequencies in the entire spectrum of the recording. You may not notice this while listening to low quality technique, but the changes are quite significant.
For fun, we did some research. As the source, they used a few seconds of the violin CD Sophie Matter playing part of Mozart’s violin concert. This passage was chosen due to the fact that its harmonic content sometimes exceeds 20 kHz, and the game is accompanied by a full classical orchestra. It was copied with standard properties: bit rate 1411 kbit / s, 44 kHz, 16 bit stereo. The spectral frequency analyzer CoolEdit was used for display.
We made several mp3 versions of the sample in different quality, using the SUPER eRightSoft converter.
Here are some of the results (bitrate -> frequency compression):
- 1411 kbps> 20 kHz 1: 1
- 320 kbps> 19.5 kHz 1: 4.4
- 192 kbps> 18 kHz 1: 7.3
- 160 kbps> 17 kHz 1: 8.8
- 128 kbps> 16 kHz 1:11
- 96 kbps> 15 kHz 1: 14.7
- 64 kbps> 11 kHz 1:22
- 32 kbps> 5 kHz 1:44
To notice a significant difference, you need to have a good ear and absolutely modern studio equipment. When you get 128 kbps (the quality used on CDs, as well as streaming services), even in old headphones you can hear compression distortions.
When you convert to mp3 format, not only high frequencies are cut (although the upper difference of 16 or 17 kHz is not significant for most adults), but also the compression of everyone else. Of course, it’s not always possible to listen to audio in uncompressed wav or flac, given their size (from 40-50 mb per file), but when converting sound to mp3, keep in mind that its quality will not improve, but will intentionally deteriorate. To get less distortion, avoid dropping to 192kbps or lower. When recording sound to mobile devices, set the recording to wav format, and then make changes and editing additionally.
If difficulties arise, our studio offers restoration of sound, as well as supplementing the track with tags to display the cover and authorship during playback.