MP3 CO-INVENTOR CREATES A SOUND RATING
Why CDs, SACDs, and Downloads are Ahead and FM Radio and Internet are Left Behind
Prof. Dr.-Ing. Dr. rer. nat. hc mult. Karlheinz Brandenburg, Head of the Department of Electronic Media Technology at TU Ilmenau, Director of the Fraunhofer Institute for Digital Media Technology (IDMT)
Prof. Dr.-Ing. Dr. rer. nat. hc mult. Karlheinz Brandenburg, Head of the Department of Electronic Media Technology at TU Ilmenau, Director of the Fraunhofer Institute for Digital Media Technology (IDMT) [Source: TU Ilmenau]
“We can wage a real war of faith to get the best sound quality,” says MP3 co-inventor Prof. Dr. Karlheinz Brandenburg. Together with Meinungsbarometer.info, the researcher has created an exclusive and for the first time a sound ranking of all popular music playback formats. A test with surprising results.
Which medium, which transmission path offers the best sound theoretically / physically?
Sound quality is very subjective: what is still acceptable to one ears sounds strange to others. The quality that is heard also depends on the specific piece of music that is being listened to; some processes have clear weaknesses. When digital data reduction methods are used (i.e. streaming / downloading from portals / DAB / Internet radio / DVB), there is a massive dependence on the codec used (i.e. .mp3 or AAC or Dolby Digital or FLAC .. .), but also of the bit rate used. Basically the following applies: Theoretically, there are only restrictions on the perfect subjective quality for: streaming FM, LP and variants with data reduction with too low bit rate, i.e. .mp3 (some interference for certain music material are always audible). If all done correctly, the following methods work perfectly for listening tests: CD, SACD, Download / Stream using so-called “lossless” encoding methods (for example, FLAC), and AAC at high bit rates (as in iTunes Music Shop). The differences with DTS or Dolby Digital or .mp3 at 256 or 320 kbit / s are very small. Radio via DVB-C or DVB-S is often preferable to FM radio (because dynamic compression is not used), even if you listen to the same program.
How does it look in common practice?
We can wage a real war of faith for the best sound quality. Since the brain’s expectation plays an important role (“vinyl records sound better”), the answer will vary from person to person. We can identify some “quality sinners”: dynamic compression, bit rates that are too low, especially with Internet radio, some of which sound horrible, and errors in the encoders, which can cause audible interference depending on the playback device. My personal order (good to bad) with well-made recordings and corresponding bit rates is:
1) CD (the reference) / SACD / Download (lossless codec)
2) Download (good “lossy” codec)
3) Radio via DVB / streaming (depending on bit rate)
4) DAB + / LP
5) FM / Internet radio (relatively high bit rate, good codec)
6) Internet radio (wrong bit rate for codec)
Will data reduction music formats, such as mp3, lose importance in the future as increasing amounts of data can be moved on the Internet?
I’ve known the plot since 1983, before .mp3 was invented. There are still many applications where the amount of data transferred is economically important. Also, all end devices understand .mp3 so it will survive. On the other hand, data reduction music formats are now almost non-existent in the studio and in the feed.
What music formats and platforms do you think will gain relevance in the future and which ones will lose? Are there new music formats or platforms on the horizon?
“Object-oriented” music formats have been debated for 15 years. Now there is a transition to practice with Dolby Athmos in the cinema (which is already frequently found) and the MPEG-H standard for home and broadcast applications (still under discussion in the relevant committees). These formats not only allow for greater flexibility in terms of the playback arrangement (number and placement of speakers), but also much better surround sound than previous surround systems. Many such systems already exist in the field of large-scale sound reinforcement (Bregenz Festival, planetariums, opera). All of these examples can also be found as a research focus of our Fraunhofer Institute for Digital Media Technology.
We are currently seeing efforts to improve the sound quality of Internet radio and broadcast systems. Often this is less of a codec problem and more of an operational problem. We have lived for decades with the fact that FM radio sound is significantly affected by compressors (which make stations louder).
