Stereo systems. Page 3

Dynamics and mastering

Mastering has become the latest "thing" to make your recordings sound better. Usually it involves two alterations of the sound: a compression and a change of the frequency response. To take away the dynamics of the music makes it more listenable in bad acoustic conditions, such as in a car or at discotheques. However, if you have qualified stereo equipment, this mastering-technique will be seen as making the recorded sound lifeless and flat. Most people do not have good equipment at home and, from what I've seen, haven't set them up properly. Therefore, if you want to sell many CDs, mastered sound is, by far, something that most people will prefer. For the true audiophile it's another matter altogether... If you belong to the HiFi group that believes that transparency of the sound is the right way to go, mastering becomes defined as a way of distorting the recording. In fact, all good recordings should not have to be mastered at all.  

When I "re-master" recordings which were poorly recorded in the first place to make them more listenable I use only 1,5 dB as a limit for the frequency response. This is very little. Considering that most people have loudspeakers that feature as much or worse frequency response, they will hear only a small difference between the before and after mastering efforts. But a good recording should not have to be mastered at all. Changing the frequency response too much will introduce time-faults in the sound. But most importantly; any EQ will also change the frequency curve of the direct sound to something very uneven. Be careful to not over-use and overdo your EQ!

A good system will have very good dynamic ability. Even though limiting of dynamics is what is usually done in a mastering situation, a speaker that does not have a strong dynamic capability will not portray the sound correctly. The speaker must work at only a fraction of its capability to be able to deliver a true representation of the recorded sound, i.e. with low distortion. 



The recorded room

It is important to mention that the speakers must be able to deliver a true representation of the recorded room. This is a very difficult thing to do for a stereo system. One that really separate the bad systems from the truly great ones. You also need good recordings to be able to judge the qualities of your system. More on that in the recording section. Worth mentioning is that in Mp3 encoding, room information is usually considered unimportant and is partially removed from the recording, especially at the lower bit rates. If you use 256 kbit/s, it will be difficult to actually hear the removal, but at 192 kbit/s or lower, its absence is very clear and easy to hear. The newer "Ogg coding", seems to be much more effective at lower bit rates.

Regarding the new digital radio system, DAB-radio. The planned transfer rate in Sweden is going to be only 128 kbit/s. At that rate, the distortion of the sound as well as the lack of a true representation of the recorded room will be very obvious even to the untrained listener. In fact, given these premises, the new digital radio broadcasts sound quality that is inferior to the "old" analogue radio! Isn't it natural to expect an improvement when a new system replaces an old system?

News from December 2005, the Cultural Minister announced that after 10 years of experimenting with the DAB-radio system, further development will be terminated. A lot of time and money has been wasted. Clearly, in my opinion, a new system must be of higher quality otherwise it's of little value. But in this case, quality has not been a priority. The primary aim in the development of digital radio seems to have been the delivery of more channels. I do think that with newer bit reducing systems like the Ogg Vorbis format, a digital system can both be of high quality and offer numerous channels. Maybe the last word has not yet been spoken ...

Well, in 2010 as it's now, we still have digital radio ... But, one cannot say that there is a lot of radios available in shops or the system has gained in the market. We will see what happens with the system in the future. 

A lot of people are today using direct streaming sound over the Internet, and play back the sound with the help of computers or even telephones. This is of course a sound quality that is very much inferior to the sound that is possible over the CD medium. But, at the same time, the mastering race over these last years has accelerated even further, and more and more CD's are released with very little available dynamics (with a crest-factor of only 4-6 dB). With such a low quality compressed sound marketed on CD's, it makes little difference to the quality of the sound, if the sound is further compressed over the air ...



More information on these topics can be found on the acoustic pages, the concentrated listening pages and, obviously, on the recording pages.


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