Mastering ( also audio mastering ) is the ( artistic) completions of sound recordings and the final step in music production before creating the audio medium.
Concept and definition
This meant mastering here should not be confused with the last preparatory stage of production before the actual pressing process, which is also referred to as ( technical ) mastering and includes the creation of the master ( glass master for CD and template in vinyl records pressing).
When audio mastering is in front of it steps in post-production and editing of sound or data material and the final creation of a " pre-master CD" ( pre-mastering ) or DDP ( Disc Description Protocol) Masters, for as a positive template serve the creation of the master in the pressing plant.
As has prevailed for audio mastering typically the short term mastering, the delimitation is to be explained again at the steps of an exemplary today's CD production:
In steps 1 to 3 are steps of music production. Step 4 is finally also carried out usually by a mastering engineer.
Objective and detailed steps
Objectives of mastering are there to give the present a better quality audio material and to allow the playback compatibility on as many devices and media. A professional sound recording should also sound good when played on a small stereo system such as in the broadcast on the radio or listening through headphones. Both a balanced stereo image, a good mono compatibility and a smooth frequency response play a major role. During the mastering process, these factors are more accurate lit and, if necessary, corrected.
One mastering require not only new but often old recordings, which require for their quality before re- publication of a sonic improvement either, especially from analog master tapes ), or for other publications in a new compilation. One then speaks of remixing ( " remastering " )
In addition to the purely technical processing can be achieved by mastering often a significant improvement in the sonic impression of a music / sound production. For this purpose, various technical equipment - such as filters, equalizers, compressors and psychoacoustic devices - are used.
Even when mastering, the stereo width can be changed. This is achieved by a technique known as MS- mastering, the signal is separated into mid and side signal. This allows level adjustments of instruments that are located in the Panorama center, perform in relation to the panned after further out instruments.
The mastering may include, depending on the request by the source material, among others, the denoising, the signal level and pause harmonization of the individual securities or the removal of digital jitter and the creation of panels ( engl. fades ).
After the actual audio mastering the song order are the pre-mastering, takes place at the usually no more sound processing, determined, set breaks and track indices and applied certain additional information, such as ISRC, EAN codes or CD Text. Finally, a pre-master CD is created, which should correspond to the Red Book standard for audio CDs. Before the time of the hard disk Recordings and exclusively as vinyl records were produced, these steps accordingly fell away or were only carried out by the pressing plant. Then a master tape was created in conclusion, which served as a template for production of sound recordings in the press shop.
Digital and analogue mastering
A distinction is made between digital and analog mastering. With the digital mastering processing is usually done completely with computer technology and special audio software (so-called digital audio workstations ). All necessary, known from conventional analog technology devices are available here as a virtual machine in the form of so-called plugins available. This method is the cheapest, but is subject to certain limitations, especially in terms of real-time capability, which will be due to the system never achieved completely even with the most powerful hardware, because some plugins cause a delay of the signal. Therefore, in pro studios preferred external DSP-based studio equipment will be integrated into the signal path, in which the signal processing in a similar manner purely mathematical - but perfectly real - time runs out.
In the analog mastering mastering engineer, however, the recourse to conventional analog equipment that are integrated with high-quality AD converter, called Studio converter in the digital setup today's studios. By using real analog devices bypasses to the partially existing artifacts of digital editing: one hand, the mathematical models used the analog components not any exact from, on the other hand always ask the algorithms a compromise between execution speed and accuracy dar. Sonically are the digital processors their analog models but in nothing. The digital reproductions of the analog devices also have the advantage that the analog sound of the original hardware can be switched on and off at will. The principal disadvantage of analog technology towards digital technology - namely, the clay material inadvertently add distortion and noise - turns on high-quality equipment, although only little problem is, but can also be used intentionally to give the audio a characteristic sound. This mixed mode of operation, also called hybrid technology, is the most expensive.
Due to the increasing power of computer technology and digital stand-alone hardware is now slightly on the decline, especially since not a few manufacturers offer their software in both devices as well as inexpensive plugins. The plugins are in many cases at an advantage: When offline computing the software they provide precisely because of the lack of real-time constraints, a mathematically more precise result.
Besides classical recording studios with their engineers there are special mastering studios where mastering engineers are concerned exclusively with the sonic improvement and harmonization of foreign recordings. Often, however, the desire of the customer is also satisfied by the production of a loud final product, which can be done only under severe reduction of the dynamics and transparency of the audio. Was to see the resulting problems loudness.