Mixing and Mastering
In a multi track project, such as the present Christmas album, the individual performers play their parts one at a time. This is necessary when it is otherwise impossible to assemble the whole troupe to record together in the same room at the same time.
For this album, musicians were recorded in studios in Boston, Knoxville, Asheville, Tryon, and Wantage (U.K.). They wear headphones while performing so they can hear what has been recorded previously. Typically, the producer asks players to perform at least 5 or 6 takes, sometimes numbering as many as 25 to 30 takes. Each take (performance) is stored in a library of digital audio files for later consideration.
When all of the recordings from each musician have been catalogued, the mix phase begins. Each of the several hundred individual recordings is evaluated, with consideration for accuracy, musical emotion, and how well it fits together with the instruments. It is often desirable to edit performances by splicing together sections from multiple takes to make one performance that works well with the other tracks.
Mixing continues with adjusting the volumes of each instrument throughout the song to make sure that the most important melodies can be heard easily. Sound filters are applied to each instrument to produce the smoothest possible tone. Finally, reverberation is added to replicate the sound of performing in a large concert hall, castle, or other ambient environment, thus giving the music a pleasant and beautiful atmosphere.
This is a typical view of the editing software used for mixing audio. In the center you can see audio wave forms of the different instruments, and on the right are various sound filters and loudness adjusters.
Once the mixes have been finalized, the digital audio files are then passed to the mastering phase. To understand what mastering does to the music, imagine a photograph as it is originally shot. One can see the subjects just fine, but the image is usually flat and rather dull. By applying photo filters and other digital techniques, the richness of color can be enhanced and the subjects can be made to stand out more. Often the best photo editors are not necessarily photographers themselves, but rather specialists in this type of work.
Similarly, audio mastering is a separate specialty. The masterer applies high level audio filters to the music to enhance the richness and clarity of the music. Considerations are made for how the music will sound when played on the radio, when heard in cheap ear buds, on a phone, or on an expensive home stereo. Codes are further embedded into the digital audio files which include bar codes, track names, and other marketing info. The amount of silence between songs is finally decided.
This is a typical studio where mastering is done
When the final master is finished, a single, 60-minute digital file is sent to the pressing house to create CDs and to disseminate to digital online platforms such as iTunes and Pandora.