When mixing the mix engineer has many things to think about. Not only is this when you are bringing levels up and getting the volume relationship between instruments balanced, but you’re balancing the frequency response and placement within the stereo field. Then add effects and reverbs to create spacial relationships. It’s quite the dance in bringing all these elements together. This is really where the creative side begins. Like a painter, the mix engineer can really pull out the tricks and start painting that masterpiece. This auditory canvas is where the mix engineer shines and brings to life the musical vision. But, that canvas has a defined area to work within and part of the art of mixing is making everything coexist within that defined space.
The human ear only hears from 20Hz to 20KHz. And this is mostly when you’re just born and in the first few years of life. Over time these lower and higher frequencies become harder to hear as a result of normal wear and tear of daily life and high decibal levels we’re all exposed to. This reduces the defined frequency space we have to work with. All instruments from voice to guitars to bass to percussion and anything that makes a sound has a frequency space it consumes. The trick in mixing these sounds together with clarity is one of the keys to a great mix – making everything fit within this defined frequency range and within their own space. Many instruments overlap or have harmonics that affect each other. Dip a little here, add a little there can dramatically change the relationship between two instruments. Finding that balance and carving out space for each instrument so everyone has clarity is one of the main goals for a mix engineer to achieve. In addition to creating frequency space you must create a spacial relationship within the stereo field. This is where panning instruments left to right, using reverbs and delays to create depth all come into play. These aspects must be balanced as well. Creating a great mix with dimensionality is a trick in itself and one that many mix engineers struggle with. Ultimately finding balance within these areas and then balance as a whole, while adding a creative flare through effects, dynamics and musical arrangement, is what makes a mix great. Once the mix engineer achieves that balance and produces a mix that translates the vision of the song it becomes time for the audio mastering process to begin.
Audio Mastering is where the mastering engineer takes the final mixes and puts that final polish on them. This is where, in many respects, the mixes go from sounding like mixes to sounding like masters on a record. By bringing balance and clarity through equalization and compression, the mastering engineer enhances and makes the listening experience more consistent across varying playback devices. The mastering engineer listens as a whole versus the sum of all the parts. By applying final equalization to balance and enhance we give the tonal response consistency and through creative compression and limiting we create volume and dynamics consistency. The end result is an effort to make the musical experience a pleasurable one and also allow the music to translate consistently in varying playback environments.