I was studying at an audio engineering school back then. We had mixing classes, which the teacher showed us how he was doing mixes. Even if we had many courses about mixing and the tools we used while mixing, I still didn't know what it was.
I had a classmate with whom I was talking about these kinds of things. A night after a couple of drinks, I asked, "What the hell is mixing and what do we do while we mix? Is it just equalizers and compressors, or is there something we don't know?" I asked that question again and again to myself at the beginning of every mix that I had.
After a while, I stopped asking because I knew the answer instinctively. So I want to tell you what mixing is and what we mixing engineers do to your song.
What is mixing?
First of all, mixing is an art form that is a mixture of a technical and creative process in which we blend multi-track recordings generally into one stereo channel with balance.
Every person has tastes of music, and balance is a relative thing. So there are so many possibilities about a song's mix, and every other mixing engineer will deliver a different mix because of that reason.
Let’s see what we do precisely in that process.
What do mixing engineers do?
We create a balance
If you're a user of a DAW (Digital Audio Workstation), you do that one. You can balance a song with just volume faders. It's the cornerstone of everything. We control that contrast and decide which instrument will be heard more and which will be less. We do that by determining which instrument is more critical for the song and which is just a support element.
We control panorama
We control the width of a song and decide where an instrument's location will be in the panorama. Many times we use a fundamental feature of DAWs and mixing boards, which is panning. But sometimes it's not enough. These times we use stereo imager plugins like Izotope Imager and Waves S1 to make a track wider or narrower.
We control frequencies
Everything is about frequencies in a song. We usually want to control and balance them with each other. So why do we want to do that? Because there will be unwanted frequencies like a resonance of a room or a boomy area of an acoustic guitar. Also, there will be masking within each instrument. We separate those frequencies from each other if we want to. Lastly, we add frequencies to make an instrument shine. We use equalizers while we deal with frequencies.
We control dynamics
Nobody can stay at the same volume for a whole song while recording and shouldn't be. However, if we want a song in balance and control, we have to tame these velocity changes. It's also suitable for glue wise. Generally, we use compressors for that reason, but we also do manual volume automation.
You can use a compressor for many reasons besides controlling the volume of a track. For example, we also change the transient or sustain information of an instrument. This way, we can make it more prominent or push it back in the mix.
Dynamics are not just about individual elements but also about the whole song. We control the dynamics of a song by like making verses smaller but choruses bigger. We use every tool to make that such as equalizers, compressors, faders, pans.
We control depth
We use psychoacoustic information to place instruments in depth. Sometimes we use reverbs and delays to put an instrument in an acoustic space, but sometimes we change its frequency information to put it back or take it to the front. Or sometimes it's just a volume change.
We control excitement
Last but not least, we add excitement to instruments or a song to make it unique. It's a tricky one because we can use any tool to add excitement. Sometimes it's just easy as adding frequencies, but you can sometimes do it by complicated modulation effects. Or we add harmonic distortion to add more harmonics to an instrument or a whole song. This way, you can bring upper harmonics, and it makes a song live.
We write automation
Many times a song is not static, so our mixes can't be static. We automate and change the tools parameters in different sections in our favor.
Conclusion
Sometimes a song needs to be clean and bright and sometimes dark and dirty. We give it that need with our tools. We give it a color that makes it unique. We do what needs to be done to make it best itself as mixing engineers.