Music production is something most of us take for granted. All we ever hear of a song is its finished and nearly flawless final state. There is a lot of work that is put into getting this product to sound so sonically pleasing, and it is far from just "Stick a microphone in front of it and play" followed by "Put it all together and send it off". It's time to have a basic, but comprehensive understanding of the process.
The process of recording is possibly the most straightforward part of the process to understand the basics of. It is pretty much exactly what you would expect. You use microphones or other methods such as midi keyboards to record the different sounds that are going into the music production. There are different recording styles that are typical of different forms of music.
What is MIDI? Basically it is data (set of instructions) that can be interpreted by a software instrument or synth to create sound.
Normally, each individual part on each instrument will be recorded separately and on different tracks. This means there are audio bits of all the individual instruments and parts of the song. The piano has its own track, lead vocal its own, each harmony vocal its own, as well as one for each guitar part (or banjo part if you're into that type of thing). This makes editing and mixing typically be a lot of work, but also leaves a lot of room for later changes to the song as well as major edits of the individual instrument performances.
Compositions, such as a classical piece or orchestral soundtrack are typically recorded with all the instruments recorded as a whole group recorded at once. This leaves less room for major fixes or changes in the editing and mixing stages, but also allows the performers to be conducted as they are used to (by a conductor) rather than just playing to a click track as is common for non-compositional pieces.
Editing is basically anything that alters the original performance. This involves moving small bits of takes so that everything is more "tight". So, when Jimmy's chance of hitting the snare drum on the beat is about the same chance as the Cincinnati Bengals winning a playoff game, you can shift over those snare hits so they are right on the beat. By the end of editing, the actual performances are anywhere from slightly to drastically altered. Pitch correcting of the vocals also qualifies as editing, as the basic audio that will be worked with in the mixing stage will be the pitch corrected version.
Tangent: If you're one of those anti-pitch-correcting people who make fun of pop for their use of pitch correction, I have a question. Do you like any artist who has recorded in the 21st century? You do? They used pitch correction. Also, pitch correction is not nearly as magical as you think. Pitch correction in most songs is a lot more like that girl who you never noticed didn't wear makeup until the day she did, and you thought "Hmm, she seems slightly prettier today" than it is like the girl who you last saw years ago when she ate nothing but bacon and rolled in mud daily, and now she has spent years running, weight lifting and having plastic surgery to make her face resemble less Michael Jackson, more Jennifer Lawrence.
Overall, editing tends to center on tempo, timing and pitch of a performance.
Mixing is basically working with individual tracks and instruments separately to make them work together ideally. Here are some of the main parts:
Setting Levels- Setting the volumes of each individual instrument track.
Compression- This reduces the amount of variety in volume. For example, a track for which the singer starts really soft and then gets really loud has very little difference in actual volume compared to the original recorded sound due to the use of compression.
Equalization (EQ)- Adding and cutting different frequencies from a track in order to make the track fit its role and place in the song and sound ideal in context of the rest of the song. EQ is also used to sound-shape to accent the good parts of a track and attempt to make the less desirable parts less noticeable.
Example 1: A bass guitar is obviously meant to fill out the bass of the track, not the upper frequencies, so the bass frequencies will likely receive a bit of a boost, and the higher frequencies may be cut a bit.
Example 2: If a singer is too nasal-sounding, the mixer will likely find the frequencies where the nasality seems to come from the most and cut them a bit to make the sound more pleasant.
Panning- Setting where out of the speakers the sound comes from. Panned center means that the sound will play equally on both speakers in a set of two, whereas pan 100% Left would mean only the left speaker plays the instrument. This, like EQ, is meant to give each instrument its own space so that all the parts of the song can work well together.
Example: Lead vocals, kick and snare drums and bass are almost always panned center, and guitars are usually hard left and right (100% left and 100% right), with other instruments like acoustic guitars or pianos likely somewhere in between. These often vary some from mix to mix and musical style to musical style.
Effects- There are so many. Some examples would be reverb, which gives the illusion of the instrument being in a larger room, and Delay, which plays the sound on the track again after the set delay time.
Mastering is working on the entire mix as just one track. Mixing is making all the pieces fit together, and mastering is taking that put-together package and putting a metaphorical bow on it. Mixing involved equalizing and compressing each of the individual tracks to work together, and mastering involves equalizing, compression and limiting in order to make each song sound as ideal as possible as a whole. Mastering also is used to maintain flow and a consistent sound across an entire album.
What is limiting? Think compression, but setting an exact volume which the song can never get louder than.
So now you understand the process by which you get to hear that awesome new song your favorite band just came out with. It wasn't a short process and it certainly requires more than just the musicians to make the product great.