Whenever I teach, I always ask the student what kind of music they listen to. If they're into rock I will take a different approach than if they were into jazz. The problem with music theory is that it's a huge subject. It's too big to tackle for most people. There are so many facets to theory that it's hard to even apply it to your music. That's why I find out what style of music they're into and apply the theory to that. There are things that are done over and over in rock music that can easiily be taught and explained. There are other things in music theory that happen in other genres that are interesting but don't apply to rock music.
Most of us start off with learning some scales. Usually you'll try to learn a couple, see how fast you can play them, and it'll end at that. Learning scales is just the first step. You must learn how they apply. You must learn how they apply to rock. Although it doesn't sound like it, rock uses the same basic scales that all other popular music does. First of all, the melody that the singer is singing is a scale. Rock doesn't go too far with this. It's either major, minor or pentatonic. It doesn't sound like a scale to us because we're used to hearing scales played up and down literally. Most (not all) rock melodies are quite simple and don't jump aroung much. Most of the time a single note is repeated before going on to another. There is also tons of inflections, slides and bends that we naturally do when we sing. Scales really come into play when we study guitar solos. Most of the time the guitar player will use one scale to solo over the entire song.
Chords follow the same general direction as scales. Rock music usually try to keep things simple. They will change chords on a regular basis throughout the song. Once they establish a rhythm pattern, they will usually stick quite close to it. Most rock music will rarely go beyond the major and minor chords. Rock likes to use added 2nds, 4ths and 6ths along with a few dominant 7th chords. Most of the time they love to use power chords (which is just a 5th i.e. no third). You'll also find that different styles will use the same chord progressions over and over. Rock loves using blues progressions and progressions based on the minor scale. Some metal goes into modes and other territory but rock and pop will usually stick to diatonic chord progressions. The ubiquitous IV-V-I is still as popular as ever.
At this point you may be asking yourself so what? Well getting to know some of these tools will help in the creative process and make learning songs a lot easier. The fact is that most rock musicians know theory. They just don't have the technical terms for what they're doing. They learn things by trail and error (not always a bad thing) and then go about applying to their music. All of their theory comes in slowly from learning songs, solos, and some basic theory (usually passed on from another musician or band member).
Here is a starter list of things your should be practicing and going over on a regular basis along with new tunes and songs from your band.
- Major, minor and pentatonic scales in all keys. Rock musicians will use the pentatonic to improvise and create solos and licks. The same goes from the major and minor scales. You must learn which scale to use and when. Classic rock uses pentatonics, punk will usually stick to the major. Most of the time it's a matter of figuring out which one applies to the song you're working on and using that.
- All major and minor chords in various positions and inversions. Just knowing one or two may be enough for rock but learning these will take your playing to a whole new level. If there are more than one guitar players or a guitar and keyboard in your band you will end using these trying to make your parts work together better. If one guitar player is playing the chords in one position, the other should be playing them somewhere else on the neck.
- Chord extensions and substitutions. This is an extension of the previous but takes it one step further. Sometimes just playing a C chord is perfect for the song. Sometimes adding an extension (a 2nd, 4th, 6th or 7th) may make it infinitely more interesting. There are also chord substitutions to consider; is a C the right chord here or is a Am or Em better? Substitutions come in handy when developing ideas within a song.
- The scales harmonized in 6ths and 3rds. Rock uses 6ths and 3rds to embellish a melody and create an interesting background for songs. All scales can be harmonized this way; including the pentatonic. These are also used in creating background harmonies for the lead vocal. There are other intervals but these are the first you should learn.
- Chord progressions in various keys. Often rock and pop will stick to chord progressions within a certain key. It's important to learn all of the chords within each key. You'll notice that once you've done this, you've covered thousands of progessions and songs. These are used over and over. The key of C is given as an example:
C: I ii iii IV V vi (bVII)
C Dm Em F G Am (Bb)
Counterpoint, Voice Leading etc.
Most rock musicians will attest not knowing what counterpoint and voice leading is let alone the fact that they may be incorporating it into their songs. Voice leading is simply moving the different voices in a chord in the smoothest manner possible. Most of the time rock music flies right in the face of this and will move all over the place. Counterpoint is just having two separate lines moving independent from one another. Rock music uses these in various ways. Voice leading is used a lot in playing arpeggios and creating interesting progressions under the lead vocal. It's also used a lot in leads were the guitarists will play ascending and descending lines and arpeggios connecting them seamlessly together (the solo to 'Hotel California is a great example of this). Other times rock musicians will play a melody or line with the vocal instead of strumming chords. Other techniques rock uses are: modulation, pedal tones, vamps, polyrhythms, polychords and modal harmony (to name a few).
It's All There
If you're reading this and wondering what half of this stuff is, if you're wondering if you actually do any of this, then you know you have some homework to do. Without getting a degree in music theory it's a good idea to knnow what some of these tools are how and you can use them in your music. You may be using most of them already and not know it. Giving a name and explaination of these techniques allow you to isolate the various tools and use them in new and interesting ways. Most of all, your other band mates may be wondering where you've come up with all of these great new ideas. Don't tell them you learned some theory though, you may end up being 'the theory guy' in the band.