I think that the study of music theory is actually a very interesting thing, not nearly so boring as it’s reputation seems to suggest, and the thing is, understanding music theory will definitely make you a better musician. Since you want to be good it is definitely in your interest to become very interested in music theory. Ideally, we don’t want you to try to force yourself to study music theory as if by tyrannical force as it is exhausting and can only be sustained for short periods of time, we want you to thirst for this knowledge and wonder about it when you have a spare moment. What I am going to attempt to do in this article is help you to see music theory in a way that makes your brain thirst for knowledge of music theory. This article is also designed to give the view from ten thousand feet of music theory. If you know nothing at all about music theory, this is a great place to start, but if you do know it well, I still think that this article is likely to offer a useful perspective. That perspective, generally speaking, is that the subject of music theory is really a crossing of two subjects, namely the science of pitches and vibrations, combined with the psychology of how a human mind with it’s predisposal to aural communication perceives and experiences said pitches and vibrations.
All that a guitar or a piano does is vibrate, even your favorite song is really just a very nuanced and well developed, layered and structured set of vibrations that unfold in a very specific order over time. The thing that makes a guitar or a violin a musical instrument is the fact that it is a tool that can produce a vibration at a very consistent predictable, and controllable wavelength.
When we say pitch we are referring to the rate quality of a vibration, how many times it vibrates within a given time frame. To study harmony is to seek to understand how multiple pitches sound together within a given moment of time. This is important because as it turns out, people are incredibly sensitive to the harmony between pitches. Any two pitches when sounded at the same time will exist somewhere in the spectrum from dissonance to consonance. Dissonance is when two pitches seem to grind roughly against each other, consonance is when they sound very smooth together. A chord on a guitar is a specific hand position that you can memorize, but a chord in music theory is harmonization of a given scale. The way that modern musicians use music theory is in a nutshell, at any given moment in a song there will be a current chord, which is at that moment setting the basis for the sound of the entire group. If at a specific time a group is playing a D chord, you can play any D note or any note which is consonant with the D chord that is being played by the rest of the group and it will sound smooth and good over the music, these notes consist of the notes that are actually in the chord itself (ie. currently being played by other musicians in the group at that very moment) or at least consonant with them. At any given time as well you could play any note that is Dissonant against the D chord that the band is currently playing and that note will sound rough, adding to the tension. Indeed every note one could play has a different feeling it would carry in that specific musical context, some seeming to blend easily with the song and others seeming to grind upon it. A key takeaway from this is that any specified pitch will always offer that same musical expression/listening experience when it is produced within the same musical context. This is not to say that one should only play those notes that are “within the key”, or sound smooth and consonant. Indeed there is a smoothness that can only be found at the end of a great dissonance, which is why I say that contrary to popular belief, the study of music theory is not the learning of a set of rules on how music should be made. What it really is, is the categorization of musical expressions based upon how they are experienced by the listener or the player of the song. Which is why music theory is so valuable and useful, it categorizes things based upon how we humans actually hear and experience them.
This is incredibly useful in a multitude of ways. First of all as you proceed to study music theory and apply it to your instrument it will provide a framework which will allow you to see what you haven’t explored yet. Another invaluable thing that music theory allows you to do is take a piece of music that you find moving, and analyze it to find out what is happening in that part that you like so much. Once you have dissected and understood a piece of music you will be able to take whatever expressive elements the song used and apply it to your own songs/ improvisation, you can even apply the same musical expression under different musical contexts and get what will be slightly different but still a largely familiar and related musical experience.
The best news is that it really is not that big of a subject. While it can seem a bit abstract and technical at first glance I intend to go into detail on those specific things that need to be well understood from the perspective of the working musician and make them simple to understand. The thing that really takes the time is the developing of the technique of applying these musical theory topics to the guitar. Which is why in the mean time I generally suggest that you begin learning chords and scales, and practice them daily. Even a decade from now your fluency with these simple chords and scales will still be the thing that is limiting your playing. As far as music theory goes, keep coming back and I will teach you.