Sorry FearTheMateria for stealing this 
But I have a lot of vested interest in this type of topic being a 30 years+ and published musician...
Lets have an example: Beethoven's "Ode to Joy" - Symphony No. 9 in D minor, Op. 125 "Choral"
Just about everyone with working ears has heard this extremely simplistic (and yet strangely attractive) melody, but in case you are unfamiliar: -source
Now why do I note it's "strangely attractive?" What IS it about this song, or other songs, that just... sound right? Why is that when you hear a specific sound, your brain seems to know which one "should" follow... that when you hear the wrong note following, you wince at it?
These questions are at the heart of Music Theory. It attempts to answer these questions, by breaking down music, especially of past eras such as Baroque, Classical and Romantic, and providing a language by which one can assess a piece of music, and understand it.
Now, a theme like the one in Ode to Joy, though able to be played by most first year music students, still employs "rules" of Music Theory. The notes that are played, are in a "logical" order... the music takes a shape, and is "correct" ... none of it sounds wrong, as if a note were missing, or "off key."
There are many fundamental principles in Music Theory that go a long way to explain why music ... works. Why it sounds right. Things like, the "relative minor." Its interesting the mathematics behind this one principle, but in essence every "Major" scale has a relative "minor" scale, in which the "notes" in each scale are identical, and yet when played back to back, have very different "moods." Why, even the concept of "Major" vs "minor" requires quite a bit of study. Here's an excellent resource for anyone interested: Tonal Harmony a textbook on Music Theory you may find in your local library and through this link for purchase. It's a must-have for anyone serious about learning Music Theory.
Now that we've established -what- Music Theory is, why its important... we now move on to Improvisation.
Improvisation, is at its core, everything that Music Theory employs, without employing it! Example, Ode to Joy. Yes, Music Theory can be used to disect the song, and yes the song fits the mold well, its tones and measures are identifiable, its structure sound. But why did Beethoven choose the EXACT notes he did. His chord progression makes sense, in Music Theory terms, but the notes themselves, which make up the "melody" ... that was him. All him. He improvised that melody from his very soul, it came to him like all melodies come to all musicians that write them. There's no ... mathematical equation to create that melody, no Music Theory to explain it, only to explain why it works.
This is key in understanding how good music is written vs bad music. Yes, Music Appreciation is highly subjective, but you'll notice that you can hear a piece that will make you cringe, the veritable lemon to your ears, vs a nice melody, one that makes you go "ah, that's nice." Maybe it's Slayer, lol "ah, that's nice." But it's nice, and you like it. Why? Because it's honest... it can be applied to Music Theory and deconstructed thus, but ultimately it is rooted in creation from thin air, from the mind outward, and this gap... this "where did it come from" is at the heart of Improvisation.
Music Theorists often attempt to write original music employing the rules of Music Theory without employing any Improvisation. The result? Sounds terrible, usually, lol. Because there's no... soul behind it. It's just math. A computer program can even write its own music with enough variables programmed in. Will it sound right? Hit or miss really, it -can- write something that sounds good, but it's by chance. A human on the other hand, commands the music. The musician brings from within and displays outward the "next note" to the previous one, and it falls in line, a string of sounds that not only sound right, but sound good. Even Great if you're a great composer. Soloist. Improv artist. I won't say great musician, because often times you will find many musicians who are excellent at copying what someone else has written, and they can even give it their own feeling, their own "take" if you will, but they still can't come up with anything original on their own. This fundamental difference is at the heart of Improvisation, as it continues to elude many people to this day.
So this begs the question, which is more important to learn? Theory? or Improv? Well, the answer is simple. You LEARN theory, you DEVELOP improvisation. You cannot attack both the same way, and hope to get results. When it comes to Theory, it's as much learned as is Geometry or Algebra. When it comes to Improv, it takes as much practice as painting, or writing a poem. Some will get it right away, or will be seemingly "born" to improv, others will painstakingly practice for years, never quite getting the knack of it. How is this possible? Well my own personal view on this is that some folks have the improv switch turned on in their brains, others do not, and no amount of forcing the switch on will work. But this is just me.
How does this relate to Popular Music? Well, unfortunately, the lines have blurred over the years, the quality of musician has lessened, the Pop-music genre has been dumbed down from its roots ... but there's no mistaking a great melody, the kind that sticks in your head. And so long as people exist, so too will music and its ability to enthrall.
But I have a lot of vested interest in this type of topic being a 30 years+ and published musician...Music Theory at its core, is a way of understanding the fundamental relationships in and organization of sound.
Lets have an example: Beethoven's "Ode to Joy" - Symphony No. 9 in D minor, Op. 125 "Choral"
Just about everyone with working ears has heard this extremely simplistic (and yet strangely attractive) melody, but in case you are unfamiliar: -source
Now why do I note it's "strangely attractive?" What IS it about this song, or other songs, that just... sound right? Why is that when you hear a specific sound, your brain seems to know which one "should" follow... that when you hear the wrong note following, you wince at it?
These questions are at the heart of Music Theory. It attempts to answer these questions, by breaking down music, especially of past eras such as Baroque, Classical and Romantic, and providing a language by which one can assess a piece of music, and understand it.
Now, a theme like the one in Ode to Joy, though able to be played by most first year music students, still employs "rules" of Music Theory. The notes that are played, are in a "logical" order... the music takes a shape, and is "correct" ... none of it sounds wrong, as if a note were missing, or "off key."
There are many fundamental principles in Music Theory that go a long way to explain why music ... works. Why it sounds right. Things like, the "relative minor." Its interesting the mathematics behind this one principle, but in essence every "Major" scale has a relative "minor" scale, in which the "notes" in each scale are identical, and yet when played back to back, have very different "moods." Why, even the concept of "Major" vs "minor" requires quite a bit of study. Here's an excellent resource for anyone interested: Tonal Harmony a textbook on Music Theory you may find in your local library and through this link for purchase. It's a must-have for anyone serious about learning Music Theory.
Now that we've established -what- Music Theory is, why its important... we now move on to Improvisation.
Improvisation, is at its core, everything that Music Theory employs, without employing it! Example, Ode to Joy. Yes, Music Theory can be used to disect the song, and yes the song fits the mold well, its tones and measures are identifiable, its structure sound. But why did Beethoven choose the EXACT notes he did. His chord progression makes sense, in Music Theory terms, but the notes themselves, which make up the "melody" ... that was him. All him. He improvised that melody from his very soul, it came to him like all melodies come to all musicians that write them. There's no ... mathematical equation to create that melody, no Music Theory to explain it, only to explain why it works.
This is key in understanding how good music is written vs bad music. Yes, Music Appreciation is highly subjective, but you'll notice that you can hear a piece that will make you cringe, the veritable lemon to your ears, vs a nice melody, one that makes you go "ah, that's nice." Maybe it's Slayer, lol "ah, that's nice." But it's nice, and you like it. Why? Because it's honest... it can be applied to Music Theory and deconstructed thus, but ultimately it is rooted in creation from thin air, from the mind outward, and this gap... this "where did it come from" is at the heart of Improvisation.
Music Theorists often attempt to write original music employing the rules of Music Theory without employing any Improvisation. The result? Sounds terrible, usually, lol. Because there's no... soul behind it. It's just math. A computer program can even write its own music with enough variables programmed in. Will it sound right? Hit or miss really, it -can- write something that sounds good, but it's by chance. A human on the other hand, commands the music. The musician brings from within and displays outward the "next note" to the previous one, and it falls in line, a string of sounds that not only sound right, but sound good. Even Great if you're a great composer. Soloist. Improv artist. I won't say great musician, because often times you will find many musicians who are excellent at copying what someone else has written, and they can even give it their own feeling, their own "take" if you will, but they still can't come up with anything original on their own. This fundamental difference is at the heart of Improvisation, as it continues to elude many people to this day.
So this begs the question, which is more important to learn? Theory? or Improv? Well, the answer is simple. You LEARN theory, you DEVELOP improvisation. You cannot attack both the same way, and hope to get results. When it comes to Theory, it's as much learned as is Geometry or Algebra. When it comes to Improv, it takes as much practice as painting, or writing a poem. Some will get it right away, or will be seemingly "born" to improv, others will painstakingly practice for years, never quite getting the knack of it. How is this possible? Well my own personal view on this is that some folks have the improv switch turned on in their brains, others do not, and no amount of forcing the switch on will work. But this is just me.
How does this relate to Popular Music? Well, unfortunately, the lines have blurred over the years, the quality of musician has lessened, the Pop-music genre has been dumbed down from its roots ... but there's no mistaking a great melody, the kind that sticks in your head. And so long as people exist, so too will music and its ability to enthrall.
