All music is made up of Tension and Resolution. Without tension there would be no movement or progression and without resolution there would be no end to tension. Both are intrinsic requirements to making music satisfying and to life generally.
All Music Contains Tension and Resolution
No matter where you are at in your musical development and no matter what music you listen to you are always hearing or using tension and resolution whether aware of it or not. When the human ear hears it establishes a heirarchy of notes almost immediately. The human mind perceives and organizes pitches in a way that forms a tonal centre or key center. There are strong contributing reasons for this in acoustical physics and the harmonic overtone series and synaptic connection but those are other studies.
First, a Tonal Centre Must Be Established
When we establish that there is a strong note or tonal center or key center we then have a base point to examine the tensions of other notes against that center. All notes in a scale will be heard as varying degrees of tension against the tonic. This degree of tension could be very tense or less tense, in music we use the words Consonant and Dissonant to describe these tensions. Consonant meaning pleasing or resolved or lacking tension, Dissonant meaning tense and requiring resolution.
In fact, every note will have varying degrees of tension or sonic gravitation toward the tonic or key center. Try the following exercise. Begin by clearly playing the tonal center or key note and then proceed to the 2nd degree of the scale and really listen to what the 2nd wants to do, where does it want to go? The 2nd will in fact succumb to the pull of the tonic, if you play both the root and the second together (harmonically) this will clearly demonstrate a dissonant interval, the major second.
Continue to the 3rd again beginning on the tonic and notice that it actually has less tendency to fall. When played together with the tonic it is a consonant sound and is a part of the I chord and is thus supported by the Root.
Root to 4th, the 4th wants to fall to the 3rd especially when supported by the I as well, this 4th is referred to as suspended because it “sounds” as if it is suspended above the 3rd of the key, both melodically and harmonically.
Then to the 5th which is called the dominant and sounds like it is reinforcing the tonic, it is a strong part of the I chord and sits as a strong platform along with its root, these are the King and Queen of the key. This interval is called Perfect because of its reinforcement of the root.
The 6th is consonant and passive and will fall to the strong five which is supported by the tonic.
And finally the 7th wants to without doubt lead to the tonic and has little hope of avoiding that harmonic gravity, it is similar to the 2nd in that regard, the 7th leads and the 2nd falls.
Tensions Within Chords
Each of these linear single note tensions can be combined and when combined become chords. In Harmony in the Western World these notes are typically combined in 3rds, skipping every other note in the scale, Example: C major – C D E F G A B C, D minor – C D E F G A B C etc. The single notes within the chord maintain their qualities of tension within the chord. In other words the single notes tendencies will remain the same chordally as they are melodically and will thus give each chord its own harmonic characteristics in the key. This is why we refer to the notes in the chords as voices because each “voice” of the chord wants to go in its own direction for resolution, each individual note holds its own tension and path back towards the tonal center.
This is why there is chord “progression” because chords “progress” by fulfilling the harmonic tendencies of their individual notes. We say that the chord has both “vertical” or harmonic tendencies as well as “horizontal” or linear and melodic tendencies. A melodic interval is one that is played separately or melodically, sounded individually.
I hope this brief explanation of harmonic concepts helps inform the realities of your music making and maybe gives you a better understanding of the musical meanings of tension and resolution.