For example I am making a 16 bar chord progression for a verse of a song and choose to use the I , IV , V chords of a major scale.. How can I put these chords in a nice rythm so they sound good and how long should each chord be played ideally?
This is an artistic decision for you to make!
The speed at which chords change is called harmonic rhythm. There are songs that change chords twice a measure and get a hectic energy for it, and pieces that change chords once every two or four measures, drawing out each chord's sound dramatically. In addition, as with regular rhythms, harmonic rhythms can be syncopated so that they start a partial measure (sometimes beat) before or after a measure change.
Each harmonic rhythm has its own effect. You know better than anyone else which rhythms would be best in your situation.
Generally speaking, 4 bars is as long as a song will stay on one chord.Even at that the single chord can sound tedious, so towards the end it is often changed, sometimes by adding a 7th. Other songs get away with only 2 chords, but change every bar or 2 bars. 'Dance the night away' and 'Jambalaya' come to mind. Theoretically the concept seems boring, but they are both popular songs.If you do stay on one chord, try to move the melody around, and conversely, maybe keep a more static tune when the changes are frequent.
Listen carefully to the hundreds/thousands of songs that employ only 3 chords - almost inevitably the I, IV and V, and you'll get ideas. Don't think you'll come up with something revolutionary - it's more than likely all been done ! But it won't stop another load of 'three - chord - wonders' being written in the next few years !
I agree with other posters that it is important to make this decision for yourself, no one here can have the "right" answer. Having said that, here are a few progressions to consider:
- I - IV - V - I
- I - V - IV - I
- I - I - IV - V
- I - I - V - IV
- I - IV - I - V
- I - V - IV - V
- I - IV - V - IV
- V - IV - I - I
- V - V - IV - I
There are a few ways to "categorize" these progressions, including those that start with I (1,2,3,4,5,6,7) vs those which start with V (8,9), those in which the I chord appears twice (1,2,3,4,5,8) vs those in which the V chord appears twice (6,9) or the IV chord appears twice (7), those which "cycle" through the chords (1,2,3,4,8,9) vs those which "oscillate" between certain chords (5,6,7). These are not all the possibilities, just a few popular ones to get you thinking about your options.
So that takes care of the "order" of the chords, but what about the "length" of each chord? I would suggest starting with one chord per bar, which means all the above phrases are 4 bar phrases. Then just repeat each phrase 4 times (for a total of 16 bars). Depending on your tempo, if the harmonic movement feels to slow or too fast, just half or double the number of bars for each chord respectively.
Notice here that each chord is always played for the same number of bars. This is the simplest approach to song structure you can take. As you become more comfortable with how to put chords together, you can experiment with giving certain chords more measures than others. It doesn't change the harmony so much as it changes the feel of the song, the tension and release, the emotional impact and the story you are trying to tell. So that means there are really no rules! Just do whatever you think sounds best.
Chords of I, IV and V are in certain relations among themselves.
They are the "strongest representatives" of the three harmonic "functions": the tonic, the subdominant, and the dominant. It's because their base notes are all a fifth apart. Therefore, each of them is explicit in their meaning. If you think in functional terms, such as, e.g. "calmness", "movement", "tension", it may be more obvious which "rhythm" to use. But, "harmonic rhythm" may not be the same as putting the chords into a "nice rhythm", and depending on other factors, you could make a lot of rhythmic content on only one chord, which introduces purely rhythmic tension, which can also underline the overall tension.
You also have to pay attention to the cadenza, or the ending of the chord progression, or the progression of the phrase: it could end on the V, as well as on the I.
It depends on the genre of music you are playing. If you are playing reggae music, you will play the chords very quickly, you will just "strike" them it must be like 1/16th or 1/8th. If you are playing soul music it will be longer. Ihe s believe it's all about feeling and groove, just play as you feel them. Music is art. Theory is important but there is also a subjective part of the art that gives you a certain freedom. If not, all songs would sound the same.
i agree with previous posters that there is no hard and fast rule on how long and how much each chord should be played. If the song is upbeat or high spirited, i might play the chords twice in a bar, or if a part of the lyrics needs an emphasis i could even play the chords at each beat. Sometimes there is a dominant prolongation that can encompass more than 3 bars. To avoid monotony, i would vary the chords - eg. Using V7 and/or V7sus4 after the dominant triad. Sometimes iii or even #iv dim can be substituted for V. Hope this helps☺