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COMPUTER MUSIC TUTORIAL (III)

Tutorial about composition of computer/digital music: creative variations applied to a musical composition.

Creative Variations

Up to this point, the example composition is a fairly plain rendition of Frère Jacques, played once only; if we listened to it repeated times it would get old fast. When listening to professional music we may notice that certain variations are usually introduced to keep the compositions interesting enough. There are many ways of doing this and in this third chapter of the tutorial we will see a few of them, to finally arrange an improved and longer version of the example composition in a playlist. So what can we do to spice up this short musical piece? Here are some basic ideas:

Changing instruments: in this variation different instruments take turns on performing the lead melody.

Varying the melody: in this variation slight variations are introduced either in the musical structure of melodies (the notes) or in the way that those are arranged (the pattern of verses or refrains).

Changing the key: in this variation the notes of a melody are rearranged as required to match a certain key (either major or minor), in the attempt of achieving a dramatic effect in the character of the composition.

Changing the tempo: in this variation the number of beats per minute is changed to achieve a notable impact in the character of the composition. Tempo usually keeps the same value throughout the entire composition but it is also common in classical music to use different values in certain sections or passages.

Changing the style: in this variation the composition is adapted to one of the many existent music styles (rock and roll, pop, electronic, folk, etc...). This is probably the most complex variation, as it requires knowledge on the characteristics of a particular style and often to apply modifications on each layer of the composition.

To understand the following examples you should be familiar with musical concepts such as keys, scales and chords. As I did before, I have added samples as MIDI files which can be loaded in the piano roll to see and listen to the alterations effectuated in the composition.

In this first example the major key (C major) that the original composition uses is changed to the equivalent minor key (C minor). Through this change the famous lullaby should acquire a mysterious, dark character which should be able to transmit a somewhat creepy feeling, the envision of the rhythm of a grave being dug by hand. For this kind of music a majestic church organ would be a perfect instrument.

The recipe for a minor key requires to flat the third (E), fifth (G) and seventh (B) notes of the scale. To further increase the effect the tempo is slowed down and the piano and guitar are replaced by an electric organ, which will take care of the melody and chords alike. The bass remains almost the same but now the pattern is the same throughout the eight measures. The drums have their overall pattern deeply modified and alternate between acoustic bass drum, closed hi-hat, crash cymbal and cowbell. The settings for this composition are: Lead -> FL Keys [Roto Organ] 3/6; Chords -> FL Keys [Roto Organ] 3/6; Bass -> BooBass [] 5/6; Drums -> MIDI Out [Channel 10] 5/6.

Note: if MIDI Out does not sound and you cannot find the reason behind this, you can add to the master channel of the mixing console the device called Fruity LSD and then set the MIDI port of both components to the same value.

Piano roll example minor key
fj_variation_minor_key.mid ~ fj_variation_minor_key.mp3

In the second example there is a variation in the melody and the leading instrument is a fuzzy guitar. The 1/4 notes are broken into 1/16 note trills, but the melody is still recognizable. The other channels have been modified as well, as the following picture shows. Chords are played by an electric organ, whereas bass and drums are played through the same instruments than in the previous example (BooBass and MIDI Out, respectively). The bass is showing more complexity than in previous examples, showcasing upward and downward arpeggios and a notorious fragmentation of notes. The settings for this composition are: Lead -> Plucked! [] 3/6; Chords -> FL Keys [Roto Organ] 3/6; Bass -> BooBass [] 5/6; Drums -> MIDI Out [Channel 10] 4/6.

Piano roll example lead variation
fj_variation_lead.mid ~ fj_variation_lead.mp3

In the third example the first eight measures are occupied by the composition completed in the previous chapter. The subsequent eight measures contain the same melody but with changes in the chords, bass and drums. The new chord section follows, roughly, the pattern G-C-G-C-F-C-G-C, whilst the new bass section introduces very remarkable variations which, if listening closely, might lead into some of the chord changes. The settings for this composition are: Lead -> FL Keys [Piano] 3/6; Chords -> FL Keys [Roto Organ] 3/6; Bass -> BooBass [] 5/6; Drums -> MIDI Out [Channel 10] 4/6.

Piano roll example chords variation
fj_variation_chords.mid ~ fj_variation_chords.mp3

Eventually, I decided to arrange a larger composition by joining the original with two of the variations (those written in major key). For this task I have used the playlist, a window filled with a grid in which different sections of a composition can be quickly arranged, allowing so to test different musical structures without having to go through a copy and paste mess in one or several piano rolls. Each of the different musical structures contained in the playlist is known as pattern. All of these musical structures share the same channel list, so we have to add all the required channels in the list and then fill or leave blank the different piano rolls as required. When using the playlist to arrange a composition we have to switch the playback mode to SONG to be able to play the whole composition.

In the following picture you can see that the playlist contains three different patterns (fj_original, fj_var_chords and fj_var_lead) and a total of five instances or passages (one fj_original, two fj_var_chords and two fj_var_lead). If using letters of the alphabet to refer to the different patterns, I can say that I have arranged the composition following the sequence B-A-C-B-C, out of many other possible combinations. The second pattern (fj_var_chords) includes a copy of the first pattern (fj_original), so the original repeats a total of three times whilst the two variations repeat two times each; this is equivalent to seven times the length of the original composition. For filling in every pattern the four channels that each pattern has, I had to import the corresponding MIDI track separately into each piano roll.

As a plus, I have created a vocal section in Vocaloid Miriam to accompany the original leading melody. I used Cool Edit Pro to trim and amplify the waveform created by Vocaloid, and also to enhance the quality of the voice through a chorus effect. Then I loaded the waveform into FL Studio by means of a Sampler channel, in which the waveform is triggered by a single note located in C5 (the root note in which samples play at their real pitch). For a better understanding I have drawn the note as long as the duration of the vocals, but this is not necessary, as the sample will play on its totality regardless of the length of the triggering note.

I have used for this final composition the same instrumentation than in previous examples; the Lead 1 channel corresponds to the piano used in fj_original and fj_var_chords, whilst the Lead 2 channel corresponds to the guitar used in fj_var_lead. A varied instrumentation will result in a colorful composition. The settings for this composition are: Lead 1 -> FL Keys [Piano] 4/6; Lead 2 -> Plucked! [] 3/6; Vocals -> fj_original_vocals.mp3 5/6; Chords -> FL Keys [Roto Organ] 4/6; Bass -> BooBass [] 6/6; Drums -> MIDI Out [Channel 10] 4/6.

FL Studio 5 (frere jacques final arrangement)
fj_original_vocals.mp3 ~ fj_final_arrangement.mp3

For a last example, I have created a similar task in the multitrack view of Cool Edit Pro. I reduced the amplitude of each sample by six decibels because otherwise the overall amplitude of the mix would exceed the limit of the clipping zone. Note that I have entered the proper tempo and measure information in the program to achieve a perfect fit in the time line (the whole composition has 56 measures, or seven by eight).

Cool Edit Pro 2 (frere jacques final arrangement)
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