I mentioned featuring multiple rhythms in the previous article on Musical Creativity. In this one, I'll introduce multiple speeds.
Different Speed
Similar to how different beats are accentuated due to the accents of the individual time signatures in the previous article, we can see a similar effect with varying the speed of one or more of the tracks.
To demonstrate, I'll take you through a basic sample song. Here's a screenshot of the song.
It consists of 3 channels:
Treble synth with a repetitive pattern
Bass synth with a repetitive pattern
Drums with a repetitive pattern
I've chosen artificial sounds to make it easier for others to replicate. Just bring up any softsynth and select two different patches. I changed the patches until I found something that worked for this demo.
I haven't done anything interesting with the notes. They're largely just repetitions of A or the A major chord with a few other notes thrown in. Not much thought to any melody. It should help focus on the speed.
The Treble Synth
Set the song speed to 160bpm
Programme channel 1 with the treble synth. That's the sound you hear at the beginning of the song.
Add in some notes and set to loop
Export a region of this track only. Think I exported about 60 bars, but only used about half of that. It's worth having the original bpm of 160 in the title of the exported file
Import this exported bounce into an audio track
Mute or delete the original midi track
The Bass Synth
Mute the treble synth
Programme channel 2 with the bass synth. This is the other musical sound that comes in after the 2nd bar and drops out as the speed changes.
Add in some notes and set to loop
The Drums
Programme channel 3 with a drum synth.
Add in some drum notes and set to loop.
Tempo
Hit play and change the playback or
Set up a separate tempo track and change the tempo there
I used a tempo track set to 160bpm at the start, then change to 175bpm, then to 163bpm. You can see these changes in the tempo track. At each change, I've dropped out the drums and bass to make it more obvious that there's a change.
The Results
Channel 1 will playback at the same speed of 160bpm regardless of the song's tempo. The drums and bass change speed along with the song's tempo. This results in different accents as the rhythms combine. 175bpm works well, whereas 163bpm sounds more cluttered. Depending on the tempo, notes and original source tempo, the result can add an interesting rhythmic quality.
Why a drum synth? It doesn't have to be, but you need a loop that will change speed as you change the song speed. So don't use an audio file that won't stretch as you change the playback bpm. Apple loops will work well within a limited range.
Beat Frequency
If two sounds are of close enough frequency and similar enough tone, you may experience a 3rd note. This subjective tone is produced in the same way as the 3rd note you get when tuning two guitar strings to each other. If you can hear the 3rd note, then you know the strings aren't in tune.
The beat frequency is the note caused by the interference and reinforcement of the two source soundwaves. It can be used musically in its own right, although I've used it more often to create tension and then resolve.
A diversion into low numbers
Due to playing musical notes, rather than sine waves, it's going to be a lot more difficult to guess what the subjective tone will sound like or if you'll be able to hear it.
For instance, 8 notes to a 4/4 bar at 120bpm means that notes are playing at a frequency of 1 ÷ (60s ÷ 120bpm ÷ 8 notesperbar x 4 timesignature) Hz= 4Hz. We're not going to hear 4hz and that's just for one of the source notes, let along the difference between that source note and another in order to create the subjective tone. However, and it's a big however, the subjective tone can still be audible since each of the notes has it's own amplitude pattern. It's the combination of the two source tones that brings about the potential of an audible subjective tone.
Best thing to do: experiment. It's easier to spot in the treble range. I don't think there's one in the mp3 here, but there was in an earlier version where I had a different tone. That was the only difference. What else?
Introduce melody and/or different rhythms. The loops above were just to show the concept.
Vary the tempo gradually as opposed to the step-changes I used.
Introduce more than two musical instruments
Use frequencies that are very close together for uncomfortable results
Use frequencies that are multiples of each other (or at least have common denominators) for a more synchronised rhythm
Focus on the beat frequency
Part of a series by Award Soundsoffering a selection of creative ideas to kick-start or rejuvenate a composition.