Posted 03/10/2016 by DarkEco
Creating sound for animation was a brand new experience for me and one that boosted my knowledge in sound design to a new level. Unlike my 'Connected' project last year consisting mostly of Foley work, Wall-E allowed me to delve much deeper into sound creation using synthesis. I can honestly say i have a much firmer understanding now of how to utilise certain types of synthesis to achieve specific tasks. The most notable for Wall-E was Granular Synthesis. There was no exact answer online describing how to create the iconic Wall-E voice, but a small amount of research that involved Youtubers attempts and Ben Burtts technology concluded that granular was somehow involved. I recorded myself saying "Wall-E" and loaded the file into my synth/sampler Omnisphere 2, which is a powerful tool for sound creation. Using its granular function i discovered that increasing the number of particles in the sample led to a much more robotic voice. Coarse pitch modulation and time stretching allowed me to create inflections and animation in the sound. I used the same patch for multiple other voice captures and uploaded a video tutorial to help others achieve the same outcome on cheaper or even free software. I also did the same for my wind effects, which involved modulating the cutoff frequency and resonance parameters of a noise generator.
One of the most frequent sounds in Wall-E was obviously going to be the sounds of his motors, so i focused on that first as it would require the most work and was likely to be the most monotonous task (like footsteps). I used Foley recordings of an electric shaver and a drill and created a number of unique sounds through pitch alterations and time stretching. I discovered (by accident) that if you cut the audio into small segments and pitch shift each segment to a different value it creates a much more robotic shift as opposed to smooth pitch modulation via an envelope. Overall i'm not too happy with how the wheel motors sound. They're a bit thin and could probably have done with more work, but i'm lacking any accessible objects that contain medium sized motors.
The most fulfilling sound creations for me were the ones fo his small cockroach buddy. I made him cute to the point that i actually wanted to keep him, which i see as successful sound design! All his sounds were built entirely on a synth. The squeaky noises as he runs into the scene were created by maxing out the oscillator hard sync and modulating the pitch to the highest possible point. This caused the waveform to "freak out", for lack of a better term. I don't understand the science behind why exactly that happened, but i managed to replicate the effect on a number of others synths. Using the mod wheel on my MIDI keyboard i could control the pitch and cause these amazing digital glitch sounds to occur. Changing the oscillator wave shape and the amount of sync gave even more variety to the sound. a few of these glitch sounds occur as Wall-E moves around. The clicking of the cockroaches feet was possibly the most satifying of creations, because it was the first time i had ever managed to come up with a theory of how a sound could be created and then successfully applied it to a synth. Unfortunately i'm unable to remember exactly what i did as i never noted down the process, which is frankly infuriating. The basic idea involved a very fast square LFO modulating the amplitude of the oscillator to create a fast on/off sound. Additional processing led to the sound clicking. Finally the 'purring' sound the cockroach makes when springing up after being squashed was created using the Wall-E voice sample. This was achieved by using fast repetitions of a small segment from the sample along with pitch modulation.