"This particular example uses as its basis a sample of Feraliza on the violin, making a rubbery sound, totally unlike the type of sound you would expect from a professional violinist. The idea was for it to sound as though it were someone who had eaten so many beans they were blowing up in a similar way to Aunt Petunia..."
Feraliza has been working on some tricky psychoacoustic illusions as part of her studies of late. Some of you might be wondering, what is a psychoacoustic illusion? What does psychoacoustics even mean?
The Master Handbook of Acoustics (Everest and Pohlmann, 2022) defines psychoacoustics as "an inclusive science embracing the physical structure of the ear, the sound pathways and their function, the human perception of sound and the interrelationships of these."
According to Feraliza, even though she understands more and more about the science every day, she still considers it deeply in the realms of magic.
The illusion created here is an example of a Shepard tone. It's designed to sound like it continues to perpetually rise. This clip is only 30 seconds, but theoretically, the illusion of an ever increasing pitch could continue indefinitely. The illusion is named after the physicist Roger Shepard, whose research on the topic was published in the Journal of the Acoustical Society of America (Shepard, 1964)
To give away the "secret" to you, the effect is created using several loops, staggered in time, each with its pitch and volume automated so that as the higher tone starts to disappear another lower tone replaces it at a different octave. You can also use filters on more atonal sounds like white noise or engine noises! Getting everything just right so that the effect is smooth can be more tricky than one might think...
The sound used here didn't sound rubbery enough in different octaves so it was changed only over one octave and a filter was used as well to accentuate different frequencies within the overall ghastly timbre of the raw sound, which is being looped back and forth in a short section using another LFO on the wavetable.
There are a few different tutorials about how to make these, which are easily found on Youtube but Feraliza couldn't find one using FL Studio, so she made this wee video showing how she achieved it using this software along with the free Vital Spectral Warping Wavetable Synth plugin, one of her favorite tools in the Feraltech sound laboratory.
This isn't exactly a tutorial, but it does show what the illusion looks like on an EQ, the volume levels of the different tones rising and falling in the mixer and the LFOs working in the synth, making continual adjustments to volume, pitch, filter and sense of expansiveness with the stereo spread. You can see the staggering of the layers of sound.
This particular example uses as its basis a sample of Feraliza on the violin, making a rubbery sound, totally unlike the type of sound you would expect from a professional violinist. The idea was for it to sound as though it were someone who had eaten so many beans they were blowing up in a similar way to Aunt Petunia in Harry Potter and the Prisoner of Azkaban, (2004).
This sound will eventually form an important part of another project, but Feraliza wanted to share this as a stand alone post because we find this stuff fascinating, so give it a like if you are keen to hear more about psycho acoustic illusions or see and hear what other experiments are going on behind the scenes at Feraltech Productions.
Feel free to ask any questions in the comments!
References:
Everest, F. and Pohlmann, K., 2022. Master Handbook of Acoustics. 7th ed. New York: McGraw-Hill Education, p.43.
Shepard, R., 1964. Circularity in Judgments of Relative Pitch. The Journal of the Acoustical Society of America, 36(12), pp.2346-2353.
Harry Potter and the Prisoner of Azkaban. 2004. [film] Directed by A. Cuarón. Warner Bros.
The Master Handbook of Acoustics (Everest and Pohlmann, 2022) defines psychoacoustics as "an inclusive science embracing the physical structure of the ear, the sound pathways and their function, the human perception of sound and the interrelationships of these."
According to Feraliza, even though she understands more and more about the science every day, she still considers it deeply in the realms of magic.
The illusion created here is an example of a Shepard tone. It's designed to sound like it continues to perpetually rise. This clip is only 30 seconds, but theoretically, the illusion of an ever increasing pitch could continue indefinitely. The illusion is named after the physicist Roger Shepard, whose research on the topic was published in the Journal of the Acoustical Society of America (Shepard, 1964)
To give away the "secret" to you, the effect is created using several loops, staggered in time, each with its pitch and volume automated so that as the higher tone starts to disappear another lower tone replaces it at a different octave. You can also use filters on more atonal sounds like white noise or engine noises! Getting everything just right so that the effect is smooth can be more tricky than one might think...
The sound used here didn't sound rubbery enough in different octaves so it was changed only over one octave and a filter was used as well to accentuate different frequencies within the overall ghastly timbre of the raw sound, which is being looped back and forth in a short section using another LFO on the wavetable.
There are a few different tutorials about how to make these, which are easily found on Youtube but Feraliza couldn't find one using FL Studio, so she made this wee video showing how she achieved it using this software along with the free Vital Spectral Warping Wavetable Synth plugin, one of her favorite tools in the Feraltech sound laboratory.
This isn't exactly a tutorial, but it does show what the illusion looks like on an EQ, the volume levels of the different tones rising and falling in the mixer and the LFOs working in the synth, making continual adjustments to volume, pitch, filter and sense of expansiveness with the stereo spread. You can see the staggering of the layers of sound.
This particular example uses as its basis a sample of Feraliza on the violin, making a rubbery sound, totally unlike the type of sound you would expect from a professional violinist. The idea was for it to sound as though it were someone who had eaten so many beans they were blowing up in a similar way to Aunt Petunia in Harry Potter and the Prisoner of Azkaban, (2004).
This sound will eventually form an important part of another project, but Feraliza wanted to share this as a stand alone post because we find this stuff fascinating, so give it a like if you are keen to hear more about psycho acoustic illusions or see and hear what other experiments are going on behind the scenes at Feraltech Productions.
Feel free to ask any questions in the comments!
References:
Everest, F. and Pohlmann, K., 2022. Master Handbook of Acoustics. 7th ed. New York: McGraw-Hill Education, p.43.
Shepard, R., 1964. Circularity in Judgments of Relative Pitch. The Journal of the Acoustical Society of America, 36(12), pp.2346-2353.
Harry Potter and the Prisoner of Azkaban. 2004. [film] Directed by A. Cuarón. Warner Bros.
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