I’ve got to laugh on the odd time that I read a description of synaesthesia that makes it sound like some kind of mental disorder or abnormality of sensory perception. Sure enough, synaesthesia concurrents are perceptions of sensory experiences that are not triggered by things happening outside of the mind. They are experiences (not always sensory) triggered by activity happening within the mind (just like the meanderings of your normal constant train of thought). A synaesthete can experience sound as a synaesthesia concurrent triggered by a visual experience (the synaesthesia inducer), and might also experience a visual concurrent triggered by a sound inducer. Coloured music and visual animations that make sound are commonly-reported experiences in people who are, to borrow a phrase from Galton, “sane persons”. It might sound psychedelic to a non-synaesthete, but it is not far at all from normal perception, because life is full of events in which movement or some other visual stimuli is accompanied by a sound sensory stimuli: clapping hands, wind that rustles leaves, lips that speak, impacts that bang, or an explosion that is huge visually, sonically and physically. This pairing of sound and sight is so much a part of normal perception (in humans and other creatures) that it is commonly exploited in live entertainment.
I’ve had the opportunity to work in the past in the live entertainment industry and I also recently enjoyed the rehearsals of the Arcadia musical and special effects spectacular show currently at Elizabeth Quay in Perth. I know that there is a most startling loud roaring sound through the stage speakers that is typically created to coincide with a visual effect of an explosion of flames. It’s like some bloke presses a button somewhere and all hell breaks loose for a second or two. Arcadia uses this flame-roar sound to add sonic spectacle to the flame-thrower, and in the past while working I’ve also heard that sound used in complete isolation from music in a sound check of another spectacular stage show. At the risk of ruining the magic, I’m revealing that the sound that goes with the flames is an artistic artifice. I guess that any real sound that the flame effect makes has been judged to be not sufficiently loud and spectacular enough, and a suitably awesome sound (a recording of what I can only guess) was created to go along with the visual effect of flames from hell. I think this shows just how important crossmodal experiences are to live entertainment shows that are based on spectacular sensory experiences. The sound must equal the visual spectacle.
There are also many other ways in which sound and sight are linked in stage shows and special effects in entertainment. Musicolour lighting effects have been around since my Dad created disco equipment in our lounge using it back in the 1970s, and similar but much more developed lighting effects can be seen in the body of the Arcadia spider. Technology is not always required to artificially marry lighting and sound, as the amazing red and blue man electricity show features electrical discharges that look like tamed lightning that naturally give off a crackling sound along with the white light. But then again, I’m now wondering whether that sound is for real. Anyway, it’s wonderful, mad, sensory fun. I love it!
Postscript January 2017
I think the phenomenon of “quiet fireworks” adds more support to my point that spectacular public entertainment special effects often include the deliberate timing of sound and visual effects to happen at the same time to create a form of artistic synaesthesia, because while fireworks typically have bangs and flashes at the same time, the bang part of the spectacle is not essential or inseparable.