Are There Ghosts In White Noise?
It’s well known that when confronted with a particularly poorly insulated hotel room, some people choose to turn the TV to an untuned channel and crank up the volume to drown out the ambient sounds. White noise can actually be a surprisingly soothing sonic environment, but what else is going on in there?
White Light, White Heat
There is a discipline known as Electronic Voice Projection which many people will be familiar with from movies or pseudo-reality TV shows; its formal origins are generally dated back to 1969 when a Latvian by the name of Konstantin Raudive publicised his collection of thousands of static recordings, in which he claimed could be heard the voices of the dead. Not just any old dead people either; he seemed to have a particularly acute ear for the post-mortal coil ramblings of such infamous leaders as Stalin, Hitler and Mussolini.
Raudive isn’t an isolated practitioner; there are many who are convinced that EVP is a genuine conduit between the next world and this. However, it is more likely that any voices trapped in static are stray fragments of earthly broadcasts, and the listener can impose their own meanings upon them, much like auditory Rorschach blots.
Evolving Noise
Humans are actually quite good at piecing together fragments of speech over a noisy background; in fact, there would have been an evolutionary advantage to doing so – if, for example, someone were trying to warn you about the location of a sabre-tooth tiger during a powerful thunderstorm, or telling you there was no decaf in stock across the floor of a noisy cafe.
Interestingly, if you take a voice recording and intermittently replace sections with white noise, it is much easier to interpret than if you replace those same sections with silence – presumably due to those same evolutionary factors. White noise is more reminiscent of the swirling of wind through the forest (changes of wind direction can often have significant impact on what you hear), and sudden absolute silences don’t occur often in nature (and when they do, it’s probably too late).
In The Pink
So what is white noise anyway? Basically, it’s a random signal that doesn’t favour any particular frequency range – it has a constant power spectral density. Pink noise is modified so that different octaves have different absolute power spectral densities – however, as the human auditory system is non-linear and responds to lower frequencies differently to higher frequencies, people tend to perceive pink noise as having a more even balance of low/high frequencies. We also have brown noise, which essentially uses Brownian motion as a generator, and this will be perceived to have even more bass frequencies than pink noise.
For more details on EVP, try this recent article from the BBC, and if you need some White Noise therapy, you can try this White Noise Generator…