Waveform Basics: A waveform is a visual representation of a curve of sound.
When you’ve uploaded your audio to the program of your choice, you’ll see the waveform on the timeline.
The horizontal line = time.
Vibration causes molecules to wobble = radiating out in the jagged 'splatter' as seen below.
The upright line = measures air displacement. If there is small disturbance (someone humming in the next room) displacement is small and therefor the 'splatter' will be minimal.
Each curve is called an oscillation, this is the 'up and down' wiggle of the splatter. Air is displaced both up and down the vibrational disturbance. The bigger the disturbance, the greater the fallout!
The high spikes = peaks.
The low curves = troughs.
Once you get used to listening and watching the cursor move along the line, you may begin to ‘read’ it, begin to recognise certain patterns such as your own voice, a sniff, or the sound of a car engine turning over in the distance, for example.
It is possible too to look ahead and pinpoint where a good EVP may be – although not always. Often they may be quiet or hidden beneath other noise, but once in a while, you’ll be treated to a stand-out class A that jumps almost off the timeline it’s so obvious!
From analysing my own captures there seems to be a general rule of thumb. EVPs most of the time, the good ones, appear to be almost diamond shaped. There of course may be exceptions to this theory (of course, nothing makes sense in this field!) but here are a few examples.
I am currently in the laborious process of building a visual catalogue of as many regular sounds as I can, to better understand what they look like in waveform. So for example, I know that a car in the lane behind my location looks like a fuzzy pipe cleaner. I know that a friend of mine with a very powerful voice who's had professional singing coaching has a representative waveform that looks like an enormous cresting a wave, whereas my other quieter male friend, has a muffled waveform with low peaks and hardly any troughs at all.
Jackdaw chicks look (on a timeline) totally different to Herring gulls. Sparrows chirping and tweeting in the bushes in the yard of the prison in Shepton Mallet are nothing like either of these other birds, and a scuffling footstep is remarkably like the bumbling low rumble of a wood pigeon. Note down footsteps in boots, footsteps in trainers, the echo of your own voices in a certain room. The list is eternal.
All of these things can be screen-shot, labelled up and kept as a visual reference. Naturally everything will differ depending on environment, weather, humidity etc, so nothing is ever going to be exactly the same, but I think it's important to at least try to understand your most regular audio captures.