../ The fun part is that we can be duped.
(from Part One)
How are we duped? This is where Digital Signal Processing or DSP makes an appearance.
In essence what happens when we hear things? We have two ears that are able to very quickly process direction of sound via our brains and to do so accurately. It’s what helps us run AWAY from the lion because we can hear where it is even if we can’t see it.
The same sound from the lion enters our brain processing unit from two sources – our ears. Based on what each ear microphone is picking up our brains can determine the origin of the sound immediately and then we get to run faster than our fatter and slower peers who do us all a favour by being eaten.
It’s that source sound wave that is all important. If you can create it as if it were in the open veld entering our ears in exactly the same fashion from say within a car, your brain would process that sound in exactly the same way.
Of course your eyes would discount the likelihood, but if they were closed (which is why it is far easier to listen when in reference mode with your eyes closed or in a darkened room) your brain would be fooled into believing what you had just heard.
It is however a stupendously difficult thing to get right. You need to ensure that the sound waves hit your ears at exactly the right time with exactly the right form as they would in the wild. And not too many people have made accurate recordings of lions chasing you from the rear and those that have are all dead.
But stupendously difficult has never really stopped people before. Plenty of snake oil has been sold to plenty of suckers and many smokey mirrors abound in human history. DSP is not one of them however, but it is by no means a certainty of even getting close.
Just think about being in a car. It is an incredibly hostile environment for sound reproduction. Quite possibly the worst of all environments to considered with perhaps the exception of an outhouse.
You have glass, plastic, leather, metal and ‘other’ as sonically reflective surfaces all with differing magnitudes of influence. And then you have all of these in a confined space pointing in literally hundreds of different directions.
A single note, just one, played on identical system in different cars will have different properties by the time it reaches your ear because of the different interiors.
How many notes? Reverberations? Harmonics? are there in any single piece of music?
(For fun and homework watch this https://www.youtube.com/watch?v=AWVUp12XPpU. And then get some recordings of it and listen to them). If it doesn’t move you to tears you’re dead inside.
What DSP does is to try and shape the wave forms in the digital domain to recreate them as they should be to hit your ear to create that believability. In other words it attempts to take all the myriad factors into account and tune the digital source to an analogue form that recreates the impossible.
And I do mean impossible. That should be obvious by now.
But that doesn’t stop us from trying…
