Editing Episode 13 - Aah, Robot!

It seems that my last tirade about Science Brian’s ludicrous sound effects has borne fruit. He has now started inserting apologies into his scripts to pre-empt my wrath. Well, sort-of apologies…

A snippet of AST script showing the sound effect "PUNCHING A ROBOT NOISE. SORRY PD, SORRY. I’M NOT SORRY."

OK, so it’s not really an apology, but I’ll take what I can get

But the thing is, ‘punching a robot’ is not a particularly difficult sound effect to create. It’s just a case of mixing the ‘cartoon punch’ effect that I’ve used in many previous episodes with any of the 272 hits* produced when you enter ‘metallic clang’ into the Freesound search engine.

So that’s that dealt with. Now, what am I going to fill the rest of this blog with?

Oh, I know – let’s talk about equalisation.

According to our old friend Wikipedia, equalisation is, “the process of adjusting the balance between frequency components within an electronic signal”. And, as the rest of the article is nigh-on incomprehensible to anyone without a degree in sound engineering or information theory,** that’s the last we’ll say of it.

In this context, equalisation is the process of picking out different pitches (frequencies) within a recording and making them louder or quieter. In the olden days (c.1970s), home stereos came with two twiddly knobs labelled ‘bass’ and ‘treble’ (and often a third, labelled ‘middle’). This allowed you to customise your funky music by ‘pumping up the bass’ or… doing whatever it is that cool people do with treble.

A bit later (1980s), ‘graphic equalisers’ became all the rage in the home stereo market, although they had been used by recording studios and audio buffs for many years. The graphic equaliser is a fancier version of the bass/middle/treble knobs, breaking the sound down into many more, smaller, frequency ranges to provide greater control over what you hear. ‘Graphic’ because you can represent the process as a graph, like so:

A screenshot of the graphic equaliser panel from the Audacity software

Graphic equaliser screen from Audacity (http://audacity.sourceforge.net/)

The graph shows what is happening to each frequency. The x-axis shows the frequencies from low (Barry White) to high (Pinky and Perky), while the y-axis shows how much the volume of each frequency has been increased or decreased from where it started. In the picture, the low frequencies at the left and the high frequencies at the right have been reduced by about 20 dB. But why is this relevant to AST? Well…

One of the characters in Name Calling is a disembodied voice emanating from an ancient (c.1970s) record player.*** This meant that I had to make a voice recorded in 2013 sound like it was coming from the dawn of time (c.1973). There are two steps to this:

  1. Equalisation. Small or low-quality speakers are very bad at reproducing high and low frequencies, so all you are left with is the bit in the middle. This gives a characteristic hollow sound reminiscent of a telephone or two-way radio. The graphic equaliser in the the picture above is set up to reproduce this effect by cutting out the high and low frequencies.
  2. Crackle. Nothing says ‘vinyl record’ like hiss and crackle. In reality, a well-cared-for record played on decent equipment will neither hiss nor crackle, and many audiophiles argue that the sound quality is in fact far better than that from a CD, mp3 or other digital format. But… we are in the business of creating audio pictures, which, as I’ve discussed before, means that things sometimes have to sound a bit different to real life before they will be recognised by the listener. In this case, our record has to have a layer of hissing and crackling added. Besides, a 40-year-old recording left in a disused museum doesn’t really count as ‘a well-cared-for record played on decent equipment’, so I feel entirely justified.

And there you have it. The miracle of audio equalisation brings a sense of ancient (c.1970s) doom to Action Science Theatre.


*No pun intended.
**It’s not much of an encyclopaedia, really, is it? If it were up to me, I’d call it Wikitextbook.
***For the young people in the audience, a record was a flat, circular piece of black vinyl on which music was encoded as spiral groove that started at the outside and worked its way into the centre. By placing a needle on… oh, look, a record is like an iPod but larger and rounder.

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