Creative Audio Processing
11 - Theory of organicity

 

 

Where sound is compared with food - and organic sound to organic food. This is not a joke ! The comparison may sound weird but what's actually behind it is quite interesting.

 

- Preliminary explanations One of the basic ideas and a good starting point is that digital or "artificial" sound need to be adjusted to human perception, otherwise it sounds cold, harsh and unsatisfying. Let's be more specific and take a realistic example : I have created a set of sounds with a basic digital algorithm written in Max MSP or something similar. The timbre, though complex, is not satisfying. Whenever I play it loud, it's painful, and when I play it at a normal level, it doesn't bring anything. Furthermore, it's cold and sterile. I put these sounds on tape, with a high input level - thus taking advantage of non linear behavior from the magnetic tape itself. What happens ? The timbre is more satisfying. It's got grain, and it's not as painful. I can also let it pass through tube gear at high level - it gets even better. Starting from that example, the theory can be described as such : there is some sort of natural balance in physical phenomena that's needed to get perceptively suited sounds. Purely digital phenomena, unless purposely "bent" to suit perception, lack that balance. Indeed, it's a bit like organic food or plant medicine : try to extract a given molecule from a plant, suddenly there are a lot of secondary effects. Also, processed food tends to be extremely boring at length - there is always the impression that something is missing. The organic food trend can to some extent be compared to the transition between the 80's and the 90's in popular music. Pop music from the 80's was often cold and clear, pop music from the 90's was more complex in terms of timbre, "vintage" instruments, grainy samples form vinyl etc....

 

- In practice : digital vs analog - lofi vs hifi - grain   Let's get to the point, and let's be more serious. This theory may sound loony for the moment - so let's make eight "serious" remarks and observations that backup the point at hand. 1. digital audio is often considered as sounding "cold" => this is probably a matter of grain - analog audio brings microscopic irregularities that digital audio usually doesn't bring. 2. digital EQs, especially inside a same host software, sound almost the same => grain, brought by the host audio engine, is even likely to override the EQ's intrisical characteristics 3. the best EQs (like the Manley Massive Passive or the GML8200) are analog => in processing, situations that are not entirely deterministic can bring better results 4. if the ear can be considered as an ADC, the analog pre processing before the actual conversion is extremely complex => this shows that highly non linear signal processing is not necessarily a problem, on the contrary. 5. putting an ADC in a mike (thus minimizing the signal's analog path) gives poor results => reducing the unpredictable to zero is a bad idea 6. electrodynamic speakers give more comfortable results than electrostatic speakers, though they are less accurate => the main difference between electrodynamic and electrostatic speakers in terms of behavior lies in the dynamic aspect : transients are more accurately rendered on electrostatic speakers, which have a very low integration time. This can bring the hypothesis that an audio system is more suited to the ear if its integration time is close to the ear's integration time (~50ms) 7. non linear processing (like processing the signal with a tape or a tube) often give comfortable, "signal balancing" results => it's better if processing includes a physical aspect - purely mathematical signal processing (like digital) may bring unbalanced results 8. complex reverberations (like outdoors natural reverberations) are often very nice - meaning a lot of details, a "liquid" aspect etc. => another hint that detail, complexity, grain, are important.   Conclusions : summing up those eight examples, we can say that : microscopic aspects of a processing tool or algorithm are important - complexity in details is important - entirely deterministic systems are not a good idea - emulating the ear's behavior can be interesting... many important points.

 

- Another aspect of the theory : linked evolution parameters   In common audio devices, a parameter is a often a single parameter. Meaning : if I take a ProTools track and automate the volume, it will only concern the volume. But things don't go like that in real life : when I speak louder, my voice doesn't only get louder, the timbre also changes, the intonation is not the same etc. Conclusion : changing the volume only may be an artificial concept. To be organic or even "realistic", a volume slider should include other parameters.   Examples : 1. Moving away from a sound source is : - level goes down - high freqs go down, low freqs go down, medium freqs get more prominent - direct sound / diffuse sound ratio gets down - transients get less accurate, overall dynamics is reduced 2.Doppler effect, same phenomenon as example 1, plus - pitch gets lower when the object passes 3. A violin player plays "louder" - levels gets higher - vibrato gets faster - harmonic / noise ratio gets higher - level of the harmonics / level of fundamental gets higher 4. An electric guitar player (+ amp with overdrive) does vibrato - vibrato gets indeed more important - the level of a particular harmonic gets drastically higher (fake feedback effect) - the overall level thus gets higher - sustain gets more important

 

- More conclusions ? There are many more things to be said on that subject, but we're going to stop here. One conclusion would be that audio tools might be greatly improved by becoming more organic - traditional instruments have a very organic behavior, and it's quite difficult to get bored by the sound of a cello, even though the actual instrument was created many centuries ago. A more modest conclusion is that when creating or processing sound, this theory gives interesting landmarks and ideas : synchronizing level and EQ automations in ProTools is easy, it can give interesting results... using a tape recorder is also easy, and it often brings good results in terms of "liveliness" and "warmth". Also, knowing why and when to use an analog EQ in non linear regime instead of a standard EQIII Digi plug-in is quite useful. People usually do that out of intuition, this theory of organicity puts that into words.