Consoles : 3 concepts

We can classify consoles in three categories, with slight variations inside each category : the traditional analogue console, the digitally controlled analogue console and the digital console.

The concept of the traditional analogue console :

Each audio signal follows a path in the console, from the top to the bottom of its "strip" (group of audio circuits that are dedicated to that path), flowing through each circuit along its way. The more possibilities per strip offered by the console (filters, EQs, compressors, noise-gates, etc.), the more circuits there will be. Since the action of each circuit on the audio signal must be modified by the user, a potentiometre ('pot') or a switch is linked to it on the console's surface. These controls act directly on the relevant circuit : the 'pot' is nothing else but the shaft of the variable resistance on the circuit, the switch, nothing else but the visible part of the switch mounted on the circuit board. So that human fingers can easily manipulate these controls without tweezers, the circuits are therefore 'unnecessarily spaced' along the signal path, which accounts to a total path of a dozen feet. If a console with many simultaneous audio signals in it is required, it will need X times the same controls in just as many strips, which isn't very cheap. And that's without mentioning that the strip becomes deeper and deeper and that unless you're built like Michael Jordan, it's impossible to reach the top of the strip while seated !

That big thing in front of the sound engineer (often called a 'console') is nothing but a remote control. From it, you can pilot the audio circuit racks, generally installed where it's convenient : On stage (SAJE MEMORY), which minimises cable runs such as "mike to console" and "console to FOH amps". In the machine room (EUPHONIX series), which minimises "console to multitrack" and "multitrack to console" distances, for instance. OK. In the Trident DI-AN, they decided to fit the audio circuit boards in the remote (in the console, duh !). That doesn't alter the concept :
The pots and switches that the engineer manipulates on the surface of the remote do not act directly on the audio circuits. The pots are in fact rotary shaft encoders which transform the physical position of the shaft into a binary value. I'll let you guess how the pressed/depressed status of a switch is translated in binary !!! These binary values are then sent to the relevant audio circuit. First advantage : the binary information can travel through hundreds of yards of cable without any loss. Second advantage, rather than a human being sending these binary values (manual operation), a computer can record/edit/read this information. You've got it = automation of all parameters, in real time if the automation software is well written. Once at the audio circuit boards, these binary values are converted to the equivalent voltage by digital to analogue converters. These voltages represent, for example, a specific mic gain value, or the exact frequency of a low-mid EQ, or the level of an aux send, etc... These voltages can also open or close a relay, hence replicating the position of a switch. Indeed, the audio circuits respond to the remote's manipulations, but indirectly, via the digital encoding of these manipulations. One last advantage, as if the ones above weren't already sufficient : since never a human hand will act directly on the audio circuits, they can be squeezed together, simplified. A complex "strip" on a digitally controlled analogue console takes up 4 times less space than the equivalent strip on a traditional analogue console sporting the same functions. The consequence of all this : reduction of console sizes ! Since there is no direct link between the manipulated pots and the audio circuits, we can very well imagine a console with only one set of controls (just one physical strip represented on the remote), which can be assigned at will to the audio circuits of strip n°7, then strip n°3, then strip n°15, etc... That's the option chosen by Trident for the DI-AN (except the faders, which are as numerous as the audio signal paths, don't get pushy...). If some people will freak out having just one physical strip in front of them, you can imagine presenting more physical sets of controls, say 16 times for example, which you could then assign to such and such pack of 16 audio circuit strips. This is the principle used by most manufacturers of digital consoles. They call that working in layers.
A problem remains though, that digital consoles also had to solve, and which the traditional analogue console will never experience. On a traditional analogue console, the controls are always in the "right position". With the arrival of the first VCA based automations, the manufacturers already had to come up with a solution to the fact that the physical position of the fader seldom matched the VCA's value. Now what to do when every single control of the console plays the same hide and seek game !!! Indeed, how do you reflect on a digitally controlled analogue console the fact that for example, an aux send, because of a change programmed in the automation, just moved from +3 to -5 ? There are several ways to solve the problem :   The video screen, indicating the "real" position of the setting, relevant to what the audio circuit is doing, whereas the physical position of the control on the console surface hasn't budged.         Motorizing the pots, and using non-latching switches coupled with an LED (LED lit = ON / LED off = OFF), therefore the controls are always in the right position. Very expensive ! The HARRISON Series X (which is a traditionnal analogue console) used such a solution. It's also the most expensive console ever built (more than $500 000 for a regular size frame). There's a good old dinosaur, I should have the Jurassic Audio Park try to capture a specimen !!!         Not using any pots ! It's the simple solution used by TRIDENT with the DI-AN (check out the beast in the Jurassic Audio Park). Each manipulation is performed via increment/decrement buttons, alongside which a multidigit LED display permanently reflects the value of the setting.         The "LED pot". A crown of LEDs surrounds each pot, lighting up to reflect the "real" position of the setting. As far as I know, AMS pioneered this system on the LOGIC ONE (which is a digital console). They named it a "logicator". This system, by far the cheapest and I must admit the easiest to read, has since then many times being copied. The MACKIE D8B (another digital desk), for example, uses this system. Let's summarize all this : this type of console brings the best of both worlds together, analogue (high bandwidth, know-how spread over decades, an "analogue sound") and digital (recording and instantly recalling settings, therefore automation of all parameters, reduced work surface, user defined layout, consistency of recalled mixes, etc...)

That big thing in front of the sound engineer (often called a 'console') is nothing but a remote control. From it, you can send instructions to a bunch of DSPs (Digital Signal Processor, processors specialized in a specific domain of calculation : calculations on audio or video waveforms) which will then imitate the behavior of traditional audio circuits. There are two variations to that concept : The systems where the DSPs as well as the converters and other audio circuits are in the console itself, such as the AMS Logic 3 or the YAMAHA 02R. The systems where the DSPs as well as the converters and other audio circuits are in racks, generally installed in a machine room where it's nice and cool, such as the LEXICON Opus, the SSL Axiom MT and most of the "bigger" digital consoles.