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A canvas for sound, science, and art
in the digital domain

Tech Notes and Tidbits

What is a LIATe (and can I get one at Starbucks)?
It's a term from mathematics, often called "Integration by Parts". It's a heuristic rule that helps transform the integral of products of functions into other integrals. It can be derived by integrating the product rule of differentiation (wiki) If u = f(x), v = g(x), and the differentials du = f '(x) dx and dv = g'(x) dx, then integration by parts states that:



When solving, one must decide which function to try first, and follow the rule:
  L: Logarithmic functions
  I : Inverse trigonometric functions

  A: Algebraic functions
  T: Trigonometric functions
  E: Exponential functions
The reference helps underscore the math behind the art

Facts about our LIATe:
  - Total pixel count (projection + control):  15 million 
  - Peak pixel calculation: 900 million pixels/second
  - System processing power: ~10 TFLOPS

Computers
The Theatre runs on only two, linked computers; A quad-core 'i7' iMac runs all audio and control functions, freeing bandwidth so a 6-core ‘Westmere’ Mac Pro can be dedicated exclusively to video processing. The tower's internal PCIe bay has been extended to a small external ‘render farm’ which houses and supplies additional power to the most recent generation of powerful graphics processors (GPUs). By writing programs that shift the computational load from the CPUs to the four GPUs, LIATe can generate up to 900 million 32-bit pixels per second, and has a combined processing power of around 10 TFLOPS (trillion floating-point operations per second) - that of a supercomputer not long ago.

Original Software
The main software used is the Max/MSP/Jitter programming environment.  LIATE's software is programmed in-house specifically for the multichannel conditions of the lab, and is not constrained by host-plugin configurations

Mixers
The only mixer used is in the Theatre, for the routing and fading of 32 input and 26 output channels. The main stereo mix bus is used only to feed the two subwoofers. In the control room mixing is accomplished ITB (in the box) or with a SPL summing mixer. Instead of a huge mixer, funds were used to purchase premium analog outboard gear, the majority of which actually uses vacuum tubes.

Connections
For it non-oxidation and easy maintenance, gold connectors are used exclusively in the control room, from the back of the mic through to the speaker connections. The patch bay also uses gold connectors.

Screens
Even LIATe’s screens are high tech. Designed by DNP of Japan, they are an optical instrument, like a giant lens, magnifying light from some angles (the projectors) and rejecting light from others (the room). Far from being just a spray painted surface over a cloth substrate, they are a multi-layered optical element rated for use with the 4k standard (twice that of HD, or 4 million pixels/image). Their extremely high gain (2.3) allows us to run our projectors in ‘eco-mode’, which is less bright but quieter and conserving of both power and bulb-life.