Garrett Rauck: Bestest Final Assignment Everss

The goal of acoustic design in cinemas is to reduce echo. That is, as new sound is being produced from the speakers, you don't want old sound to contaminate it, as this will create a deformed sound not intended by the film maker. The walls, ceiling, and chairs all cause the sound to bounce around, creating echo and, thus interference. In the case of the chairs, the sounds bounces more frequently and  more randomly, thus dissipating faster and reducing the effect of echo. The walls and ceiling, if left blank, will bounce the sound back without dissipating it very much at all and the old sound will be heard almost as clearly as when it was originally produced, ultimately causing interference with the new sound and ruining the experience...

Thus, we need to dissipate the sound on the walls and ceiling to eliminate echo and subsequent interference. One way to do this is with an acoustic diffuser. A successful diffuser disperses the sound evenly and randomly. This effect depends on the geometry of the device. 

To create a diffuser that dispersed sound evenly and randomly I wrote a Grasshopper script that creates an array of rectangular prisms of random height.

Create array of randomly sized prisms.

Result.

I was having trouble with Sonic responding to the overbearing geometry of the prisms, so I used the drape command to create a single surface that reflected the same random geometry of the prism panel. As you can see in the ray image, the sound was dispersed very evenly and randomly.

Draped surface which based on prism geometry.

Showing random, even distribution of sound from point source.

After successfully constructing a working diffuser geometry, I thought about how that geometry could change to reflect the architecture of my cinema. Around each of my theater volumes there is a concrete shell (see below). The geometry of the shell comes from various lines on the site and relationships between the theaters. I thought that the diffusor geometry could respond to the shell geometry to create a connection between the inside and the outside of the theater. That said, I wrote another Grasshopper script that uses relative distance to the regulating lines of the shell to manipulate a simple geometry. See below for better explanation...

Showing how circle radius is determined by proximity to regulating lines.

 The above image show how the regulating lines influence the geometry. As the proximity to a regulating line increases, the size of the circle gets smaller. I have used circles here just to demonstrate the gradient affect. Instead of flat geometry, what we actually want is to change the height of the surface so that it ungulates in response to the regulating lines. Below I used the same rectangular prism geometry and scaled it according to proximity to the regulating lines.

Array of rectangular prisms with height of each prism responding to proximity to regulating lines.

 In addition, beyond just responding to the regulating lines, we want the surface to also contain random manipulations throughout in order to disperse the sound properly. For some reason, I was only able to apply a random scalar in one direction, hence the appearance of rows in the image below. I ideally wanted to create a randomness more similar to the array of randomly sized prisms shown above. A greater understanding of Grasshopper's use of lists and data structures would help with that.

Attempt at random manipulation combined with responsive geometry. Only worked in one direction...

Here is a draped surface representation of the final result and the SONIC results...

Profile of draped srf.

Draped srf. Random striation depth. Still responds to regulating geometry.

Showing pretty even distribution. Could be improved by having multidimensional random manipulations.

In terms of material, I imagine this being made of wood. Wood is capable of absorbing some sound, so it would help with the diffusion. The wood wood also elegantly contrast the concrete on the exterior which it takes its geometry from.

THANKS ZACH FOR A GREAT YEAR!