Mark Terra-Salomão | Assignment 6B: Best Final Assignment Ever!

Not to turn the best final assignment ever into a dissertation on moral philosophy, but it's my belief that now that the final project is done it would be mildly disingenuous and not particularly expedient or useful on my part to actually design an acoustic ceiling and talk about it as if I had done it before the fact. (Not trying to call anyone out here or anything; I just don't feel comfortable personally with talking about work I've done after the fact as if I had not.) So, in my usual iconoclastic ways, I have decided to revive an old favorite and have essentially placed a scaled-up version of Alvar Aalto's Viipuri Library lecture room acoustic ceiling into my large 120-seat theater. I've always wondered how accurate Aalto's hand studies of the acoustics were, and / or whether a computational tool could recreate these studies in a fraction of the time it took Aalto.

I used Sonic's complex surface casting function. I placed the point where the theater's speaker room would be, simply because that's where most of the sound in the theater would come from (and also because Aalto's ceiling was designed to accommodate one source point at the front of the space). Ignoring the fact that Sonic likes to raycast through the surface, it seems that the acoustics of Viipuri would actually work quite well for this theater. And why reinvent the wheel, amirite? (WRONG!)

Anyway, if I were to 3D print this "tile" it would just have to be immensely scaled down, as it is not so much a tile as an entire ceiling datum. Indeed, this is what I have done with the STL file.

The scaled-down tile compared to the overall ceiling assembly

Assuming that I would actually place this object into my theater - which I already established I wouldn't, but let's try and suspend our disbelief - materially it would be more or less the same as the Viipuri Library's ceiling; that is, shaped sitecast concrete clad with high-quality wood. This is only partially a shameless cop-out, as there is a good reason to use wood - many kinds of wood have good acoustic properties. I'll never forget this because it was ingrained into my mind by my elementary-school music appreciation teacher. She would always complain that when they restored the school they didn't replace the music room's crappy metal doors with nice, acoustic, soundproofed wooden ones. Specifically I think I would use Australian or African blackwood for the ceiling cladding, as blackwood is a tonewood (wood used for making musical instruments) that according to guitar makers (via Wikipedia) is prized for "warm, clear, bright sound with good volume."

Kmquinn_Assign6B

When thinking about acoustics and how they function in theaters it’s important to understand that even though you have speakers and amps, the theatrical space for sound is still important. Sound doesn't all come from one place, there is a dynamic about it, which is why sound is used to be able to locate the position of an object in space, based on what ear you hear things from and how far away the sound was made. In theaters speakers are set up so that you have voices and the main dialogue coming at you from the front of the theater while all the background noise and other sound effect hit you from the side. In scary movies the switch it up which is why you feel a sense of being watched because the noise is coming from behind you. The same thing happens in headphones, the bass and tenor will be split between the right and left headphone. (When you listen to duet both voices don’t come out the same ear). This is important to recognize because it means that in theaters you can’t have point direction when it comes to acoustics. Point direction is what happens when you have a funnel type room or a concave shape. It points all the sound particles into one specific point. In theaters you want an equal spread of the noise, so that every seat is the best seat. The best way to do this is to have no parallel walls, floors, or ceilings. And if you want to be really fancy you should have them curved even. My acoustic tiles are all curved tiles stuck against a circular room in to absorb and diffuse sound evenly.  

Convex curves spread sound evenly

Concave curves spread sound with a point-source

A diagram about concave and convex curves

The Curved acoustic tiles pinned against the curved wall

The curved wall of the theater space and the acoustic effect on it

A picture of the .STL file