“Book ov Convolucions” (DVD)
Book ov Convolucions (DVD)
con·vo·lu·tion (k?n’v?-l??’sh?n)
n.
- A form or part that is folded or coiled.
- One of the convex folds of the surface of the brain.
In mathematics and, in particular, functional analysis, convolution is a mathematical operation on two functions f and g, producing a third function that is typically viewed as a modified version of one of the original functions. Convolution is similar to cross-correlation. It has applications that include statistics, computer vision, image and signal processing, electrical engineering, and differential equations.
In linear acoustics, an echo is the convolution of the original sound with a function representing the various objects that are reflecting it.
In artificial reverberation (digital signal processing, pro audio), convolution is used to map the impulse response of a real room on a digital audio signal. Common ways of generating this impulse include bursting a balloon and firing a starting pistol, though more accurate results can be achieved by recording playback of a sine sweep, which is then ‘deconvolved’.
These short films together form a ‘book of convolutions’, documents and processes that seek to uncover the secrets of familiar spaces. Many of the sounds in this piece are made from site-specific recordings which have been convolved with the captured reverberations of these spaces, ambience convolved with itself, everyday sounds take on the shape of a handrail, a creaking door, other voices. I am standing in a room, similar to the one you are in now..
Equipment used
Various microphones (Sony, Sennheiser), Fostex recorders, Genelec & Tannoy Reveal monitors, Sony PD-150 camcorder, balloons
Sony Soundforge, Acid, Vegas, DVD Architect
Voxengo Pristine Reverb, Deconvolver
Waves IR1
Ableton Live
The concept
There are 3 parts to this project.
- Capturing impulses from the Atrium and fire escape staircase for use in a convolution reverb
- A fluxus-inspired performance taking place on different levels of the Atrium
- A DVD (for installation on an iMac in the Atrium) containing evidence of the above, recordings using convolution, exploring themes of space, cultural ideas about reverberation, and working with photography and video.
Some ideas relating to the concept:
To get to know a familiar space, its inhabitants, routines, quirks, its layers of sound and searching for quiet moments
A territorial pissing
An exploration of acoustic, virtual, public and social space
How two convolved sounds act upon each other has interesting implications.
I was interested in exploring Alvin Lucier’s “I am sitting in a room” and how this experiment can be applied both to sound and to video (Mary Lucier and others), and also how this idea works in practice with a virtual space.
Convolution Recordings
These consisted of the following:
Using bursting balloons, handclaps, foot stamps, shouts, overtone singing, striking metal handrails, squeaking doors, setting up a sine sweep apparatus to generate impulses. These were then used in recording sessions to generate material for inclusion on the dvd.
The sine sweep recordings are deconvolved to produce a bang-like impulse (bursting a balloon is the quick and easy way to excite the response of a space and thus generate a decay that can be applied real time as a reverb effect)
Using a genelec in the stairwell produced a reasonably flat response, though it lacked enough power to excite the space fully.
Tannoy Reveals in the Atrium (L/R and L+R) were significantly less flat in their response and produced impulses lacking low frequency information. An ideal setup would be to use a 2.1 setup with as flat response and high output as possible.
A fully inflated balloon produced a loud enough impulse, though this created problems with distortion and SPL, capturing low frequency information and noise floor from lesser quality microphones than those used for the sine sweeps.
A recording of a Shepard tone (with a slight delay) emanating from my Roland Cube on the stairwell basement level, captured from the top of the stairwell.
An attempt at overtone singing, aided by the stairwell’s natural reverb and converted to an impulse, which became a drone when used in Pristine Reverb.
A recording of a vocal incantation, glorifying the virtues of the stairwell, its reverberation and paying tribute to Alvin Lucier.
Themes of religious significance of ‘holy spaces’, prayers, sacred imagery, I Ching
The fluxus-inspired event featured classmates Luca (harmonica), Shannon (recorder), Moira (agogo) and Ain (singing bowl).
Instructions such as:
make a sharp sound
make a smooth sound
Play music on your phone (sent individually and to all together)
Stamp and Scuff your shoe
Sing and hold a note (when you hear someone sing a note, join in with the same note after a few seconds)
Ignore this instruction
Squeak a balloon
Drop a balloon over the edge and shout “Balloon!”
Were sent by sms individualy and as a group to performers.
An impromptu installation of a wide stereo diffusion in the Atrium using a cd walkman in random play (with silent tracks of varying lengths) and pc speakers.
Material used was from guitar looping and glitch electronica sessions.
DVD Track listing
I ~ O mighty Reverberacion in thee holie Styrwell of Yternitie!
II ~ Sacred chymings ov thee holie handraile
III ~ Thee goode Sheperd tone
IV ~ Songe of thee Creakinge Door
V ~ Balloon of thee depths Ryse ye up!
VI ~ O moderniste archyetktur of always lystening…
VII ~ In wych disciples of Sounde of thee myriad levels get shutte downe for making too much holy noize..
VIII ~ An message from thee grate Easterne Sage
IX ~ Hall of the great illuzions
X ~ Thee drawinge pyn of temptacion
XI ~ Blessed runnings / Thou who Art on hye
XII ~ Book ov Convolucions
It shows an extended theory behind, nearly impossible to comprehend as is to explain in lines what happens in further dimensions. I wonder if it’s in search of art, if the concept of the process belongs to the final purpose of aesthetics or, if is just an exploration of an idea, a complicated one, which its summum is achieving the process itself of experimentation.