Justin

Reflection.Process

halfdelta — Wed, 28 Oct 2009 01:32:18 +0000

In the past not taking a step back durring a usual feverish pace of my thaughts and studio deadlines has thrown my process of investigation into concentric loops around my point. To approach the studio this term differently I began recording my thaughts privately through out my process in the last 3 weeks so that I could actually analyze both the project and process of investigation. This keeps my thaughts hidden for a while, but i balieve in the end my thaughts could be better understood if i could react to my process and clearly bring a viewer threw my line of investigation. So in the spirit of reacting to both my process and my investigation, Iwill transcribe my handwritten and typed notes now to bring a viewer through the last 3 weeks of my project. This step back has inexplicably made me calmer, my thaughts clearer going forward and in the end will achieve my objective of being able to reflect on my process thats been muddeled to this stage in Capteur.Emeteur.

Needle.Point.Microphone

halfdelta — Fri, 23 Oct 2009 20:59:15 +0000

Reaction.Drawing

halfdelta — Tue, 20 Oct 2009 17:34:28 +0000

Presenting a drawing for review. In the drawing i specifically tasked myself with looking at the wind currents in the courtyard. Frammed by the membrane of the courtyard. I drew and listend to the recordings of the wind in the space. the currents eddying around mullions and the larger space. The drawing attempts to track the currents and pressures interior to its boundaries. As an open box the currents coming in from the top in a multitude of slight changes in direction was hard to portray. This made the drawing complex and became more an abstraction and hypothesis then a reality of the phenominon of the currents. This reflects more about the scope of the project up until this point as being too large a scope to visually understand to a precision the phenomenon itself. To better understand both a way to draw representationaly with clarity in my work, investigation of a much smaller scope of the membrane is key. I would like to narrow my search to a corner and a few windows along the face of the library. As well id like to employ a smoke generator to investigate plumes with photography to document how the currents of air vibrate and eddie. The smoke i hope will reveal pressure differentials at a manageable scale.

Internet.chatter?

halfdelta — Thu, 15 Oct 2009 03:42:36 +0000

Internet Chatter?

from a linksys broadband router.
http://halfdelta.blogspot.com/2009/10/blog-post.html

Monday.Studio

halfdelta — Mon, 05 Oct 2009 20:35:37 +0000

This post was written as I’m listening to the courtyard. Acting as a narrator of chaotic vibrations. The wire is posted through out the width of the courtyard. It is listening to the tree to the left as it has one leaf resting on the wire. I hope and wonder if the keyboard I’m typing at will be picked up on the contact microphone. HOPE. Posted from Arc01. J.A.R architecture library.

Monday.Studio

halfdelta — Wed, 30 Sep 2009 04:04:01 +0000

Listening to the recordings in studio today, very little was active in the recordings. Of most interests was the vibrations resonating in the alluminum mullion for a period of time after the door would close. In the recordings the immediate interactions with the courtyards membrane where present, a bird hitting the window, a door closing, the shiffting of a chair, or muffled voises from a nearby conversation. The environment in witch the building finds itself begins to becomes present as a character. Then consistently there is some considerable white noise on the recording. A din of mechanical and electrical systems vibrating through a plurality of structural components. These strucutraly born noises, seem to dissapear along with the natural frequencies of the building into the range of white noise when useing the contact microphone.

The pulse of the building seems to “flat line” as its burried in white noise. However, this building abounds with noises as a factory of desks form a programme around the courtyard. Poly cyclical and poly scaler in activity as people continualy move about on different scedules. The Mechanical programe of the building as Patrick pointed out pushes vibration and noise to the outside skin of the building. The J.A.R building domminates the temporality of its immediate perimiter with the vibrations of ducts, exhausts, and human traffic.

A crit with patrick was helpfull. As im trying to question the manifestation of a pulse to the structure it is not dirrectly apparent what im trying to hear. However accousticaly the structural born vibrations are comeing up to the membrane and form a melange of structure, systems, and chaose wich is heard as a white noise. In effect i was worryed about no being able to pick up on a pulse when acctually im discovering a seperate temporality within the larger programe of the building. Akin to an anechoic chamber, the inner membrane of J.A.R transposes a different tomporality of vibrations, and sounds togeather deadining the pulse.

Moving forward will mean developing strategies to trace back sounds to their source and to disect the white noise into components to issolate out a pulse.

Reading.Mechanical and Electrical Equipment for Buildings 10th edition chapter 18

halfdelta — Sun, 27 Sep 2009 19:55:40 +0000

Sound in Enclosure

When the sound is not a continous tone or noise but a series of descrte sounds, following one another and containg information as in speech or music, the room must be designed to maintain and enhance the information intelligibility. That is what is meant by design of the rooms acoustics.

Sound radiates out from a source until it strikes a room boundary or another large surgace. Before reaching the surface the sound intensity is attenuated by distance( the inverse sqare law) and b absorption in the air appreciable above 2000hz.

Absorption.
Coefficient of absorption. Represented the letter alpha( A) defined as A = la/li
la = sound power density (intensity) absorbed by the material w/cm^2.
li = intensity impinging on the material w/cm^2
A = absorption coefficient, with no units since it represents a ratio.

and absorption coeffient of 1.0 indicates 100% absorption and zero reflection of the impinging sound energy.

The total absorption A of a given quanitity of material is proportional to its area and its absorption coeffiecient, that is, A = Sa
where A= total absorption,in sabins. S = surface area, square feet, or square meteres. a = coefficient of absrtion.

a is a ratio. s is a unit of area. Sa should be in units of area as well instad sound absoption units are acllled savin in honor of W.C. sabine, a pioneer in architectural acoustics. One Sabin (m^2) is the sound absorption equivalent of an open window. 1m^2 in area. Similarly 1 sabin(ft^2) is quivalent to 1ft^2 of open window.
As expected 1 sabin(m^2) equals 10.76 sabins(ft^2)

Question.vibration

halfdelta — Sun, 27 Sep 2009 01:59:57 +0000

Vibration and architecture are linked from the moment the foundation
of most any structure is poured. We vibrate out the air bubbles. In
different geographical areas then my own we construct buildings in
such a way to deal with sysmic vibration. Enginneers look at reducing
the vibrations in ducts, vents, floors, stairs. But i wonder what
an architecture that celbrates and presents these vibrations
would look like.

Reading.mechanical and electrical equipment for buildings 10th editition chapter17

halfdelta — Sat, 26 Sep 2009 17:29:04 +0000

Part4.acoustics

Sound is desirable, noise is not. Sound becomes nose when undesired. Air handling devices can mask intuding speach(noise)
Architectural acoustics is simply t enhance desired sound and attenuate noise. Addressing acoustic issues correctly but individually. No unifed theory yet exists.
Chapye 17 (acoustics) descrives types of sounds typicaly encountered in architecure spaces. Frammed as noise criteria (nc) and room criteria (rc) curves.
Chapter 18 room acoustics explanation of absorption and reverberation developing accoustic design criteria. As well a decription of sound reinforcement systems.
Chapter 19 noise control. Absorbive material for room noise control. Devides problem in two airborn noise and strcutre born noises. Relevent criteria in sound transmision class STC and impact sissolation class (icc)

Chapter 17. Regretably leed and systems like it place no points for accroustics. Lighter (greener) materials are poorer . Light structure gernerally transmit more sound. Alluminum architecture is ber poor. (Asside . Jean prouve used apposing bowed metal floor truses to allow floor vibration dampening. Light and strong aswell made of metal and light)
Outside noises can present poroblemes and requie isolation of interior spaces from exterior sounds.

All acoutstic situatiions have three common elements a sound source a sound transmission path or paths and a reciever of the sound.

the listeners reception of sound can be altered but not tiplically architects job.

Sound describes a physical wave a mechanical vibration simple pressure variations in a ellastic medium.

(A) Sound speed of 1130 fps or (344 m/s +-3%)
Sound propegation. The speed of sound is slow enough that it can become a key design issue.
Air 344 M/ps
Water 1410
Wood 3300
Brick 3600
Concrete 3700
Steel 4900
Glass 50000
Aluminum 5800

(b) Wavelength A = c/f Where A = wavelenght in m, C = velocity of sound (m/s), and F = frequencie of sound (HZ)
Sounds within wavelengths 0.5 to 50 ft (12mm to 15 m) can be herd by humans.
Nomograph- wavelength given sound frequency.

(c)Frequency of a sound. # of times a cycle of compression and rarefraction of air occures in a given unit of time. 1000 cycles in 1 second = 1000 cps or 1000 hz.

Pitch is borrowed from music. 100 to 600 hz of fundamental frequencies. with harmonics that reach approximentely 7500 hz.
Accoustic energy exists in lowe frequencies 300 to 4000 hz crictical speach range. Sound of one frequency is called pure tone.

(d) Octave bands. Ration of 2:1 to echother. Center frequences octives fo in 250/root2 or 250*root2
(e) Concepts of sound magnitude. Mesured in loudness, either as sound power level (PWL) or sound pressure level (SPL)
(f) Sound propogation. In air these pressure variations take the form of periodic compressions and rarefactions. Sound is propegated as wavefronts or a longitudinal meachanical wave motion. Radio works longitudinaly bt informations is carried in transvercly in its modulations.

HEARING
If the ear was a magnituted more sensitive it could hear thermal noise.
45 ti 85 decibles and 150hz to 6hz is common hearing range.
MASKING
when 2 sources are percieved simultaneously the perception of each is made more difficult. Technically as number of decivles by witch the threshold of audivility of one sound is raised by the pressence of another sou,d . w frequencies maskes a high frequency better than in the revers. Pink noise refers to the depress low magnitutde infromation haring sounds with higher magnituted low frequencie devices like air diffusers.

In a room low frequencie reachs perimeiter of the room reflects and mizes back to reduce the capacity of human brain to locate souce, it sounds like it is comeing from everyware.) high frequencies- straight line travelling and appears more directional.

SOUND MAGNITUDE

Architectural acoustics encounter.
Three references as absalute measures
Sound power
Sound pressure
Sound intensity

Ratio values that compare an absalute measure to a baseline reference value
Sound power level
Sound pressure level
Sound intensity level

(A) Sound power
Expressed in watts, and dose not varie in its environment or distance to listener.
A jet engine around 100, 000watts, Symphony 10 W, Loud Radio 0.1 W, speech 0.000010 W

(B) Sound Pressure
Sound pressure is the deviation around an ambient air pressure vaused by sound waves. Sound pressure is influenced by the nature of the environment between the source and the reciever. This includeds the distance between source and reciever. Sound pressure is express in Pascals (Pa)or micro bars in the I-P ststem. SI units for all architectural acoustics metrics is common. 200 Pa near a jet plain. threshold of pain 20 Pa, loud nightclub, 2 pa. next to a highway, 0.2 pa. normal speech is around 0.02 Pa.

(C) The threshold of hearins is the minimum sound intensity (i), 0.0000000000000001 w/cm^2. The maximum sound intensity a human ear can accept withought damage is approcimetely 0.001 w/cm^2. The sound intensity at any define distance fom te source is expressed as i = p/a where i = sound(power) intensity, w/cm^2. P = acoustic power, w. A = area, cm^2. Since sound radiates freely in all directions. i = (p / (4 x (pie) r^2 )) X w/cm^2

Sound emmits in a sphere, so here the formula uses inverse square law, a law which states that intensity is inversly proportional to the square of the distance from the source.

SI data is expressed in M so a conversion from cm^2 to M^2 is necessary.
(http://joshmadison.com/software/convert-for-windows/)
- Great Conversion software. Light Simple Fast.

Note.
A small point source produces waves larger then itself, and emits spherical waves.
A Line source such as strings produce cylindrical waes. Lare vibrating surfaces such as walls, produce planer waves.

Reading.handmade electronic music

halfdelta — Sat, 26 Sep 2009 17:16:58 +0000

the art of hardware hacking.written by Nicolas Collins

My objective in reading this material will be to expand apon my own ideas about how new sounds are played back and how they can effect the recording, producing new sounds as a result.

[Shopping List]
Tools:
Weller Soldering Iron.
Solder: Fine rosin core, not flux-core
Side Cutters, Needle Nose Pliers, Tweezers
WireStrippers
Jewlers Screwdrivers
Scissors
Multimeter: (resistance, voltage, current)
Electrical Tape
A third hand.

Parts:
22-24 guage wire, 1 roll stranded, 1 roll solid-core
Shielded audio hookup cable, single conductor plus shielded
Resistors 1/8 – 1/4 watt
Capictors, 10pf to .1uf monolithic ceramic or metal film and 1uf to 47uf electrolytic
Nine volt battery terminal clips
Assorted audio jacks

part2.listening

Listening with a radio: the radio coil can pick up on electromagnetic waves, and drop the frequencie down to where the human ear can percieve it. The Interesting thing to me, an FM radio can pick up the periodic signal of the clock frequency of a computer.

Listening with a coil: Copper wire spun around a iron slug will produce a similar effect as a the radio, also good to pin point the sounds of low frequencie electromagnetic waves. Also the coil is good for listening and recording that witch is being emited from a voice coil on a speaker. This will cause interference as the mic approaches the monitor. The pitch is determined by the distance between the two devices.

Cults:
The Length of a wire used in the coild affects its sensitivity to different frequencies. VLF (very low frequency), can be interecepted with a large wooden corsses and wrapped in yards of wire. (the Guide) suggests two 5foot pieces of 1 x2 nailled togeahter. “Plug in, Turn on, Drop out”
Excaping the 60/50 hz hum of modern society is key.