:: GussetBLOG ::

:: Thursday, December 10, 2009 ::

Colo[u]rs of Noise

I came across the term “green noise” recently. White, Pink and Brown(ian) noise have strict mathematical definitions that I am well aware of, but there's a whole spectrum of other definitions out there, some more flexible than others. The wikipedia page is worth a read.

For example:

• Blue noise seems to be a term used in graphics dithering,
  
• A-weighted pink noise becomes Grey noise.
  
• Bands of zero energy are centered about the frequencies of musical notes in whatever scale is of interest. Since all in-tune musical notes are eliminated, the remaining spectrum could be said to consist of sour, citrus, or "Orange" notes.
  
• "Green noise is supposedly the background noise of the world. A really long term power spectrum averaged over several outdoor sites. Rather like pink noise with a hump added around 500 Hz."

I want to hear me some orange noise.
This green noise definition is interesting. I would have expected it to more closely resemble traffic noise (see fig below), but maybe that's because I live in a city. I’m going to look into this more as I survey noise levels all over the place anyway.


Normalized road traffic noise spectrum figure, from BS8233:1999

Labels: Acoustics, Maths

:: Dan 10.12.09 [Arc] [0 comments] ::
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"A student collapsed at a freshers’ party and died after complaining the loud bass music was ‘getting to his heart’, an inquest heard yesterday," reports the Metro. Deeper in the text you find, "A coroner recorded a verdict of natural causes, saying the straight-As student was killed by sudden arrhythmic death syndrome (SADS), a heart disorder which kills 12 young people a week. Cardiac experts said the bass could have triggered SADS if Mr Reid had underlying, yet unknown, genetic problems."

Labels: Acoustics, health

:: Dan 9.12.09 [Arc] [0 comments] ::
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Positive use of sound is a hot topic in acoustics at the moment. I attended the Institute of Acoustics conference on Soundscapes at RIBA HQ last year. The day was intended to ignite some debate over a single controversial sentence that may or may not make it into the final version of the governments Planning Policy Statement 24: Noise (PPS24) when it's finally published. The issue at hand was whether all noise is bad noise and the lower the background noise is the better, the old view as espoused by the current Planning Policy Guidance 24: Noise (PPG24).

You'd think this was a stupid point, but within the field it's a difficult one to address. The danger is that if you say that some masking noise may be good to help drown out another more annoying noise where do you stop? And how long will it be before every developer just plonks a water feature in the middle of every development?

The importance of the debate was nicely set-up by RIBA President Sunand Prasad, of Penoyre & Prasad Architects. He has a keen understanding of acoustics beyond that of an add on service as it is seen by many in architects. It was great to get involved in the debate as opinion is hotly divided between the "experts" probably as much as it would be between random people asked on the street.

As an musician / artist as well as an acoustic consultant I love the idea of using ambient sounds to enhance an environment. It's like taking what Eno did with Music for Airports to a new level. Music for Housing Estates. Or even Music for Cities.

With this in mind it was interesting to come across Mark Bain's Sonic Architecture (Sonarchitecture) essay, referenced in the BLDG Blog book. The text (Word doc) is here.
From Earshot No 3, Journal of Soundscape, Nov 2002, UK

The website and some photos from the Tunes City - Symposium and more from Google

The City of Sound website is also well worth a browse.

Labels: Acoustics, architecture, Sound

:: Dan 8.8.09 [Arc] [0 comments] ::
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Recycled cardboard speakers, a must have for the world wary self-conscious hipster.

It was also pointed out to me, after making my cardboard pinhole camera from Magma, that Urban Outfitters also sale them, although not the same model. They have a nice range of Lomos and related goodies too.

But somehow it rankles with me how stylishly it's all dressed up.

Labels: Acoustics, Environment, Fashion, Photography

:: Dan 27.5.09 [Arc] [0 comments] ::
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"We experience spaces not only by seeing but also by listening. We can navigate a room in the dark, and "hear" the emptiness of a house without furniture. Our experience of music in a concert hall depends on whether we sit in the front row or under the balcony. The unique acoustics of religious spaces acquire symbolic meaning. Social relationships are strongly influenced by the way that space changes sound. In Spaces Speak, Are You Listening? Experiencing Aural Architecture, Barry Blesser and Linda-Ruth Salter examine auditory spatial awareness: experiencing space by attentive listening. Every environment has an aural architecture."



"Eusebio Sempere, a respected minimalist 20th century Spanish artist, created a sculpture composed of a three-dimensional array of polished stainless-steel tubes that rotates at its base, as shown in figure [above]. In addition to its provocative visual effect as the moving surfaces reflect in the sunlight, it was also a sonic filter that blocked transmission of particular frequencies. A listener on one side heard a tonal modification of those sound sources located on the other side, the visual equivalent of colored glass prisms. This sculpture is an aural embellishment because it changes sounds that propagate through it."



As referenced in Trevor Cox's Sound Architecture: Spaces That Speak programme on Radio 4 last week, unfortunately no longer availble on the iPlayer. (Although I do have an MP3 rip. Get in touch if you really want to hear it.)

Labels: Acoustics, Literature, Radio4

:: Dan 24.3.09 [Arc] [0 comments] ::
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Sometimes I have to measure the Reverberation Time in a space. In large spaces sometimes a starting pistol is required, as here. Sometimes this leaves residue of explosives on my clothes or my testing equipment. I then get stopped by airport security in Belfast or at the Eurostar terminal because I've tested positive for explosives and have a lot of explaining to do.

Sometimes, in smaller rooms, popping a balloon is good enough. This means I have to go and buy balloons from an old woman who is suspicious I am going to use them for selling nitrous [oxide] at "raves."

With a memory as bad as mine I have to write a note on my hand before I go out for lunch to remind me to buy balloons. Today I choose to draw a small picture of a balloon as it would be more subtle than writing the word.

When I draw a small sketch like that one of these two thoughts commonly result:
1. Not bad, I should sketch little things like that more often, it's strangely satisfying.
2. Fuck. I've just drawn a sperm on the back of my hand.

Today was one of the latter.

Labels: Acoustics, Flickr, Humour, Photography, Travel

:: Dan 10.2.09 [Arc] [2 comments] ::
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The world's most powerful loudspeaker, the WAS-3000, at Wyle Laboratories acoustic test facility.

"The WAS-3000 is no spring chicken. It was built back in 1967 and remains, as far as anyone knows, the most powerful loudspeaker ever built, able to generate sound pressure levels up to 165 dB with just a single modulator. No, it wasn't designed to blast Buffalo Springfield or Procol Harum (which would not sound like music at all at that level), but rather to do acoustic wave testing on equipment via a "linearly controllable electro-pneumatic noise source." (What would you test with such a speaker? In part, it's been used to test whether jet engines and space shuttle components will fall apart when exposed to extreme noise and the vibrations that go along with them. It was built originally to simulate noise from the Saturn V launch.)" [yahoo]



A space shuttle taking off generates 150 dB. It is more than loud. It is outright dangerous. "That large bath of water coming down the side of the main engine when it launches is not for cooling, which is what most people think," explains Rich McKinley, an acoustics expert at Wright-Patterson Air Force Base near Dayton, Ohio. "It is to break up the acoustic waves so they don't damage the shuttle." [Popular Mechanics]

Labels: Acoustics, Noise, Physics

:: Dan 20.10.08 [Arc] [0 comments] ::
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"A slight difference in the sounds created by neutrons and alpha particles as they travel through a liquid could lead to the first direct detection of dark matter, say physicists working on the PICASSO experiment at SNOLAB in Canada."

Labels: Acoustics, Physics

:: Dan 17.10.08 [Arc] [0 comments] ::
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Clive Thompson on How Man-Made Noise May Be Altering Earth's Ecology

Bernie Krause listens to nature for a living. The 69-year-old is a field recording scientist: He heads into the wilderness to document the noises made by native fauna — crickets chirping in the Amazon rain forest, frogs croaking in the Australian outback.

But Krause has noticed something alarming. The natural sound of the world is vanishing. He'll be deep inside the Amazon, recording that cricket, but when he listens carefully he also hears machinery: The distant howl of a 747 or the dull roar of a Hummer miles way.

Krause has a word for the pristine acoustics of nature: biophony. It's what the world sounds like in the absence of humans. But in 40 percent of the locations where Krause has recorded over the past 40 years, human-generated noise has infiltrated the wilderness. "It's getting harder and harder to find places that aren't contaminated," he says.

This isn't just a matter of aesthetics. The contamination of biophony may soon become a serious environmental issue — Krause says that man-made sounds are already wreaking havoc with animal communication. We worry about the carbon emissions from SUVs and airplanes; maybe we should be equally concerned about the racket they cause. ...

Labels: Acoustics, Ecology, Noise

:: Dan 30.5.08 [Arc] [0 comments] ::
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HPS
Originally uploaded by gusset.

Holland Park, London, at sunset, from the roof of Holland Park School. Noise survey in progress.

My ex-colleague klem@s has taken a break from stalking random women around London to create an Acoustic Engineering flickr pool. I've used it as an excuse to upload a bunch of site photos I've previously not had reason to, like the above.

Labels: Acoustics, Flickr

:: Dan 25.5.08 [Arc] [0 comments] ::
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Space as a Symphony of Turning Off Sounds
[via bldg blog]

Or alternative title, 'Artist has no idea about basic acoustics and designs stupid toy that will never work'

Labels: Acoustics

:: Dan 29.4.08 [Arc] [0 comments] ::
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"We’re not just talking typical city noise," the article says, "but what scientists here say is more like living inside a factory."

Bldg Blog on noise in Cairo

"Provided I can ever get my act together on this, I've got a long and totally fascinating interview with Jace Clayton, aka DJ /rupture, coming up here on the blog, in which we discuss the sonic qualities of cities, focusing on New York and arriving there via Marrakech, Barcelona, and even Rennes, France."

That sounds really interesting. You can, incedntally, hear DJ/Rupture's appearnce on the Goatlab Radio show here:
GoatLab Radio with Parasite and special guest DJ/Rupture - October 2007

Bldg Blog continues, "I'm tempted to organize something called World Noise Day*. Make your city as loud as possible. Take advantage of car horns, personal stereos, supermarket broadcast systems, and the local radio. Play Merzbow† all day, cruising loops in boom cars. Rebuild Luigi Russolo's intonarumori. Install Japanese war tubas and British sound mirrors throughout the city. Turn on hair dryers. Yodel. Record the sounds of noise in the morning – and play them again that night, much louder."

* Of course our friend Shitmat already runs an annual National Noise Day here in the UK.
† And coincidentally I have a gig with Merzbow on Friday! He's playing at the Croft just before Goatlab starts (thanks to some strange booking thing I won't go into).
Look like the UK is one step ahead here.

Labels: Acoustics, architecture, Noise

:: Dan 16.4.08 [Arc] [0 comments] ::
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Oobject's Guide to Anechoic Chamber Architecture
"In this kind of space, no one can hear you scream. Anechoic chambers use spiked walls to eliminate echoes, the end result might literally sound dull but the visual effect can be stunning, such as at the enormous anechoic hangar. Vote for your faves."

[via Music Thing]

"There is nothing not to love at Oobject's Guide to Anechoic Chamber Architecture. Above is AFJ International's tank-sized chamber, and the Auditory Localization Facility is a person-sized loudspeaker-filled geodesic sphere packing a generous punch of awesome. Less high-minded readers might also enjoy Nick Knight's rather splendid fashion/audio crossover The Sound of Clothes, which includes several not entirely SFW videos."

Labels: Acoustics, architecture, Fashion

:: Dan 15.3.08 [Arc] [0 comments] ::
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Noise more important than environment says NAT

Labels: Acoustics, Environment, News, Noise, Politics

:: Dan 21.2.08 [Arc] [0 comments] ::
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'Cloak of silence' design is unveiled
Two independent teams of researchers have come up with a recipe for making special materials that could completely cloak an object from sound. Although the “acoustic metamaterials” have yet to be made, a third team is now trying to create a real cloak. These metamaterials promise to guide sound waves around an enshrouded object as if the object wasn’t there. As well as being used to conceal submarines from detection by sonar, such metamaterials could be used to improve the acoustics in concert halls.

Pope calls off university visit
The protests of nearly 70 scientists, including former CERN director general Luciano Maiani, have forced Pope Benedict XVI to cancel tomorrow’s visit to La Sapienza University in Rome. The scientists, who expressed their objections in a joint letter to the university’s rector earlier this week, deemed the visit would be “incongruous” with the Pope’s previous support of the persecution of Galileo in the 17th century.

Labels: Acoustics, Physics, Religion

:: Dan 18.1.08 [Arc] [1 comments] ::
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If Its Hip Its Here: Speaker Manufacturers Turn Up The Volume On Design

Example: The B&W Nautilus

Labels: Acoustics, Design, Hi-Fi

:: Dan 17.1.08 [Arc] [0 comments] ::
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Noise might cause huge ocean waves - physicsworld.com
"Every so often mariners report the sighting of a huge wave towering up to 30 m above the regular swells of the ocean surface. No one is sure why these rogue waves form, but now physicists in the US and Germany have managed to produce equivalent optical rogue waves by launching laser pulses into photonic-crystal fibres. Having performed computer simulations of the optical system, the researchers suggest that optical rogue waves, and therefore oceanic rogue waves, are seeded by noise."

Labels: Acoustics, Physics

:: Dan 21.12.07 [Arc] [0 comments] ::
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'This is our world: the acoustics of vegetables'
The Vienna Vegetable Orchestra serves up a musical feast at the Huddersfield Contemporary Music Festival
[via grom]

Labels: Acoustics, Food, Music, Video

:: Dan 18.12.07 [Arc] [0 comments] ::
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I mentioned Trevor Cox's new acoustics programme on Radio 4 last week. If you missed it you can listen again here: The Sounds of Science.
[13MB MP3 from podcast]
The second (and final) programme is on tonight at 9pm GMT.

Labels: Acoustics, Radio4, science

:: Dan 31.10.07 [Arc] [0 comments] ::
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Iannis Xenakis: Phillips Pavilion, Poème Electronique, Edgard Varèse [Brussels 1958]
I've read a lot about, and listened to a lot of, Xenakis’s music, so it's interesting to see something pop up about his architecture now and again. Especially when it was designed as a specific audio/visual display space.

Labels: Acoustics, architecture, Art, Visuals

:: Dan 24.10.07 [Arc] [0 comments] ::
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