RM/AM/FM Synthesis

FM: Squelchy sound made with a modulation ratio of 1/7.

(sound)

(image)

FM: Interesting overtone sort-of descending melody, when carrier wave is at 492, modulator ratio is 266/40, and the modulator amplitude envelope peaks after the main amplitude envelope

with 492: (sound)

with 391: (sound)

(image)

Ring Mod: Carrier and modulator reversing frequencies (from 100 to 400hz).

(sound)

(image)

Tuning sketches

Drawing on your additive synthesis work from the last class, experiment with different just intonation or equal temperament intervals and scales.

A major third (using three sine waves, at 150, 200 and 300hz) played first in just intonation, then in equal temperament. (listen)

0-5 scale in 12 tone equal temperament. (listen)

0-5 scale (using major third) in 6 tone equal temperament. (listen)

same, in 24 tone. (listen)

My patches:

Tonechanger.

Toneadder.

From JHNO: “Lattice” – (patch)(source page)

Additive Synthesis sketches

Create 10 sketches by combining sine waves. Control the sine waves over time to achieve timbral changes.

1. 30HZ rising in amplitude while 60HZ falls. (listen)

2. Same as 1, accompanied by 40Hz rising and 80 falling in amplitude. (listen)

3. Using 6 partials, at only odd-numbered (inharmonic?) frequencies. (listen)

4. Same, using even-numbered frequencies. (listen)

5. Using amplitudes that peak at concurrent times, we hear a range of frequencies, from 10 – 60, in 200ms. (listen)

MMS “Reverse Image-Labeller”

For this mini-project, I worked with Mobile Media classmates Yaminie and Thomas to develop what Yaminie-termed the “Reverse Image-Labeller” (the inversion of Google’s Image Labeler) – instead of requesting people to tag existing photos, they would be supplied with a keyword, and take mobile phone pictures that fit that description (so, to use a non-negative definition, i guess it’s a kind of image-hunt game). The results, so far, are a rather bare-bones site, accessible here. Possible future additions: comments, voting.

Interactive Sound – Wave experiments

Find and use waves to generate sound. Basic oscillations in Max/MSP can be generated with the ~cycle object – which other ones can you find or develop? Push your waves into the extreme time and level domains discussed in the Roads reading (also note how the digital domain works with and against you in doing so).

Two sinusoidal waves added together, one at frequency 200, the other at 100 – listen

The same two, multiplied – listen

Sinusoidal wave at 200Hz added to one at 208Hz, point where rhythmic effect appears – listen

Two sine waves at 200Hz, the one informing the phase of the other (improperly recorded) – listen

Sine wave at 200Hz, phased from 0 to 1 over 70(ms?), looped, multiplied to unchanged 200Hz sine wave. – listen

I’ll Send an SMS to the World

And that’s the last time I’ll ever allude to the Police on the blog. Some SMS projects I like:

Canal Accessible is an online photographic directory of the places around Barcelona that make like difficult for the physically disabled. The obstacle or impediment is photographed with a cellphone camera, and uploaded to the website. It’s an interesting way of imaging the city from a unique perspective, and an good example of how the immediacy of the mobile camera lets us document places and moments that would’ve likely been ignored in the pre-mobile era.

Both TXTual Healing and Urballoon use projection technology to writ large the usually small and personal Short Message. “TXTual” does this by placing SMS conversations into ’speech bubbles’, usually projected onto screens and buildings. It turns the usually inward, introverted activity of SMSing into an engagement with public space, and an acknowledgment of a larger public conversation. Similarly, “Urballoon” (a big, tethered ball that floats around 3 stories high) projects SMS messages onto the ground, from a great height. These projects have the effect of making a small action into something epic, and opening up the language of ‘txt’ into something potentially broader, perhaps more political (both project websites emphatically emphasize their commitment to free, uncensored speech).

Finally, a little self promotion – midway through 2007 I initiated a project called Tree ID, which encouraged fellow South Africans to find the cellphone towers in their area that had been disguised as trees (this is a common activity – I have since been assured that there are over a thousand) (though I got a grand total of five submissions), photograph them with their mobile cameras and send them to a number. They would then be forwarded to an online database, and ultimately place them on a Google Maps mashup, based on their location (gathered through a triangulation of cellular towers). With this, I wanted to ask people (in a fairly humourous way) to examine the intersections between society, technology, and the ‘natural’ environment, thinking of the cellphone tower as one of the few visible (though often obscured) markers of a largely invisible process of electronic information exchange.

Interactive Sound: Listening Exercises

Careful listening. Step 1 – listen out. Listen first to sounds near you, then proceed outward to the edge of your perception, attempting to hear sounds from as far away as possible. Step 2 – listen down. Find a repeatable sound, like footsteps, a keystroke on a keyboard, etc. Listen as closely as possible to this sound, attempting to perceive the sound not as a singular sonic “icon” but as a complex phenomenon with many components.

Listening Out:

I can feel the pressure of the wind on my ears, I hear a kind of ‘low frequency’ hum, or rumble. There are ‘soft’ scraping sounds, punctuated by short, piercing high frequencies, like ‘pin pricks’, all moving left to right. From my left ear, a low growl or murmur, with an irregular tinkle. Trying to listen ‘out’, it’s hard to tell if the wind is the closest or the furthest sound I’m hearing – between some sharp shrieks and sudden, rounded tones, there is a slowly modulating, constant, quiet wail. There are pieces of conversation occuring, in varying tones, they are extremely hard not to hear as language. Traffic noises still produce a moment of recognization, ‘icon-ification’. Very brief sharp tones in quick succession, little pulses.

Listening In:

Two tones, one higher than the next, almost a compressed melody. One sharp tone, followed by quick reverberations, occurring first as a singular sound, then separating out over time into discrete sounds, while decreasing in volume. (sample).

The Serial + Code Bits

“Pathways” uses Processing to receive the serial values sent by the Arduino microcontroller, and uses those values to switch between a number of pre-rendered images. There are two images that related to every point on the map/body, and inserting the needle displays one of the these two images (using a randomly chosen number that is generated as you poke). Programming-wise, “Pathways” is ‘just’ a dynamic image gallery, though perhaps in use it often seems more complex than it really is. Because these images (rendered in Flash and further treated in Photoshop) contain so much information specific to your action (ie. the location on the map where you’ve inserted the needle, the name and image associated with that same point), it seems that the separate interface components are being calculated and ‘drawn’ on-the-fly, rather than just selecting one of a range of pre-existing images.

Though our solution isn’t especially object-oriented (ie. versatile, easily extended, modular), it really seemed like our best option. Initially, we planned to animated the line connecting the points – in Processing, this would have involved either hard-coding a number of interstitial points, and writing some code to draw lines between those points, or running some kind of colour/blob detection to work out the shape of the map lines (which would probably have fairly limited accuracy). This drove us to Flash, and while we didnt end up animating, Flash really allowed us to build the kind of textured, visually rich interface that we wanted.

Finally, the code is available here.

The lost labs…

For completeness’s sake (and continuity’s loss), here are some bits from labs I didn’t document:

Early days -  analogue to analogue input (potentiometer controls LED):

Experimenting with servos – this was actually part of an abandoned midterm idea (the printer foosball notion, perhaps it’ll still be realized one day), but it’s more entertaining than my lab. A servo responding to colour tracking:

What came next..

The rest of the acupuncture project was documented at zangfu.wordpress.com, but I wanted to use this blog to discuss some of the technical issues in further detail.

Basically, we wanted to create a system where an ‘ordinary’ acupuncture needle could trigger a switch – we needed something that would be soft and reusable. Thomas Gerhardt was working on something similar – a felt resistor – and suggested using steel wool. This proved fruitful – we eventually constructed a series of ‘cartridges’ containing two bundles of steel wool, separated by a layer of rubber. The one bundle was hooked up to power, the other to ground, and when the needle penetrated both, the circuit was completed.

A problem: steel wool ignites when you put 5 volts or higher near it, so we had to restrict our power input to 3v (easily done with the Arduino Diecimila, where you can set output to 3v, but we stuck a regulator on the board too, for peace of mind).

A bigger problem: the needle sometimes takes bits of steel wool with it when we’re poking around, creating a situation where the two wool bits are permanently connected. After trying extra layers of glue, packing the steel wool in latex, we eventually came upon the most effective (and seemingly most obvious) solution – adding extra rubber. As of writing, this works. Some pics:

And here’s our initial ‘aha’ moment with the steel wool (sorry for the lousy lighting):