Homework 1

For this assignment, I decided to go back to my British roots and sonify London's GDP from 1830 to 2009, as well as the percentage growth year on year. You can find the data at these links:

I played around with the Mandolin unit generator in Chuck, generating a 'mandola' sound by increasing the body size of the instrument. There is also a fair degree of echo. I decided to map the data values to an octatonic scale. I scaled the values so that they fell between 0 and 1, multiplied them by the number of tones in the octatonic scale, and rounded them down to equate the values to a pitch class. Then I transposed them to start on B-flat in a reasonable octave for a mandola. Since the options for duration are chosen at random, each channel finishes at a different time, with growth (right channel) stopping before the GDP (left channel).

Here is a link to my .wav file:

Here is my code:

I ended up not using the update rate or the gain function built into the Duo player, but with regard to the questions:

1. I'm not 100% sure about this one, but squaring the gain values would decrease the values (since they are less than 1). You would probably get distortion if you didn't do this and you were running multiple threads at once. Will update this field once I'm sure...

UPDATE: squaring the gains attenuates the lower gain values more than the higher values. Loudness/intensity is not perceived linearly (it is a logarithmic scale), so from a psychoacoustic perspective, squaring the gains maps better onto our perception.

2. MIDI keynums are mapped linearly to pitches, while frequency is a logarithmic scale. Hence, by mapping to MIDI keynum, you get a greater degree of pitch fluctuation, which represents the time series more faithfully. Otherwise you barely hear the pitch change.

3. Increasing the update time decreases the tempo of playback, while decreasing it increases the tempo.