By Nicolas E.
For each asteroid or comet on the file, we extracted some common characteristics to set the sound parameters. The most important aspect is to portray how often they pass near the Earth, so the representation of the time has to be accurate. We set an equivalence of one month = 5 seconds and a year multiplier of 12 months, in case we wanted to make a longer year to introduce longer periods of silence on the score. The audio file starts on Jan 1, 2010 - the earliest year from the acquired data set. Each rock's discovery date sets its first occurrence on the score, and each occurrence repeats itself according to its period_yr (except for the 'Parabolic Comet', which doesn't have a return period).
month_interval = 5. # in sec
year_mult = 12 # multiplier (how many months in a year)
for a in aster_data:
# get raw data
datetime = dateparser.parse(a['discovery_date'])
yea = datetime.year # starting time
mon = datetime.month # starting time
day = datetime.day # starting time
# first occurrence (starting in 2010)
start = ((yea-2010)*year_mult + mon + day/30.) * month_interval
start += recur *year_mult
For the other parameters, we selected characteristics that gave us some expressive possibilities. The pitch of each rock is based on the orbit's angle (i_deg), the instruments are based on the orbit_class, the duration on the q_au_1 (which we have no idea what it actually represents). For the scale of this score, we chose a minor B flat, in reference to the sound of a black hole and the "lowest note in the universe".
by Katya R.
The first three corresponded to the three most common occurring meteors and asteroids. These are subtle "pluck" sounds. A pluck in CSound produces naturally decaying plucked string sounds.
The last six instruments consisted of louder, higher frequency styles.
Instrument four is a simple oscillator.
Instrument five, six, and eight are VCO, analog modeled oscillators, with a sawtooth frequency waveform.
Instrument seven is a VCO with a square frequency waveform.
Instrument nine is a VCO with a triangle frequency waveform.
linseg is an attribute we used to add some vibrato to instruments 6 - 9. It traces a series of line segments between specified points. These units generate control or audio signals whose values can pass through 2 or more specified points.
Each instrument's a-rate takes variables p4, p5, and p6, (which we set to frequency, amplitude, and pan) that correspond to values found in the JSON file under each instance of a meteor/asteroid near Earth. The result is a series of plucking sounds with intermittent louder and higher frequency sounds with some vibrato. The former represent to the more common smaller meteors and asteroids and the latter represent the rare asteroid and meteor types.