Music 171 homework 2
This assignment is to make a movie-soundtrack-style foghorn sound.
Your successful patch should sound like
To make the patch:
- Using a phasor~ and a table lookup (non-interpolating), make a signal
that switches between 70.7 and 50 (for example. That ratio is about the square
root or 2, which makes a musical tritone), going between the two with an
overall period of 5 seconds. (The table only needs two values in it. The
phasor~ output should be adjusted to have a range from 0 to 2.)
- Using that as the frequency for a second phasor~ object, and adjust that
phasor's range to 1 to 301 (for example if it's a 303-point table), and use
that as an index to a second
table that holds an audio waveform. You can draw the waveform by hand and/or
record something into it.
- Make a second frequency signal about 1/3 Hz. higher (just add the value
to the output of the frequency table), and use it as the frequency for a second
audio waveform lookup similar to the previous one.
- Add the two detuned audio waveforms and apply an amplitude control to
the sum to allow turning the sound on and off. Make separate message boxes to
turn the output sound on and off. When 'ON' the amplitude should
be reasonable (say in the range 0.1 to 0.2).
- Test it to see that when you re-start Pd and reload the
patch, all you have to do to hear the sound is turn on DSP and to click the
"on" message box.
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