Unit 2 Lab 3: Make Some Noise, Activity 5

pick random (1.2.2)
/ (1.5.1, where it's introduced and 1.7.6, where they use it to build average)
length of list (1.7.5)
(sample rate) of sound (2.1.1?)
play sound (2.1.1)
repeat (2.1.1)
for each (2.1.2)
show/hide variable (2.1.3?)
set variable (2.1.3?)
global vars (with generator?)
warp (with generator)
add (?)

Sound is pressure waves, and the patterns of those waves determine what the sound sounds like. In Snap!, sounds can be generated as lists of volume intensities. You'll start by creating one second of "noise", which is just random intensities that sound like static.

Making Noise

Open your "Sparks-Making-Noise" project if isn't open already.
Create a variable called noise to store the intensity values, and make it start as an empty list.
What is the difference between the inputs of the following two expressions? What is the difference between their outputs?
What will this code do?

Look at the variable watcher on the Snap! stage to confirm. Drag its corner to expand, and then scroll.

Click for a break-down of how this code works.

The above code repeatedly adds a random number between -1 and 1 to the noise variable.
The first input to pick random is -0.99999 instead of -1 to force that block to output decimals rather than only integers.
The add block is repeated sampling rate number of times.
The warp block acts like a time-warp to speed things up.

The sample rate is how many intensity samples fit in one second of sound samples detected by the microphone.
(sample rate) of sound (microphone(samples)) reporting 44100

Build that code in Snap!, then drag the noise variable into the play block, turn down the volume, and play the noise. Debug your code if needed.