Vumeters are graphics showing the input of volume using the "loudness" command. Scratch can manage it to make nice animations.
Scratch does not allow distinction between bass, midrange and treble but at least measure the volume of sound coming from the microphone, which offers us nice perspectives to create vumeters by using the pen commands of Scratch. I also used it to make the background's games disappear or create game controls, forcing the children to use the ambient noise in a rather bizarre way to achieve their goal.
The technique for these vumeters is simple. The volume's input is stocked in a variable, then I subtract this value from the height of the screen (360 pixels) divided by two, in order to center the drawing. We draw a first line, then a second line of the volume value (multiplied by a factor X to manage the sensitivity of the microphone) and finally a third to the top of the screen and we start two pixels farther to the right. The color effect is obtained by changing the color of the pencil. Once the pen get to the right edge of the screen, you go back and so on.
The second one is simpler and merely draws a line of the height of the volume.
Rainbow wave vumeter : https://scratch.mit.edu/projects/146679599/
Simple vumeter : https://scratch.mit.edu/projects/146813970/