These crackles were recorded over the right
posterior lower chest of a 9 year old boy with pneumonia.
provides a visual representation of the content of the respiratory sound
recording. Time is shown on the horizontal and frequency on the vertical
axis. Sound intensity is indicated on a color scale, ranging from red (loud)
over yellow and light green (medium) to dark green and gray (low). Calibrated
air flow is displayed at the top (I = inspiration, above zero; E = expiration,