1 Pixel density: Pixel density-The pixel density of a display represents the number of pixels over an area of one inch. 2  Itâs measured in âpixels per inchâ, or ppi.
Eustachian Tube Dysfunction can be caused by large adenoids, allergies, or a cold. This dysfunction can cause crackling or popping noises in our ears. The tube is lined with moist mucosa, and inflamed Eustachian tubes often get sticky, which causes the crackling and popping noises when the tubes are moving around. If the inflammation is serious, it can be easily treated with steroid nasal sprays.
Crackles can be caused by pneumonia, pulmonary edema, pulmonary fibrosis, and acute bronchitis. Shortness of breath or trouble catching your breath with or without exertion. Stridor, a high-pitched sound made during breathing, often caused by some kind of blockage in the throat.