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.
1 A vascular tumor such as a glomus may fill the middle ear, or a vein similar to a varicose vein may make enough noise to be heard.  Inner ear disorders that increase hearing sensitivity (such as SCD) can cause pulsatile tinnitus.