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.
Tinnitus: people with tinnitus hear a constant ringing or roaring sound. The cause of this ringing cannot always be found. Some cases of tinnitus are caused by ear wax, ear infections or a reaction to antibiotics, but there are many other possible causes of this disorder.