| A | B |
|---|
| Infrasonic | Frequency too low to be heard by most humans |
| Ultrasonic | Frequency too high to be heard by most humans |
| Compression | High density region of the medium |
| Interference | Superposing different waves |
| Beats | Alternate reinforcments and cancellations produced by interference |
| Diffraction | Bending of waves around small obstacles and openings |
| Refraction | Bending of waves due to density differences in the mediums |
| Doppler effect | Apparent shift in frequency due to relative motion |
