Low and Low-keyed

Low adjective - Being near the equator.

Low-keyed and low are semantically related in sounds topic. In some cases you can use "Low-keyed" instead an adjective "Low".

Low-keyed adjective - Restrained in style or quality.

Low and low-keyed are semantically related in quiet topic. You can use "Low" instead an adjective phrase "Low-keyed", if it concerns topics such as sounds.