Congas, being percussive instruments, do not have to be tuned to any particular note in purely percussive settings. They are tunable to different notes. However, when playing with harmonic instruments, they may be tuned to specific notes. Generally congas are tuned using the open tone. The original drums were tuned by adjusting knots and tension ropes on the drumhead, or, where the drumheads were tacked or nailed to the top of the shell, by careful heating of the head. Modern congas use a screw-and-lug, tension head system that makes them easier to tune (or detune).
Terminology for the drums varies. The naming system used typically follows those currently in use by major conga manufacturers. The drums are discussed in order from largest to smallest; the sizes of the drumheads slightly vary by manufacturer, model, and style:
The supertumba can be as large as 14 inches across (35.5 cm).
The tumba is typically 12 to 12.5 inches across (30.5 to 31.8 cm).
The conga is typically 11.5 to 12 inches across (29.2 to 30.5 cm).
The quinto is typically around 11 inches across (about 28 cm).
The requinto can be smaller than 10 inches across (24.8 cm).
The ricardo can be as small as 9 inches across (22.9 cm). Since this drum is typically played while hanging from a shoulder strap, it is considerably shorter and narrower than a traditional conga.
In general, the particular note will depend on the make, model, and size of the conga drum. The drum should be tuned so that the bass tone resonates; the open tone rings, and the slaps pierce through the musical mix. If the tuning is too loose, the bass and slap tones will sound "flabby"; too tight, and the drums will sound unnatural and "pinched." With a single drum, it is difficult to go wrong with tightening the drum until it makes a pleasing sound. When two or more drums are used, however, there is much variation on which two notes are chosen. With two drums, it is not unusual to find them tuned a perfect fourth apart.