The availability of electricity opened the way for these marvelous devices, and many existing bell towers were equipped with electric bell ringers. A group of two to eight bells, tuned to a particular scale or chord, is called a peal of bells. The three bell peal is the most popular, with the six bell peal next in popularity. These are swinging bells, each having its own natural rhythm which is determined by its size and weight. A continuously changing pattern of harmonious sounds is created.
Most peals use a major chord of at least the first, third and fifth notes.
Today, fixed bells can be equipped with electric bell ringers, which are then wired to a keyboard for manual playing, or interfaced with a new electronic carillon control system to strike at the same rate as a swinging bell of the same size. This imitates a peal of swinging bells very well. However, if you've ever listened closely to a swinging bell, you discerned a slight difference in tone between the two sides of the bell when struck. This difference is lost when the electric bell ringer is used because it strikes exactly the same spot every time. The I.T. Verdin Co. tried to create a more realistic effect by alternating the pressure of the strike from loud to soft each time.