In large organs, such as those in St. Pauls cathedral in London or the Sydney Opera House in Australia, there are literally thousands of pipes. Only a small proportion are visible to the audience - the remainder are kept out of sight. They range from one inch to 32 feet or more in length. Organ pipes in the same organ are made from different materials, depending on the sound quality required.
Tin gives a characteristically bright tone.
For a broader tone, the proportion of tin is reduced and the lead increased, and for a soft tone wood might be the preferred material. A large high-tin organ pipe is made by casting the tin alloy in the form of a sheet just wide enough to form into a pipe of the correct diameter. Very long pipes have to be made in sections which are then joined together. The pitch of the sound produced by the bells is tuned after casting by paring away metal from the inside surface of the bell. Glockenspiels,cymbals and carillons are also made from similar alloys.