The most common oboe plays in the treble or soprano range. Oboes are usually made of wood, but there are also oboes made of synthetic materials. A soprano oboe measures roughly 65 cm (25 1⁄2 in) long, with metal keys, a conical bore and a flared bell. Sound is produced by blowing into the reed and vibrating a column of air. The distinctive oboe tone is versatile, and has been described as "bright".[1] When the term oboe is used alone, it is generally taken to mean the standard treble instrument rather than other instruments of the family, such as the cor anglais (English horn) or the oboe d'amore.