to improve intonation. Some of the partials of the harmonic series that a modern Bb trumpet can play for each combination of valves pressed are in tune with 12-tone equal temperament and some are not. Mute Various types of mutes can be placed in or over the bell, which decreases volume and changes timbre. Of all brass instruments, trumpets have the widest selection of mutes: common mutes include the straight mute, cup mute, harmon mute (wah-wah or wow-wow mute, among other names), plunger, bucket mute, and practice mute. When the type of mute is not specified, players generally use a straight mute, the most common type. Jazz, commercial, and show band musicians often use a wider range of mutes than their classical counterparts, and many mutes were invented for jazz orchestrators. Mutes can be made of many materials, including fiberglass, plastic, cardboard, metal, and "stone lining", a trade name of the Humes & Berg company. They are often held in place with cork. To better keep the mute in place, players sometimes dampen the cork by blowing warm, moist air on it. The straight mute is conical and constructed of either metal (usually aluminum)—which produces a bright, piercing sound—or another material, which produces a darker, stuffier sound. The cup mute is shaped like a straight mute with an additional, bell-facing cup at the end, and produces a darker tone than a straight mute. The harmon mute is made of metal (usually aluminum or copper) and consists of a "stem" inserted into a large chamber. The stem can be extended or removed to produce different timbres, and waving one's hand in front of the mute produces a "wah-wah" sound, hence the mute's colloquial name. Range Using standard technique, the lowest note is the written F below middle C. There is no actual limit to how high brass instruments can play, but fingering charts generally go up to the high C two octaves above middle C. Several trumpeters have achieved fame for their proficiency in the extreme high register, among them Maynard Ferguson, Cat Anderson, Dizzy Gillespie, Doc Severinsen, and more recently Wayne Bergeron, Louis Dowdeswell, Thomas Gansch, James Morrison, Jon Faddis and Arturo Sandoval. It is also possible to produce pedal tones below the low F, which is a device occasionally employed in the contemporary repertoire for the instrument. Extended technique Contemporary music for the trumpet makes wide uses of extended