trumpet techniques. Flutter tonguing: The trumpeter rolls the tip of the tongue (as if rolling an "R" in Spanish) to produce a 'growling like' tone. This technique is widely employed by composers like Berio and Stockhausen. Growling: Simultaneously playing tone and using the back of the tongue to vibrate the uvula, creating a distinct sound. Most trumpet players will use a plunger with this technique to achieve a particular sound heard in a lot of Chicago Jazz of the 1950s. Double tonguing: The player articulates using the syllables ta-ka ta-ka ta-ka. Triple tonguing: The same as double tonguing, but with the syllables ta-ta-ka ta-ta-ka ta-ta-ka. Doodle tongue: The trumpeter tongues as if saying the word doodle. This is a very faint tonguing similar in sound to a valve tremolo. Glissando: Trumpeters can slide between notes by depressing the valves halfway and changing the lip tension. Modern repertoire makes extensive use of this technique. Vibrato: It is often regulated in contemporary repertoire through specific notation. Composers can call for everything from fast, slow or no vibrato to actual rhythmic patterns played with vibrato. Pedal tone: Composers have written notes as low as two-and-a-half octaves below the low F at the bottom of the standard range. Extreme low pedals are produced by slipping the lower lip out of the mouthpiece. Claude Gordon assigned pedals as part of his trumpet practice routines, that were a systematic expansion on his lessons with Herbert L. Clarke. The technique was pioneered by Bohumir Kryl. Microtones: Composers such as Scelsi and Stockhausen have made wide use of the trumpet's ability to play microtonally. Some instruments feature a fourth valve that provides a quarter-tone step between each note. The jazz musician Ibrahim Maalouf uses such a trumpet, invented by his father to make it possible to play Arab maqams. Valve tremolo: Many notes on the trumpet can be played in several different valve combinations. By alternating between valve combinations on the same note, a tremolo effect can be created. Berio makes extended use of this technique in his Sequenza X. Noises: By hissing, clicking, or breathing through the instrument, the trumpet can be made to resonate in ways that do not sound at all like a trumpet. Noises may require amplification. Preparation: Composers have called for trumpeters to play under water, or with certain slides removed. It is increasingly common for composers to specify all sorts of preparations