One of the most ancient and widespread of musical instruments is the flute. Almost every culture on Earth has some sort of flute; some like the end-blown reed flute ney or nai of the Middle East date back to the Ancient World, thousands of years BC. Some, like the instrument most people think of when the word flute is mentioned, the modern metal flute with many keys, can be traced to a specific place and in this case even to one man, Theobald Boehm, who developed it in the late 1840's. As a matter of fact, to distinguish it from other flute systems, the metal flute is called a Boehm System Flute.

A flute produces sound by means of a vibrating column of air set in motion by the player; splitting the air stream of breath does this, and can be accomplished by several methods. The air stream can be split by directing it through a duct and over a ledgelike windway, as in the recorder, flageolette, and tinwhistle. This makes it easy to make a tone, but restricts the dynamic range so shading of loud and soft are not possible on the same pitch. These are the fipple flutes, so named for the old English term for the ducted windway .

Some flutes are merely vessels, closed at the bottom and blown on the top; these sound haunting and rich (like blowing across a Coke bottle as we all did as children) but are limited in range. The pan pipe gets around this by using many tubes, each producing one note. Others have fingerholes to produce more than one tone. Some are also fitted with fipples, as is the ocarina family.

The aforementioned ney or nai is rim-blown, as is the Balkan kaval, using a technique of bilabial blowing, where the end of the tube rests obliquely on the side of both top and bottom lips. This is a difficult technique to master, but produces a special tonal color and great inflectional possibilities. One further refinement is the method of blowing the Persian Classical ney, which uses the toungue to direct the air stream into the tube set between the upper teeth and lip; this is taken from the Turkoman tribes and is called interdental blowing.

Another method is the end-blown flute, such as that used on the Japanese shakuhachi; the end of the tube is rested against the lower lip and the air is directed over a notch, indentation, or wedge-shaped area; the kena of South America is also end blown.

Almost the same sound producing method is used for the transverse flutes of all types; the difference is that the flute body is sideways to the mouth and instead of directing the air over a notch it is split off the far edge of a round or oval hole at one end of the tube, which is closed at the mouth end. In India and China the transverse flute is of great antiquity; Krishna is traditionally pictured playing the transverse flute.

The basic form of these transverse flutes is a mouthhole, called the embouchure, and six open fingerholes. Since these flutes overblow easily and at the octave, the scale is complete with only these holes. Generally they are adjusted by size and spacing to play a major scale, starting from Do (it could be any actual pitch) with all 6 holes closed, and each successive note, Re, MI, etc., is obtained by opening the next hole from the open end of the tube. All six holes open gives Ti, and closing all holes and blowing more intensely give the high Do; and so forth up to the upper limit of the instrument, often a 2 1/2 octave range- sometimes more.

The Indian bansuri is made of thin bamboo in wide variety of lengths, generally North Indians play long, low pitched bansuri and Carnatic musicians of the south prefer shorter bansuri. Occasionally some are made with additional toneholes.

The Chinese Di is also made of bamboo, but thicker walled, and usually the tube is extended in the low end, the extra holes being for tuning and hanging a tassle, not fingering. Their tonal color is augmented by aa additional hole between the 6th fingerhole and the embouchure, which when covered by a thin membrane such as the inside of bamboo gives a buzzing element to the tone.

The Japanese have several transverse flutes, the Shinobue, similar to the Di but without a membrane hole; the Gagaku, Noh, and Kabuki have transverse flutes, and so do the Shinto temples. The Noh fue (flute) is unique do to a construction feature that flattens the overblown notes by up to a tone, matching the Noh singing.

Europe did not know the transverse flute well until after the Crusading period, when it was adopted from the Eastern Empire; it spread widely and quickly, though, and was so popular with the Germanic peoples that it was often known as the "German" flute.

The Renaissance flute was made in several sizes, an Alto in G, a Tenor in D, and a Bass in G or A; it was a straight tube, small finger holes, and produced an expressive tone.

The Baroque period took the tenor flute in D, and made two important changes: the bore was made to taper narrower the further away from the embouchure hole, which helped intonation, and a single Eb key for the right hand little linger was added; this was the typical flute by about1680 or so.

By the Classical period, circa late 1700's to1800, the flute had 6, 8 or more keys, and many had extended lower ranges by lengthening the foot joint and using more keywork for the right hand little finger. Some German makers went even lower by using left hand little finger keys.

The Period between 1810 saw considerable innovation in flutemaking. New woods were available such as grenadilla, pallisander, and rosewood. Glass "crystal" was used in 1806 in France; the later 1800's saw the use of woods including blackwood and ebony, and the first synthetic, ebonite, was used in 1840.

One innovation was made by Charles Nicholson, a well-known flute virtuoso, in 1822, when he introduced the large-tone hole flute, producing a louder tone than the earlier flutes. Other makers adopted his ideas too.

Nicholson's work spurred another musician/inventor towards a new flute system. Theobald Boehm began experimenting in London in1831, and produced his first rationalized flute, with toneholes placed for acoustic reasons, not ergonomic ones, and using ring and closed keys. It was still made of wood with a tapered bore; by 1847, the flute as we use it today was born.

Boehm had completely redesigned the instrument, making a parabolic inner taper to the headjoint to improve intonation; making the body essentially a cylinder, no taper; the fingerholes wer not just placed for acoustic accuracy but were as large as needed for maximizing tone; there was a new type of keywork to manipulate so many keys with only eight fingers and the left hand thumb; it took a while to become universally popular- even in the 20th century some player still had their wooden flutes- but far and away most orchestras and bands are using Boehm flutes.

So much so that the earlier flutes almost became unknown, until the Early Music revival awoke interest in the Renaissance and Baroque flutes. After all, they are the instruments the composers of the time wrote for and understood.

The modern "Irish" flute is an interesting case. First, the flute is not native to Ireland, and the transverse flute was introduced most likely from England. Makers including Dollard of Dublin were in operation by the 1830's, for the classical market.

For traditional Irish flute the historical record is murky at best. Flute is little mentioned in the writings of the 18th and 19th century, although pipes and fiddles are ubiquitous in literary references. Also due to the poverty of the average Irishman of the time, these flutes were beyond the purchasing power of all but the wealthy amateur or professional.

By the end of the 19th century word of mouth suggests the flute was at least known and played in all of Ireland, but the counties of Sligo, Leitrim, Roscommom, Galway, Clare, and Limerick were the hotbed of traditional flute playing. Obviously, too, as Francis O'Neill himself was a flute player, as were several others mentioned in "Irish Minstrels and Musicians" the flute was a well known instrument; today it is as well thought of as the pipes and fiddle if less common, but in the 1800's it may not have had this high status..

Of course the adoption of the metal Boehm system flute caused many of the fine older simple system flutes to wind up in second-hand shops at low prices by the late 1800's and early 1900's- and thus affordable for the poorer Irish. Of course there are a limited number of fine old flutes, so simce the Celtic music revival since the 1950's more makers have begun producing "Irish" flutes. So what makes an "Irish" flute what it is? Wooden tapered bore, large toneholes, little use of the keys (many players don't use the keys they have, and most traditional music can be played easily with NO keys), and a particular playing STYLE using no tongue articulation but rather a wide arsenal of cuts, taps, pops, rolls, cranns, breath accents and pulses for articulation and effect. The tonal ideal is more breathy and reedy, less metalic and pointed than the modern flute ideal sound, and is accomplished by rolling the embouchure towards the lips and blowing in a more focused manner.

One other area of music that still favors the wooden simple system flute is Cuban music, as the preferred type is a wooden Classical flute from the French tradition.

Although outwardly similar to the keyed flutes used in Irish music, the large tone holes so needed for playing Irish dance music in the low and 2nd octave are not needed as Cuban flute players play little in the lowest register and mostly in the 2nd and 3rd register. and use all the tongue articulations of Classical music. Many older wooden flutes not suitable for Irish music- and as such available at a relatively bargain price- are ideal for Cuban music, such as the numerous German small tone-hole flutes. It is essential the keywork be in good repair, as all the keys are used and are needed for many of the 3rd register tones. The low notes below D are not really needed, so many players use 6 key flutes.

Some player now use a hybred flute- a wooden head joint on a Boehm body, but many stick to the old 6 or 8 key flutes. A few also have a flute pitched a minor 3rd higher, called a tercerola; this is used for facilitating playing in certain flat keys.