Difference between a whistle and a flute

Whistles and flutes both produce sound by the action of a free airjet against a sharp edge coupled with a resonating tube. However, the generally accepted difference between a whistle and a flute is that a whistle uses an airjet whose shape is determined by a nozzle of fixed shape, whereas with a flute, the shape of the airjet is controlled by the shape of the players lips (embouchure). Whistles are generally easier to play (at least in the beginning) than flutes, however a much greater range of expression may be obtained with a flute.

End-blown versus transverse flutes

The traditional Western orchestral flute is a transverse flute in that it is played to one side and air is blown across a hole near one end of the instrument. The same arrangement is used for the orchestral piccolo and the fife used in marching bands. An end-blown flute is held directly in front of the player (like a clarinet or oboe) and is played by blowing air into a hole at the end of the instrument.

The main advantage of the transverse design would appear to be that correct intonation can be maintained with a relatively large tube bore to length ratio, maximising the sound volume obtained from the instrument. A potential disadvantage of the transverse design is the rather unnatural playing attitude required.

End blown flutes generally can not be played as loud as transverse flutes of the same size. However, the end-blown arrangement allows a wide range of tone colours to be produced from breathy to cool and clear. Furthermore, the tone of end blown flutes is appropriate for use in traditional folk music.The modern transverse flute can be overpowering in such contexts.

Keys or Keyless?

The tone holes on an orchestral flute are covered by pads operated by various keys. The use of tone hole pads enables the use of larger tone holes than is possible when the tone holes have to be covered using fingers. This enables a larger bore tube to be used, leading to a bigger sound. The use of keys enables the tone holes to be placed in the acoustically correct location independent of the physical constraints imposed by the reach of a human hand. Furthermore, by using additional tone holes operated by different keys, a fully chromatic instrument can be developed.

Traditional flutes are generally keyless, that is, the tone holes are covered by fingers. Most have six tone holes. the tone hole nearest the blowing hole is sometimes underneath the instrument such that it is operated by the thumb. There does not appear to a good acoustical reason for doing this.

Flute Tuning

It is intriguing that most flutes, apart from those from the Middle East, are tuned to the seven note diatonic scale (the white notes on the piano). With six tone holes and a limited amount of forked fingering (open holes between closed holes),  diatonic scales may be played in two keys. Using half fingering (covering up only part of the tone hole) a fully chromatic scale can be played, but this is generally difficult and not musically useful.

Western preference is for a diatonic scale with equal temperament, that is, each octave divided into 12 equal semitones. However, natural tuning based on whole number frequency ratios between tones is typically used outside of Western influence. The difference between a natural and equal tempered scale is most noticeable in the third note which in natural tuning sounds flat to western ears. Other differences are small and effectively of the same order as the accuracy with which the instruments are made.

Traditional End blown flutes

End blown flutes are arguably the oldest of all tuned musical instruments. Ancient Chinese designs have been found that date back to around 5000BC. The earliest remaining end blown flutes are those made from a hollow bone with notch cut in one end. However it is likely that man has been making flutes from hollow reeds or plant stems for as long as he has been making tools.

Today, the end blown flute is still played extensively in South America, the Middle East, China and Japan. The South American end blown flute is known as a kena and is typically made from bamboo or other hollow-stemmed plant. It is most widely played in Peru and Bolivia and is associated with the people of the Andes mountain range. It is relatively easy to play and has a fairly strong, breathy tone, but has a rather limited useful acoustic range due to the large bore to length ratio. From experience, most of the instruments for sale in South America have rather poor intonation, with most having very out of tune octaves. This is partly due to natural irregularities in the instrument bore and partly due the large bore to length ratio.

The main end blown flute in China is called a Xiaou (pronounced show as in cow). This instrument is made from bamboo and has a relatively small bore to length ratio and a small blowing hole. It produces a delicate but rich tone with a lowest note of D above middle C and a useful range of over two octaves. The instrument is almost 1m in length, although the tone holes only extend to half this length. The remaining part of the instrument acts as an additional resonator, though with questionable positive effect. Indeed, sawing 40cm off the end of a Xiaou seems to make no difference to the sound at all. Some of the oldest surviving written music is for the Xiaou with manuscripts dating back to around 9AD (well before Western music was written down).

In Japan, the most important end blown flute is the Shakuhatchi, which is a historical derivative of the Xiaou (so claim the Chinese). The Shakuhatchi is made from the root end of a bamboo plant. It has a convergent-divergent bore profile formed by coating the inside of the bore with lacquer. The blowing hole is relatively large with a straight-edged striking face made from buffalo horn. The instrument is difficult to master, but when played well is a highly expressive instrument.

End blown flutes