Valve (wind instrument)
Valves are used in brass instruments to change the tube length in order to enable a chromatic game. When the valve is actuated, the air is passed through an additional pipe loop of a certain length, thus lengthening the air column of the instrument (usually).
The shortening valve is very rarely found as the reverse of the function described. Here the air flows through the valve loop when the valve is not actuated, so that the air column is shortened when it is actuated. Examples of this are the French design of the French horn and the B / C trombone .
Configurations
Brass instruments are typically equipped with three valves (the percentage is approximately the pipe extension in relation to the basic length of the instrument):
- The first valve lowers the natural tone by two semitones (12.4%),
- The second valve lowers the natural tone by a semitone (6.0%),
- The third valve lowers the natural tone by three semitones (19.1%),
If there is another valve, it is usually a quart valve that causes the tone to be lowered by five semitones (33.8%). The corresponding sample calculation can be found below .
Another valve that lowers the tone by a quarter tone (3.0%) is very rare . Some tubes have a fifth valve that extends the overall length by a lower whole tone and rarely also a sixth (larger semitone). These two are used for the compensation described below to ensure the range of the pedal position.
One effect of the fourth valve is the expansion of the pitch range by a fourth down, so that when using 1 + 2 + 3 + 4, neglecting intonation problems, a major seventh down is possible (e.g. b → B). In the lowest area of the scale, the "tritone" gap can thus be closed directly above the pedal tone.
The second effect of the fourth valve is to solve intonation problems in connection with the valve combinations 1 + 3 and 1 + 2 + 3. All other valves are used for further compensation.
The “stuffing valve” on the French horn extends by approx. 10% and thus compensates for the increase in tone caused by the complete “stopping” of the horn bell by hand. The actual “stuffing” effect is not created by operating the valve!
Construction methods and history
Nowadays there are two main types of construction:
- the pump valve (also called Périnet valve ) and
- the rotary valve (also known as a cylinder valve ).
The valve tube loops (see below) usually have a cylindrical bore (inner diameter) and - if they are long enough - their own valve tuning slide for fine tuning .
For the history of the valve, see also valve horn .
Pump valve (Périnet valve)
The modern pump valve goes back to a valve design first presented by François Périnet in 1838, which is why it is also called the Périnet valve . Valves of this type have a cylindrical valve body (shown as a light brown rectangle in the figure on the right ), which is operated against spring pressure by means of a finger cap ( light brown "T-piece" ) . Two air channels in the valve body ( light red, inside ) redirect the air flow through the valve loop ( red ) when the cap is operated.
A pump valve is characterized by the fact that not only is its valve body cylindrical, but also almost the entire pipe cross-section in its course. Due to the design, the air inlets of both the main pipe and the pipe loop are generally at a different height than their air outlets. The spring lies in the cavity either above or below the valve body ( dark brown ).
With this design, the distance covered by the valve body is basically at least the diameter of the main pipe. In the case of the tuba , in which the diameter of the bores is up to> 20 millimeters, this can pose technical problems; Périnet valves are particularly easy to maintain because the valve bodies can be removed from their housing simply, quickly and usually without tools.
The pump valve design is the most widespread today and is found, for example, in the vast majority of trumpets .
precursor
The valve, invented by Heinrich Stölzel in 1813, followed the principle of the later Périnet valve, but in contrast to the current design, the air still flowed in from the bottom. The valve was a new type of component in Stölzel's time . Until now all horns were natural horns , but with a valve it was now possible to divert the air blown into a metal horn instrument into intermediate tubes, lengthen the air column and thus achieve a deeper tone. Based on Stölzel's new valve horn , which was initially only equipped with two valves, there was a further development to three valves, which were also installed in other brass instruments and brought the whole family of instruments to completely new uses in orchestras. By 1860, the chromatic horn had established itself in all orchestras.
Berlin valve
Another early form of the pump valve, in addition to that of Stölzel from 1813, was the so-called Berlin valve (or Berlin pump ), which was developed by Stölzel in 1827 and, independently of this, by Wilhelm Wieprecht in 1833 . The Berlin valve had side inlets for the valve loop that were level with the inlets for the main pipe.
Rotary valve
The rotary valve has a valve body with two channels which, however, rotates 90 ° around its vertical axis when the valve is actuated . Valve loop and main pipe open into the housing at the same height.
A spring-loaded lever, which is connected to the valve body either via mechanical joints or via a cord mechanism, is usually used for actuation. Another design is that of the lockable control valve , with which the entire instrument or a specific valve can be switched to a different basic setting.
The rotary valve was developed in 1818 when Friedrich Blühmel and Heinrich Stölzel were asked to include this design in the patent they applied for. Further developments, namely by Joseph Riedl in Vienna in 1835 and Leopold Uhlmann in 1843, finally led to the form that is still in use today.
The valve body with its bearing pins is traditionally made slightly conical for manufacturing reasons ( cone ratio approx. 1:40), and through the use of more precise processing machines, it has also been cylindrical with ball bearings for some years . The material used is
- for the valve body: traditionally brass , bronze is more durable , plastic with stainless steel bearing pins .
- for the valve housing (traditional "bush"): brass or nickel silver
Rotary valves are particularly common on the French horn and on the German types of common wind instruments such as the German concert trumpet and as a quart valve on the German concert trombone . They can also be found on wind instruments of continental European folk music such as the tenor horn and baritone horn . As a result of the leverage, the valve travel can be reduced at the expense of higher actuation forces, which is why rotary valves are also widely used in tubes.
Playing technique differences
When a valve is depressed, the air flow is briefly directed through the valve extension and the valve connection. This creates a pipe length that is not exactly defined, so the pitch of the note to be played is extremely variable. The sound does not sound clean, but nasal, suppressed, dull and muffled. It sometimes happens to beginners that they accidentally switch the valve only halfway or too slowly, or that the valve hangs due to insufficient oiling, and exactly then an undesirable "squeeze" effect occurs.
Mostly in trumpets with pump valves, this effect is sometimes used deliberately, which can be awkward in traditional classical music, in jazz, salsa, pop music or in the so-called new classical music (after 1950): the squeezer by the half-pressed valve and associated phrasing by means of valves that are switched too slowly (e.g. with the jazz trumpeter Chet Baker ). This way of playing a glissando effect is also possible with valve instruments . This way of playing is more difficult on trumpets with rotary valves: Due to their construction, the rotary valves are located at an acoustic point where there is predominantly an oscillation belly (pressure maximum) of the oscillating air column, which makes it difficult for the wind player to influence the lips and oral cavity. In conventional perinet trumpets, the valves are structurally positioned in the acoustic half of the pipe length, where vibration nodes (pressure minima) are relatively often. There is also a difference in the pressure path of the valve: for trumpets with pump valves it is about 17 mm, for rotary valves it is about 8 mm. The position control of the valve position is better with a longer pressure path.
These construction differences arose accidentally or inevitably in the design of the instruments and cannot be related to the actual mechanical valve construction in terms of instrument construction. A special use or preference of one or the other valve construction is to be seen predominantly in the historical context with the concrete history of music and its musical styles .
Another interpretive playing technique, which is often audible with pump valves, is the " tremolo ". There are numerous special fingerings (called false fingerings in English pedagogical reading ), which for reasons of intonation are either not used in principle or only used as so-called auxiliary fingerings in exceptional cases for real trills. The special grips include, for example, the g (0 or 1 + 3), b (1 or 1 + 2 + 3), c (0 or 2 + 3), c sharp (1 + 2, 3 or 1 + 2 + 3), d (1 or 1 + 3), es (2 or 2 + 3) etc. The alternative or special fingerings, due to the ever narrower overtones, become more and more numerous the higher the notes are selected. The tremolo is created by alternately replacing a standard grip with an alternative or special grip as quickly as possible, creating a timbre trill at the same pitch. This way of playing has also long been established in jazz and its related styles and is sometimes expressly required by contemporary classical composers.
Due to the musical stylistic traditions, the mechanically simpler mass production and also the "squeeze" and "tremolo" technique, the perinet trumpet with pump valves has prevailed over the trumpet with rotary valves in jazz worldwide.
Conical valve machine
In high-quality instruments with a wide length (e.g. baritone horn or tuba ), the quart valve and any other valves with very long pipe loops sometimes have a larger bore than the other valves. The reason for this construction is that the timbre of such instruments is determined by their strongly conically widening bore. When using the valves, however, a more or less long section with a cylindrical bore is interposed. The longer this cylindrical passage, the more the timbre and response changes compared to the “open” instrument (i.e. no valve is used), which is usually undesirable.
Special forms
Further rotary valves:
- Thayer valve . Due to its construction, it is only used for the trumpet's fourth valve .
Other pump valves:
- Double slide valve on the Wiener Horn : Two simultaneously moving valve tubes switch between straight and 90 ° angled air passage. The construction requires a relatively large minimum length of the pipe extension of the valve.
Intonation problems
If two or more valves are used in combination, the intonation of the sounding tone does not correspond to the arithmetical sum of their intervals, but to a tone that is too high. This is due to the fact that the additional pipe length connected through each valve in the resonance body is only calculated to lower the air column of the open instrument by a certain interval, but does not take into account the air column that has already been lengthened by another valve. For the same reason, the slide positions on the trombone when the fourth valve is operated no longer correspond to those on the open instrument, but are progressively further back - the entire slide length is now only sufficient for a total of six positions, the last of which with the seventh position collapses with an open instrument.
Sample calculation
To lower the tone by a semitone, the pipe must be lengthened by about six percent. In the case of an instrument with an open tube length of 100 cm, the pull of the second valve has a tube length of six centimeters.
To lower the tone by two semitones, another six percent must be added. This time, however, it is six percent of the new base value 106 cm, i.e. 6.36 cm, so that a total of 112.36 cm is required. Therefore, the pipe length of the first valve train in this example is 12.36 cm.
To lower the tone by another semitone, six percent are added - from the basic 112.36 cm, i.e. 6.74 cm. The total length required is therefore 119.1 cm, the third valve slide must be 19.1 cm long.
In order to lower the tone by four semitones, a further six percent pipe length is required - but from the new basic value 119.1 cm. The correct value would be 7.15 cm. The first valve is significantly longer, but the second a little shorter than the required value. The valve combination (2 + 3) is used in practice and comes very close to the required pipe length, but is actually a little too high.
The same applies to all other valve combinations. The intonation when using several valves at the same time is therefore basically more or less unclean if there is no compensation in any form. The quintessence of this insight: the fewer valves are required, the better the tone.
possible solutions
In principle, as few valves as possible should be used.
In the case of the small differences in the “short” valve combination (1 + 2), compensation is usually done by ear via the attachment. The use of the clean handle 3 would be desirable, but in practice it is mostly not possible, since the combination 1 + 2 is in the foreground in the fingering tables of the instrumental schools and thus in the training.
In the case of instruments with a rather short overall length, such as the trumpet, the difference in combination with the third or first valve is usually compensated for by simply pulling out the valve slide of the third valve.
With classic tuba designs such as the imperial bass, the main tuning slide is specially designed to be pulled out by the player with the left hand during play to compensate.
In the case of tubes and other instruments with a large tube length, however, the difference can be twelve centimeters and more. For this reason, the manufacturers provide other options in terms of design for high-quality models:
Fourth valve (quart valve)
In the trumpet, the notes that are affected by the problem are in the lower register, which is rarely required, a little above the second natural tone.
For instruments that are often played in this position, a fourth valve is often found as the most cost-effective measure, which extends the tube length by the amount required for a fourth (for example on piccolo trumpets , baritone horns , euphoniums and simple tubas, rarely also flugelhorns.)
It thus replaces the valve combination (1 + 3), so that the frequently requested pure fourth can be intonated cleanly under the third natural note. The seldom required excessive fourth underneath is intoned with the combination (2 + 4) in any case far better than on (1 + 2 + 3). Like the diminished fourth to (2 + 3), which is also less frequently required, it can be compensated by tuning slide in an emergency.
Compensated valves, compensation system
The English instrument maker D. J. Blaikely patented an automatic compensation system in 1878. The first two valves of a three-valve instrument have additional pipe loops on the back; their valve bodies have three instead of two channels.
In this system, if the compensated third valve is operated in combination with the other valves, the air is passed through their normal valve loop and additionally through the compensation loops, so that the total pipe length corresponds to the required amount.
Similarly, four-valve instruments have compensation loops on the first three valves that are only activated in combination with the fourth valve.
As a result, instruments compensated in this way have at least approximately the correct tube length on all combinations with the compensated valve. Four-valve compensated instruments even have the decisive advantage of correct intonation over the entire octave between the fundamental and the second natural . This form of compensation is therefore particularly important for low instruments such as the tuba and the euphonium .
For structural reasons, this solution is particularly suitable for instruments with pump valves .
A disadvantage of compensated valves can be that the instruments on them sound duller and respond more poorly. The reasons for this are presumably poorly laid pipe loops in the compensation system as well as turbulence that occurs at narrow points, for example in the valves.
While all instruments were affected by this in the early days of their development, this only applies today to compensated French horns , the only common rotary valve instruments that are also manufactured with compensation.
Additional conventional valves
In order to avoid the widespread sound and response problems of earlier compensation systems, some manufacturers have switched to installing additional valves instead, the pipe lengths of which are designed exclusively for use in combination with other valves.
This approach has been preserved with the tubes to this day : Many high-quality double bass tubes have a fifth valve, which is calculated to be used instead of the first valve in combination with the fourth valve ("extended big second"). Bass voices in F have up to six valves.
Additional valve loops
Another alternative is to add two pipe loops to each valve. An additional valve can be used to switch between them, which at the same time changes the basic mood by a certain interval. In this way you get two instruments with different basic tuning (“side”) in one. For notes with problematic intonation on the one hand, this sometimes results in less problematic alternative fingerings on the other.
Today, this approach is essentially important for French horns, which since the design first presented by Eduard Kruspe and Bartholomäus Geisig in Erfurt in the 19th century, usually as F / Bb or Bb / f double horn, more rarely as F / Bb / f- Triple horn are executed.
Comparable, fully developed double tubes, on the other hand, are extremely rare these days.
Intonation slide (trigger)
Under a trigger (English for deduction ) is understood to mean a compensation by a device that makes it easy to vary the length of a valve train or the main tuning train. This device, also known as intonation pushers or equalizers, consists either of a ring or U-shaped "saddle" connected to the tuning slide that is moved with a finger, or of a mechanical lever that is pressed with a finger and usually a return spring owns.
As an additional intonation aid , triggers are often included as standard on trumpets , cornets , flugelhorns as well as on high-quality tubas and euphoniums . On inexpensive trumpets, the trigger or retuning mechanism for the first valve sometimes falls victim to cost-saving measures. Instead, these instruments have a longer pipe loop on the third valve because the manufacturer assumes that intonation correction is only required when using the third valve.
literature
- Herbert Heyde: The valve wind instrument - its development in the German-speaking area from the beginning to the present. Breitkopf & Härtel, Wiesbaden 1987, ISBN 3-7651-0225-3 .