Editing Brass instrument (section)

=={{anchor|Valves}} Valves==
<!--Valve (music) redirects here-->
{{Main|Brass instrument valves}}
[[File:Brass-instrument-keys-2759.jpg|thumb|right|Brass instrument piston valves]]
[[Image:Dugattyus szelep.png|thumb|right|Piston valve]]
[[Image:Forgoszelep.png|thumb|right|Rotary valve]]
[[Image:Brass instrument slides.svg|thumb|right|Slide]]
Valves are used to change the length of tubing of a brass instrument allowing the player to reach the notes of various harmonic series. Each valve pressed diverts the air stream through additional tubing, individually or in conjunction with other valves. This lengthens the vibrating air column thus lowering the fundamental tone and associated harmonic series produced by the instrument. Designs exist, although rare, in which this behaviour is reversed, i.e., pressing a valve removes a length of tubing rather than adding one. One modern example of such an ascending valve is the Yamaha YSL-350C trombone,<ref name="YSL-350C"/> in which the extra valve tubing is normally engaged to pitch the instrument in B{{music|flat}}, and pressing the thumb lever removes a whole step to pitch the instrument in C. Valves require regular [[lubrication]].

A core standard valve layout based on the action of three valves had become almost universal by (at latest) 1864 as witnessed by [[Arban method|Arban's method]] published in that year. The effect of a particular combination of valves may be seen in the table below. This table is correct for the core three-valve layout on almost any modern valved brass instrument. The most common four-valve layout is a superset of the well-established three-valve layout and is noted in the table, despite the exposition of four-valve and also five-valve systems (the latter used on the tuba) being incomplete in this article.

{| class="wikitable"
|+ Valve combination and effect on pitch
!Valve combination !!Effect on pitch !!Interval !!Tuning problems
|-
|2 ||{{1/2}} step ||[[Minor second]] ||
|-
|1 ||1 step ||[[Major second]] ||
|-
|1+2 or 3 ||{{frac|1|1|2}} step ||[[Minor third]] ||Very slightly sharp
|-
|2+3 ||2 steps ||[[Major third]] ||Slightly sharp
|-
|1+3 or 4 ||{{frac|2|1|2}} steps ||[[Perfect fourth]] ||Sharp (1+3 only)
|-
|1+2+3 or 2+4 ||3 steps ||[[Tritone]] ||Very sharp (1+2+3 only)
|-
|1+4 ||{{frac|3|1|2}} steps ||[[Perfect fifth]] ||
|-
|1+2+4 or 3+4 ||4 steps ||[[Augmented fifth]] ||Flat
|-
|2+3+4 ||{{frac|4|1|2}} steps ||[[Major sixth]] ||Slightly sharp
|-
|1+3+4 ||5 steps ||[[Minor seventh]] ||Sharp
|-
|1+2+3+4 ||{{frac|5|1|2}} steps ||[[Major seventh]] ||Very sharp
|}

===Tuning===
Since valves ''lower'' the pitch, a valve that makes a pitch too low (flat) creates an interval wider than desired, while a valve that plays sharp creates an interval narrower than desired. [[Intonation (music)|Intonation]] deficiencies of brass instruments that are independent of the tuning or temperament system are inherent in the physics of the most popular valve design, which uses a small number of valves in combination to avoid redundant and heavy lengths of tubing<ref>[https://web.archive.org/web/20090727085204/http://music.ou.edu/applied/horn/intonation.html Understanding Brass Instrument Intonation], University of Oklahoma Horn Studio</ref> (this is entirely separate from the slight deficiencies between [[Classical music|Western music's]] dominant [[Equal temperament|equal (even) temperament system]] and the [[Just intonation|just (not equal) temperament]] of the harmonic series itself). Since each lengthening of the tubing has an inversely proportional effect on pitch ([[Pitch of brass instruments]]), while pitch perception is logarithmic, there is no way for a simple, uncompensated addition of length to be correct in every combination when compared with the pitches of the open tubing and the other valves.<ref>{{Cite web|url=http://www.phys.unsw.edu.au/jw/brassacoustics.html#valves|title=Brass instrument (lip reed) acoustics: an introduction|website=www.phys.unsw.edu.au|access-date=2017-12-10|archive-url=https://web.archive.org/web/20140814070408/http://www.phys.unsw.edu.au/jw/brassacoustics.html#valves|archive-date=2014-08-14|url-status=dead}}</ref>

====Absolute tube length====
For example, given a length of tubing equaling 100 units of length when open, one may obtain the following tuning discrepancies:

{| class="wikitable"
|+ Valve combination and creation of pitch discrepancies
!Valve(s) !!Desired pitch !!Necessary valve length !!Component tubing length !!Difference !!Slide positions
|-
|Open tubing ||A{{music|#}}/B{{music|b}} ||0 || – || – ||1
|-
|2 ||A ||5.9 || – || – ||2
|-
|1 ||G{{music|#}}/A{{music|b}} ||12.2 || – || – ||3
|-
|1+2 or 3 ||G ||18.9 ||18.1 ||0.8 ||4
|-
|2+3 ||F{{music|#}}/G{{music|b}} ||25.9 ||24.8 ||1.1 ||5
|-
|1+3 or 4 ||F ||33.5 ||31.1 ||2.4 ||6 or T
|-
|1+2+3 or 2+4 ||E ||41.4 ||37 ||4.4 ||7 or T+2
|-
|1+4 ||D{{music|#}}/E{{music|b}} || – ||45.7 || – ||T+3
|-
|1+2+4 or 3+4 ||D || – ||52.4 || – ||T+4
|-
|2+3+4 ||C{{music|#}}/D{{music|b}} || – ||58.3 || – ||T+5
|-
|1+3+4 ||C || – ||64.6 || – ||T+6
|-
|1+2+3+4 ||B || – ||70.5 || – ||T+7
|}

Playing notes using valves (notably 1st + 3rd and 1st + 2nd + 3rd) requires [[#Tuning compensation|compensation]] to adjust the tuning appropriately, either by the player's lip-and-breath control, via mechanical assistance of some sort, or, in the case of horns, by the position of the stopping hand in the bell. 'T' stands for trigger on a trombone.

====Relative tube length====

Traditionally<ref>Christopher W. Monk, "The Older Brass Instruments: Cornet, Trombone, Trumpet", in ''Musical Instruments Through the Ages'', revised edition, edited by Anthony Baines, {{Page needed|date=October 2015}}<!--Inclusive pages needed.--> (London: Faber and Faber, 1966): {{Page needed|date=October 2015}}<!--Specific page reference for the word "traditionally" needed.--></ref> the valves lower the pitch of the instrument by adding extra lengths of tubing based on a [[just tuning]]:
* 1st valve: {{frac|1|8}} of main tube, making an interval of 9:8, a [[pythagorean major second]] 
* 2nd valve: {{frac|1|15}} of main tube, making an interval of 16:15, a [[just minor second]] 
* 3rd valve: {{frac|1|5}} of main tube, making an interval of 6:5, a [[just minor third]]

Combining the valves and the harmonics of the instrument leads to the following ratios and comparisons to 12-tone equal tuning and to a common [[five-limit tuning]] in C:
{| class="wikitable" style="text-align: center"
|- valign="top"
! Valves || Har-<br />monic || Note || Ratio || Cents || Cents from<br />12ET || Just<br />tuning || Cents from<br />just
|-
|○○○||2||C||1:1||0||0||1:1||0
|-
|●●●||3||C{{music|#}}/D{{music|b}}||180:167||130||30||16:15||18
|-
|●○●||3||D||60:53||215||15||9:8||11
|-
|○●●||3||D{{music|#}}/E{{music|b}}||45:38||293||−7||6:5||−23
|-
|●●○||3||E||180:143||398||−2||5:4||12
|-
|●○○||3||F||4:3||498||−2||4:3||0
|-
|○●○||3||F{{music|#}}/G{{music|b}}||45:32||590||−10||45:32||0
|-
|○○○||3||G||3:2||702||2||3:2||0
|-
|○●●||4||G{{music|#}}/A{{music|b}}||30:19||791||−9||8:5||−23
|-
|●●○||4||A||240:143||896||−4||5:3||12
|-
|●○○||4||A{{music|#}}/B{{music|b}}||16:9||996||−4||9:5||−22
|-
|○●○||4||B||15:8||1088||−12||15:8||0
|-
|○○○||4||C||2:1||1200||0||2:1||0
|-
|●●○||5||C{{music|#}}/D{{music|b}}||300:143||1283||−17||32:15||−29
|-
|●○○||5||D||20:9||1382||−18||9:4||−22
|-
|○●○||5||D{{music|#}}/E{{music|b}}||75:32||1475||−25||12:5||−41
|-
|○○○||5||E||5:2||1586||−14||5:2||0
|}

=== Tuning compensation ===
The additional tubing for each valve usually features a short tuning slide of its own for fine adjustment of the valve's tuning, except when it is too short to make this practicable. For the first and third valves this is often designed to be adjusted as the instrument is played, to account for the deficiencies in the valve system.
[[Image:Trumpet valve bypass.svg|thumb|Trumpet valve bypass (depressed)]]

In most trumpets and cornets, the compensation must be provided by extending the third valve slide with the third or fourth finger, and the first valve slide with the left hand thumb (see [[#Trigger or throw|Trigger or throw]] below). This is used to lower the pitch of the 1–3 and 1–2–3 valve combinations. On the trumpet and cornet, these valve combinations correspond to low D, low C{{music|sharp}}, low G, and low F{{music|sharp}}, so chromatically, to stay in tune, one must use this method.

In instruments with a fourth valve, such as tubas, euphoniums, [[piccolo trumpet]]s, etc. that valve lowers the pitch by a perfect fourth; this is used to compensate for the sharpness of the valve combinations 1–3 and 1–2–3 (4 replaces 1–3, 2–4 replaces 1–2–3). All three normal valves may be used in addition to the fourth to increase the instrument's range downwards by a perfect fourth, although with increasingly severe [[Intonation (music)|intonation]] problems.

When four-valved models without any kind of compensation play in the corresponding register, the sharpness becomes so severe that players must finger the note a half-step below the one they are trying to play. This eliminates the note a half-step above their open fundamental.

Manufacturers of low brass instruments may choose one or a combination of four basic approaches to compensate for the tuning difficulties, whose respective merits are subject to debate:

==== Compensation system ====
In the Compensation system, each of the first two (or three) valves has an additional set of tubing extending from the back of the valve. When the third (or fourth) valve is depressed in combination with another one, the air is routed through both the usual set of tubing plus the extra one, so that the pitch is lowered by an appropriate amount. This allows compensating instruments to play with accurate intonation in the octave below their open second partial, which is critical for tubas and euphoniums in much of their repertoire.

The compensating system was applied to horns to serve a different purpose. It was used to allow a double horn in F and B{{music|flat}} to ease playing difficulties in the high register. In contrast to the system in use in tubas and euphoniums, the default 'side' of the horn is the longer F horn, with secondary lengths of tubing coming into play when the first, second or third valves are pressed; pressing the thumb valve takes these secondary valve slides and the extra length of main tubing out of play to produce a shorter B{{music|flat}} horn. A later "full double" design has completely separate valve section tubing for the two sides, and is considered superior, although rather heavier in weight.

==== Additional valves ====
Initially, compensated instruments tended to sound stuffy and blow less freely due to the air being doubled back through the main valves. In early designs, this led to sharp bends in the tubing and other obstructions of the air-flow. Some manufacturers therefore preferred adding more 'straight' valves instead, which for example could be pitched a little lower than the 2nd and 1st valves and were intended to be used instead of these in the respective valve combinations. While no longer featured in euphoniums for decades, many professional tubas are still built like this, with five valves being common on CC- and BB{{music|flat}}-tubas and five or six valves on F-tubas.{{citation needed|date=July 2012}}

Compensating double horns can also suffer from the stuffiness resulting from the air being passed through the valve section twice, but as this really only affects the longer F side, a compensating double can be very useful for a 1st or 3rd horn player, who uses the F side less.

==== Additional sets of slides on each valve ====
Another approach was the addition of two sets of slides for different parts of the range. Some euphoniums and tubas were built like this, but today, this approach has become highly exotic for all instruments except horns, where it is the norm, usually in a double, sometimes even triple configuration.

==== Trigger or throw ====
<!--[[Throw (music)]], [[Throw (instrument)]], [[Throw (brass instrument)]], [[Throw (musical instrument)]], [[Trigger (music)]], [[Trigger (instrument)]], [[Trigger (brass instrument)]], and [[Trigger (musical instrument)]] redirect directly here.-->
[[File:Yamaha Flugelhorn YFH-8310Z.jpg|thumb|Flugelhorn with three pistons and a trigger]]

Some valved brass instruments provide '''triggers''' or '''throws''' that manually lengthen (or, less commonly, shorten) the main tuning slide, a valve slide, or the main tubing. These mechanisms alter the pitch of notes that are naturally sharp in a specific register of the instrument, or shift the instrument to another playing range. Triggers and throws permit speedy adjustment while playing.

Trigger is used in two senses:
* A trigger can be a mechanical lever that lengthens a slide when pressed in a contrary direction. Triggers are sprung in such a way that they return the slide to its original position when released.
* The term "trigger" also describes a device engaging a valve to lengthen the main tubing, e.g. lowering the key of [[#Trombone|certain trombones]] from B{{Music|flat}} to F.

A throw is a simple metal grip for the player's finger or thumb, attached to a valve slide. The general term "throw" can describe a u-hook, a saddle (u-shaped grips), or a ring (ring-shape grip) in which a player's finger or thumb rests. A player extends a finger or thumb to lengthen a slide, and retracts the finger to return the slide to its original position.

====Examples of instruments that use triggers or throws====

=====Trumpet or cornet=====
Triggers or throws are sometimes found on the first valve slide. They are operated by the player's thumb and are used to adjust a large range of notes using the first valve, most notably the player's written top line F, the A above directly above that, and the B{{music|flat}} above that. Other notes that require the first valve slide, but are not as problematic without it include the first line E, the F above that, the A above that, and the third line B{{music|flat}}.

Triggers or throws are often found on the third valve slide. They are operated by the player's fourth finger, and are used to adjust the lower D and C{{music|#}}. Trumpets typically use throws, whilst cornets may have a throw or trigger.

=====Trombone=====
{{Main|F attachment}}

Trombone triggers are primarily but not exclusively<ref name="YSL-350C">[http://www.yamaha.com/yamahavgn/CDA/ContentDetail/ModelSeriesDetail.html?CNTID=2265&CTID=242600 Yamaha Catalog YSL-350C] {{Webarchive|url=https://wayback.archive-it.org/all/20090428193549/https://www.yamaha.com/yamahavgn/CDA/ContentDetail/ModelSeriesDetail.html?CNTID=2265&CTID=242600 |date=2009-04-28 }} with ascending B{{music|flat}}/C rotor</ref> installed on the F-trigger, bass, and contrabass trombones<ref>{{cite web|url=http://www.yamaha.com/yamahavgn/CDA/List/ModelSeriesListHE.html?CTID=242800|title=Yamaha Catalog "Professional Trombones"|website=yamaha.com|access-date=2009-10-25|archive-url=https://web.archive.org/web/20090901162303/http://www.yamaha.com/yamahavgn/CDA/List/ModelSeriesListHE.html?CTID=242800|archive-date=2009-09-01|url-status=dead}}</ref> to alter the length of tubing, thus making certain ranges and pitches more accessible.

=====Euphoniums=====
A euphonium occasionally has a trigger on valves other than 2 (especially 3), although many professional quality euphoniums, and indeed other brass band instruments, have a trigger for the main tuning slide.<ref>The [[Besson (music company)|Besson]] Prestige [https://web.archive.org/web/20110102123040/http://www.besson.com/en/instruments.php?mode=productDetails&pid=42 euphonium].</ref>

=== Mechanism ===
The two major types of valve mechanisms are ''[[rotary valve]]s'' and ''[[piston valve]]s''. The first piston valve instruments were developed just after the start of the 19th century. The ''Stölzel valve'' (invented by [[Heinrich Stölzel]] in 1814) was an early variety. In the mid 19th century the ''Vienna valve'' was an improved design. However many professional musicians preferred rotary valves for quicker, more reliable action, until better designs of piston valves were mass manufactured towards the end of the 19th century. Since the early decades of the 20th century, piston valves have been the most common on brass instruments except for the orchestral horn and the tuba.<ref>[http://www.public.asu.edu/~jqerics/about_articles.htm The Early Valved Horn] by John Q. Ericson, Associate Professor of horn at Arizona State University</ref> See also the article [[Brass Instrument Valves]].