Look at this trumpetI didn't know there were original instruments of this type which were still playable !
I usually post about math/music, but I also like strange musical instruments, so let me tell you the story of the "English slide trumpet"

(1/n)

The trumpet is known since the antiquity, but until the 19th century it had no valves to play notes.

Its design was basically a very long piece of tubing flared at one end and with a mouthpiece at the other one.

So how do you play notes ?

(2/n)

Leaving out complicated details about the mouthpiece and the flare, such an instrument has a fundamental frequency f0, and resonant frequencies at integer multiples 2*f0, 3*f0, 4*f0, etc. of the fundamental frequency.

(3/n)

2*f0 is one octave above the fundamental frequency
3*f0 is one octave and a fifth above it
4*f0 is two octaves above it

If we take 4*f0 as reference, the next ones are in ratios 5/4 (a major third), 3/2 (a fifth), 7/5 (uh oh), 2 (an octave): you can play a bugle call !

(4/n)

If we now take 8*f0 as a reference, the next ones are almost forming a diatonic scale:

9/8 (semitone), 5/4 (major third), 11/8 (?), 3/2 (fifth), 13/8 (?), 7/4 (?), 15/8 (major seventh), 2 (octave)

So you can play diatonic melodies! (but we have strange interval ratios)

(5/n)

This is the physics behind the natural trumpet. In the baroque era, it was known as... the baroque trumpet.

See this wonderful video for an introduction :



(6/n)

All the notes were selected and played by the instrumentist carefully controlling the tension of his lips.
These frequencies had to be brought in playable range, and this is why the baroque trumpet has a tubing length of 2.5-3 m, almost twice the length of today trumpets

(7/n)

But these frequencies were very close, so it was really difficult to precisely control the lips without hitting the wrong note.
Players of the baroque trumpet at that time were virtuosos, and often well-paid.

But by the end of the 18th century, music evolved...

(8/n)

Composers began to compose more and more chromatically, so the diatonic scale of the baroque trumpet was not enough. We needed all twelve notes !

In addition, we have seen that some interval ratios were really weird...

How to adapt the trumpet ?

(9/n)

One solution was borrowed from horn playing : hand stopping.

By putting your hand in the flare, you could alter the notes and play chromatically.

Given the shape of the instrument it was difficult to do, and the sound was not the same for all notes

(10/n)

Another solution was Charles Clagget's "chromatic trumpet" made of two tubes with two flares and different lengths, and some sort of rudimentary valve to switch between them

No instrument survive however. There is a drawing in the article below

(11/n)

https://www.hkb-interpretation.ch/fileadmin/user_upload/documents/Publikationen/Bd.6/HKB6_103-153_Maury.pdf

Yet another solution: keyed trumpets. If you can put holes on a clarinet, why not a trumpet ? See below for an original instrument.

Unfortunately, keys don't work well with brass instruments, and you lose the characteristic sound of the baroque trumpet

(12/n)

(Speaking about keyed brass, I could also tell you about the keyed bugle, the serpent, and the ophicleide , but that will be for another time)

(13/n)

Another solution: William Shaw's "harmonic trumpet". See the link below : you will notice four holes, three covered by metal sleeves, the fourth by a key.

It's not keys though, but rather vent holes, which control nodal points of the air column

(14/n) https://www.rct.uk/collection/72313/trumpet

The solution which became the "English slide trumpet" came from John Hyde, who had some instruments built by Richard Woodham.

You take a baroque trumpet, and add a slide which changes the fundamental frequency...

(15/n)

... that way you can have different harmonic series which complete each other to form a chromatic scale !

Click on the link to see a beautiful example of natural trumpet which was later converted to a slide trumpet

(16/n)

http://collections.nmmusd.org/UtleyPages/SlideTrumpets/13505RodenbostelWoodhamTrumpet/RodenbostelWoodhamTrumpet.html

The slide is attached to a clock-spring mechanism which returns it to its base position. You can clearly see it in the first video of this thread...

The English slide trumpet became very popular... in England. They existed until the beginning of the XXth century.

(17/n)

Elsewhere, they were gradually superseded by valved trumpets. The valve mechanism had appeared at the beginning of the XIXth century and saw many developments. There is so much to say about that too !

(18/n)