What is the story behind the shape of the bell on the English horn (AKA the cor anglais)?
But first, a quick look at the clarinet family for a comparison.
The standard clarinet (in Bb or A) has a normal looking "bell-shaped" bell (some kind of rotated exponential curve).
Each of the clarinet's larger siblings such as the basset horn (in F) has a bell that comes off at an upturned angle, and is usually made of metal rather than wood.
I can understand some reasoning behind this – if the bell continued straight downward, then the instrument would be too tall and pointed into the ground. So, the instrument designers have curved it upwards to face the audience. To get the curve smooth it is easier to make it from metal. But importantly, the bell is still basically bell-shaped.
The oboe family is a different.
The standard oboe (in C) has a stumpy little bell with not too much flair to it (no offence intended).
A larger member of the oboe family the English horn (in F) has a "bell" that is very different – it's onion-shaped.
Why don't the oboe and the English horn have similarly shaped bells?
How does this affect the sound that each instrument produces?
What would an oboe with an onion-shaped bell sound like?
and what would an English horn with a bell-shaped bell sound like?
(and why is this presumably undesirable?)