I’ve been thinking about the oboe family a lot lately. I made a realization about it recently. Actually, several realizations.
Number one: the Oboe itself has the smallest usable range of any woodwind instrument at only an two-and-a-half octaves. All other woodwinds have a minimum of three octaves (Bassoon and clarinets have at least three-and-a-half). But not the oboe.
Number two: the primary auxiliary instrument in each family is an octave higher or lower than the main instrument. The Piccolo is an octave higher than the Flute; the Bass Clarinet is an octave lower than the B-flat Clarinet; the Contrabassoon is an octave lower than the Bassoon. But not the Oboe. In fact, the Oboe’s primary auxiliary, the English Horn, is only a fifth lower. To further this, it doesn’t even make up a perfect fifth lower, but a diminished fifth – a tri-tone.
This means that the main oboe family’s range is just over three octaves – the same as any of the other woodwinds. This range is exactly the same range of the C Clarinet.
Here, I now ask the question, why is the English Horn the main auxiliary instrument and not the instrument built an octave lower than the Oboe: the Bass Oboe?
Before I go any further, it must be remembered that the Bass Oboe is a very rare instrument. Scoring for it is not wise unless you know the specific ensemble or player.
In a standard 3-member orchestral section, if we replace the English Horn with the Bass Oboe, the oboe section looks more like the other woodwind sections: 2 primaries and 1 auxiliary an octave apart from the primary. We now also have three-and-a-half octaves (plus) of oboe timbre.
We now have a much larger usable range. And the Bass Oboe fills in a gap in the woodwind family that is filled by no other standard instrument, a true tenor voice.
As the timbre of the Bass Oboe is not significantly different than the English Horn, we do not lose the mournful nature of the instrument. In fact, in this situation, the English Horn would become like the Alto Clarinet, not absolutely needed, but a nice filler.
If we look at things logically (which is never the best way to look at music – but still…), having an oboe section of 2 and a Bass Oboe would, on the surface, seem to be the most usable 3-person ensemble. That said, I only know a single piece, Grainger’s Children’s March (for band), that uses this ensemble.
At any rate, it’s an interesting thought experiment, and one that isn’t quite reasonable due to the rarity of the Bass Oboe.