Yes, it is true that the Bass is the largest member of the Violin Family, but as you learned earlier, the Modern-day Bass is also a product of the influence of the Gamba Family. That is why the Bass has sloped-shoulders!
We are calling the instrument the Bass, and V shared a presentation in which he placed the Bass in the Violin Family. Several of my maestros shared the info that the Bass has been called the Stand-Up Bass and other names. It is helpful to study the value of the term Stand-Up.
There are several names for the Modern-day Bass.
They are the: Stand-Up Bass, Contrabass, Double Bass, Bass Violin, and Upright Bass.
I was taught that the reason that the shoulders on the bass are sloped is because bass players always have looked for common sense, practical, solutions to playing-position challenges, including changing the shape of the instrument.
The bass has a lot of physical territory that players need to travel while performing successfully. The bass requires players to navigate a vast terrain of string length in order to play notes in all ranges.
Luthiers were always changing and improving the shape of the body of the instrument in order to make it easier and smoother for the player’s arms, hands and body to perform successful playing motions. Experimentation with the design of the bass went on for several centuries and continues today!