What was the difference between haut and bas instruments in medieval Europe?

In medieval Europe, musicians often categorized instruments into two distinct groups based on their volume and intended setting: haut (meaning "high" or "loud") and bas (meaning "low" or "soft").1

• Haut instruments: These were loud instruments suitable for outdoor performances, ceremonial events, or seigneurial festivities. This category typically included wind and percussion instruments such as the shawm, bombard, trombone, organ, and various drums.21
• Bas instruments: These were soft instruments intended for indoor "room music." This category generally included stringed and quieter instruments such as the lute, viol, recorder, and harp.1

This classification helped medieval musicians select appropriate ensembles for different environments, ensuring that the sound was balanced for the occasion—whether it was a grand outdoor procession or an intimate indoor gathering. While these terms generally distinguished between loud and soft sonorities, the choice of instruments in practice often depended on the availability of performers rather than rigid rules.1