Reed strength refers to its resistance to bending, or in other words, how much it resists the player’s breath.
This directly affects the playing experience: A harder reed (higher number) requires more energy. A softer reed (lower number) offers less control.
The key factor is the player’s own energy.
If you become breathless or fatigued after a few notes, the reed is clearly too hard. Conversely, if the sound becomes uncontrollable, too bright, or unstable, the reed is too soft.
At Henri SELMER Paris, strength ranges have been refined and divided into quarter strengths, offering greater consistency within a box and helping musicians find reeds better suited to their playing style.