Units used to measure loudness are Sone (loudness N) and Phon (loudness level L). 40 Phons = 1 Sone. Scroll down to related links and look at "Loudness - Wikipedia" and "Sound level change and the change of the respective factor of volume and loudness"

Loudness is the quality of a sound that is the primary psychological correlate of physical strength or amplitude. Loudness is a subjective felt impression and is in some way related to the objective measure of the sound pressure. Neither our ear drums nor the microphone diaphragms can convert acoustic intensity. Therefore only use the sound pressure for measuring. To measure the loudness feeling is a difficult thing. The loudness of 1 sone equals the loudness level of 40 phons (at 1 kHz).

Loudness is the quality of a sound that is the primary psychological correlate of physical strength or amplitude. Loudness is a subjective felt impression and is in some way related to the objective measure of the sound pressure. Neither our ear drums nor the microphone diaphragms can convert acoustic intensity. Therefore only use the sound pressure for measuring. To measure the loudness feeling is a difficult thing. The loudness of 1 sone equals the loudness level of 40 phons (at 1 kHz).

The loudness of 1 sone equals the loudness level of 40 phons (at 1 kHz). Loudness is the quality of a sound that is the primary psychological correlate of physical strength or amplitude. Loudness is a subjective felt impression and is in some way related to the objective measure of the sound pressure. Neither our ear drums nor the microphone diaphragms can convert acoustic intensity. Therefore only use the sound pressure for measuring. To measure the loudness feeling is a difficult thing.

To change the loudness on a clarinet you can change the reeds which come from 1-5, 1 being the easiest reed to play and 5 being the hardest to play.