Practicing a musical instrument during the Three Weeks

Q: Is it permissible to practice music instruments during the Three Weeks?
A: Many authorities permit it since when a person practices he does not benefit from the music because his attention is focused on the precision of the actions involved. Some also explain that if someone does not practice for three weeks, he will begin to forget. It is therefore permissible to practice until Rosh Chodesh Av (see Pitchei Teshuvot 493:4 and 551:13).