My wife is struggling with stress and depression and would like to listen to “Accapella” , i.e. the singing without musical instrument accompaniment, during the 9 days. Is she allowed?
This is certainly permitted.
The decree against music in the Nine Days derives from the prohibition against joyful events of dancing and merrymaking, and music that is required for therapeutic purposes is not included in the prohibition.
For an article explaining the principles of music in the Three Weeks, please seen here.
Best wishes, and I hope that the condition will improve soon.