The Effect of Lo-Fi Music Therapy on Pain Intensity and Blood Pressure in Post-Operation Patients in Karsa Husada Batu Hospital Muhammad Faizud Daroin*, Joko Wiyono S.Kep., M.Kes., Sp.Kom, Taufan Arif S.Kep., Ns., M.Kep, Anggun Setyarini S.Kep., Ns., M.Kep Abstract Background: Pain is the most common complaint and the main problem