Siach HaSade h are among the elite vanguard of jazz-inclined improvisers breathing new life into otherworldly old Hasidic melodies from centuries past. The Quebec-based band further distinguish themselves with their many haunting diversions into moody, mystical Middle Eastern sounds. Their latest album Song of the Grasses, a collection of exquisitely sad songs, exquisitely played, is streaming online , and the band has a whirlwind New York tour coming up. On March 4 they’ll be doing a set (plus a jam afterward) at the Stephen Wise Free Synagogue, 30 W. 68th St. at 7:30 PM; cover for the show is $15, more if you want the dance lesson or whatever else is happening beforehand, usually a lot at this place. Siach HaSadeh are also at Branded Saloon in Ft. Greene at 8 on March 5 followed at 9 by the more boisterous Breslov Bar Band . Then on March 6 they’ll…