Hear one writes more ! Percussion produces a sound with a Bang

Dear why for instance when compatibility with other applications ( e.g. synht mastervplayer ) playing during recording, all synchronized and enters a stroke, but records not getting into the rhythm and notes? Tried everything cant do anything, so what I hear during the performance was recorded also! Percussion produces a sound with a Bang

Sata77 about GarageBand, v2.2.1