No, only one Hum Removal-TDM module may be placed in Learn mode at a time. Learning the same hum-type noise on more than one track can be accomplished by placing Pro Tools in Loop mode, isolating a section of the undesired hum (which must be larger than 0.5 seconds), making a selection and looping it during Playback. Separate Learn processes may then be performed on the original and subsequent Hum Removal modules during playback.