Fine actuator reaction force cancellation flexible suspension

A hard disk drive (HDD) comprising:

• a disk stack comprising a plurality of disk media rotatably mounted on a spindle;
• a plurality of head sliders each housing a read-write transducer configured to read from and to write to a disk medium of the plurality of disk media;
• a first-stage actuator configured for moving the plurality of head sliders to access portions of the plurality of disk media;
• and
• a head stack assembly (HSA) coupled with the actuator, the HSA comprising:
• a carriage coupled with the actuator,
• a plurality of arms coupled to the carriage, the plurality of arms including an outer arm at each end of the disk stack and one or more inner arms between the outer arms, wherein each inner arm carries two suspension assemblies and each outer arm carries one suspension assembly, each suspension assembly comprising a corresponding fine actuator configured for moving a corresponding head slider of the plurality of head sliders to access portions of the corresponding disk medium, and
• a counter-suspension assembly coupled to a side of at least one outer arm opposing the corresponding suspension assembly, the counter-suspension assembly having a distribution of mass and a distribution of stiffness configured to counter multiple structural dynamics modes of the corresponding suspension assembly, wherein the distribution of mass within the counter-suspension assembly includes an interior cut-out from a main body of a counter-load beam of the counter-suspension assembly.