Abstract: A Helmholtz damper system includes damper element(s) that include a tube positioned in a hollow mount in a cap assembly of a combustor. The hollow mount has an aft end in fluid communication with a combustion chamber. The tube has a hollow body having an aft end in fluid communication with the combustion chamber, a forward end, and a volume therein. A damping volume control member is coupled to the tube and has a perforated member positioned to at least partially define a damping volume. The damping volume may be defined between the perforated member and another perforated member at the aft end of the tube or just within the control member. The damping volume controls a frequency dampened by the damper element and can be adjusted to the exact frequency requiring damping by adjusting the control member size and/or shape.