A headphone earcup (118, 118-1, 118-2, 418, 618, 718, 818, 1018, 1118, 1218), comprising: a cover support (429, 629, 729, 829) forming an ear pad; a coupling member (431, 631, 731, 831) configured to couple the earcup to an acoustic assembly housing (124, 124-1, 124-2, 424); and a seamless three-dimensional knit cover (428, 628, 728, 828) coupled to the coupling member, the knit cover defining an annular cavity and coupled to the ear pad such that the cover support is disposed in the cavity, the knit cover formed from a continuous contoured fabric of interlocking yarn and comprising: an outer portion (134, 434, 634, 734, 834) configured to have a first acoustic transparency value; an inner portion (236, 436, 636, 736, 836) forming a side wall of a sound hole (219, 419, 619, 719, 819) and configured to have a second acoustic transparency value; and an intermediate portion (138, 138-1, 138-2; 438, 638, 738, 838) configured to have a third acoustic transparency value, the intermediate portion extending between the outer portion and the inner portion, and defining a perimeter of the sound hole, wherein the first acoustic transparency value is different than at least one of the second acoustic transparency value or the third acoustic transparency value; wherein the intermediate portion has a different stiffness than at least one of the inner portion and the outer portion, and wherein the different stiffness is due to at least one of a different knit pattern and a different fabric material. a cover support (429, 629, 729, 829) forming an ear pad; a coupling member (431, 631, 731, 831) configured to couple the earcup to an acoustic assembly housing (124, 124-1, 124-2, 424); and a seamless three-dimensional knit cover (428, 628, 728, 828) coupled to the coupling member, the knit cover defining an annular cavity and coupled to the ear pad such that the cover support is disposed in the cavity, the knit cover formed from a continuous contoured fabric of interlocking yarn and comprising: an outer portion (134, 434, 634, 734, 834) configured to have a first acoustic transparency value; an inner portion (236, 436, 636, 736, 836) forming a side wall of a sound hole (219, 419, 619, 719, 819) and configured to have a second acoustic transparency value; and an intermediate portion (138, 138-1, 138-2; 438, 638, 738, 838) configured to have a third acoustic transparency value, the intermediate portion extending between the outer portion and the inner portion, and defining a perimeter of the sound hole, wherein the first acoustic transparency value is different than at least one of the second acoustic transparency value or the third acoustic transparency value; wherein the intermediate portion has a different stiffness than at least one of the inner portion and the outer portion, and wherein the different stiffness is due to at least one of a different knit pattern and a different fabric material. an outer portion (134, 434, 634, 734, 834) configured to have a first acoustic transparency value; an inner portion (236, 436, 636, 736, 836) forming a side wall of a sound hole (219, 419, 619, 719, 819) and configured to have a second acoustic transparency value; and an intermediate portion (138, 138-1, 138-2; 438, 638, 738, 838) configured to have a third acoustic transparency value, the intermediate portion extending between the outer portion and the inner portion, and defining a perimeter of the sound hole, wherein the first acoustic transparency value is different than at least one of the second acoustic transparency value or the third acoustic transparency value; wherein the intermediate portion has a different stiffness than at least one of the inner portion and the outer portion, and wherein the different stiffness is due to at least one of a different knit pattern and a different fabric material.