An air filtration media pack (301, 302, 402, 502, 602) comprising: (a) a plurality of layers of single facer media (5, 117, 137, 147) wherein the layer of single facer media comprising a fluted sheet (3, 43, 70, 80, 90, 112, 122, 142), a facing sheet (4, 44, 72, 73, 82, 83, 92, 93, 111, 113, 121, 123, 141, 143), and a plurality of flutes (11, 15) extending between the fluted sheet and the facing sheet and having a flute length extending from a first face (304, 414) of the filtration media pack to a second face (306, 416) of the filtration media pack, wherein the fluted sheet comprises repeating internal peaks (114, 116, 124, 144) facing toward the facing sheet and repeating external peaks (115, 119, 125, 145) facing away from the facing sheet; (b) a first portion of the plurality of flutes being closed to unfiltered air flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered air flowing out of the second portion of the plurality of flutes so that air passing into one of the first face or the second face of the media pack and out the other of the first face or the second face of the media pack passes through media to provide filtration of the air; characterized in that (c) the fluted sheet includes a repeating pattern of flutes comprising a flute having at least one ridge extending along at least a portion of the flute length between an internal peak and an adjacent external peak; i. at least a portion of the plurality of flutes exhibit a volume asymmetry such that a difference between an upstream volume of the media pack and a downstream volume of the media pack is greater than 10%, and ii. the internal peaks or the external peaks or both (114, 115, 116, 119, 124, 125, 126, 144, 145, 212, 214) have a radius of less than 0.25 mm, and iii. comprising tapered flutes. (a) a plurality of layers of single facer media (5, 117, 137, 147) wherein the layer of single facer media comprising a fluted sheet (3, 43, 70, 80, 90, 112, 122, 142), a facing sheet (4, 44, 72, 73, 82, 83, 92, 93, 111, 113, 121, 123, 141, 143), and a plurality of flutes (11, 15) extending between the fluted sheet and the facing sheet and having a flute length extending from a first face (304, 414) of the filtration media pack to a second face (306, 416) of the filtration media pack, wherein the fluted sheet comprises repeating internal peaks (114, 116, 124, 144) facing toward the facing sheet and repeating external peaks (115, 119, 125, 145) facing away from the facing sheet; (b) a first portion of the plurality of flutes being closed to unfiltered air flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered air flowing out of the second portion of the plurality of flutes so that air passing into one of the first face or the second face of the media pack and out the other of the first face or the second face of the media pack passes through media to provide filtration of the air; (c) the fluted sheet includes a repeating pattern of flutes comprising a flute having at least one ridge extending along at least a portion of the flute length between an internal peak and an adjacent external peak; i. at least a portion of the plurality of flutes exhibit a volume asymmetry such that a difference between an upstream volume of the media pack and a downstream volume of the media pack is greater than 10%, and ii. the internal peaks or the external peaks or both (114, 115, 116, 119, 124, 125, 126, 144, 145, 212, 214) have a radius of less than 0.25 mm, and iii. comprising tapered flutes. i. at least a portion of the plurality of flutes exhibit a volume asymmetry such that a difference between an upstream volume of the media pack and a downstream volume of the media pack is greater than 10%, and ii. the internal peaks or the external peaks or both (114, 115, 116, 119, 124, 125, 126, 144, 145, 212, 214) have a radius of less than 0.25 mm, and iii. comprising tapered flutes.