A melt blowing die (520, 540, 600, 652, 702, 752), comprising: at least one stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) of plates (102, 202, 404) stacked in a stack direction (668, 718, 768), the stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) of plates (102, 202, 404) comprising: polymer filament extrusion orifices (104, 204) including at least one row of extrusion orifices (104, 204) extending in the stack direction (668, 718, 768) across multiple said plates (102, 202, 404) of the stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756); a gas distribution system within the stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) including gas outlets positioned to provide distributed gas flow to contact and attenuate polymer filaments extruded from the said extrusion orifices (104, 204) of each said row of extrusion orifices (104, 204); and at least one polymer distribution channel (108, 208, 410) extending longitudinally through multiple said plates (102, 202, 404) in the stack direction (668, 718, 768), the polymer distribution channel (108, 208, 410) being in fluid communication within the plate stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) for supply of polymer to the extrusion orifices (104, 204) of at least one said row of extrusion orifices (104, 204); and the polymer distribution channel (108, 208, 410) is open to receive polymer feed only at a longitudinal end of the polymer distribution channel (108, 208, 410). at least one stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) of plates (102, 202, 404) stacked in a stack direction (668, 718, 768), the stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) of plates (102, 202, 404) comprising: polymer filament extrusion orifices (104, 204) including at least one row of extrusion orifices (104, 204) extending in the stack direction (668, 718, 768) across multiple said plates (102, 202, 404) of the stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756); a gas distribution system within the stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) including gas outlets positioned to provide distributed gas flow to contact and attenuate polymer filaments extruded from the said extrusion orifices (104, 204) of each said row of extrusion orifices (104, 204); and at least one polymer distribution channel (108, 208, 410) extending longitudinally through multiple said plates (102, 202, 404) in the stack direction (668, 718, 768), the polymer distribution channel (108, 208, 410) being in fluid communication within the plate stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) for supply of polymer to the extrusion orifices (104, 204) of at least one said row of extrusion orifices (104, 204); and polymer filament extrusion orifices (104, 204) including at least one row of extrusion orifices (104, 204) extending in the stack direction (668, 718, 768) across multiple said plates (102, 202, 404) of the stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756); a gas distribution system within the stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) including gas outlets positioned to provide distributed gas flow to contact and attenuate polymer filaments extruded from the said extrusion orifices (104, 204) of each said row of extrusion orifices (104, 204); and at least one polymer distribution channel (108, 208, 410) extending longitudinally through multiple said plates (102, 202, 404) in the stack direction (668, 718, 768), the polymer distribution channel (108, 208, 410) being in fluid communication within the plate stack (100, 200, 402, 502, 522a, 522b, 542a, 542b, 602a, 602b, 602c, 602d, 656, 706, 756) for supply of polymer to the extrusion orifices (104, 204) of at least one said row of extrusion orifices (104, 204); and the polymer distribution channel (108, 208, 410) is open to receive polymer feed only at a longitudinal end of the polymer distribution channel (108, 208, 410).