with attention to the perspective view of fig1 , an air drill diffuser 10 of the invention is shown as it appears when mounted to a typical tractor drawn air drill assembly 12 . the air drill assembly 12 typically includes a trailer storage bin 14 having fertilizer and seed compartments or hoppers 16 and 18 . the seed is delivered from the seed compartment 18 to a primary air and seed distribution manifold 20 and conveyed as an airborne particulate through several feeder conduits 22 to a trailer drawn planter framework 24 . the framework 24 is typically mounted to follow the bin 14 and one or more arms or wing frames 26 are hinged to pivot about the framework 24 . multiple planter opener arm assemblies 50 having fertilizer and seed distribution ports in turn are supported to the wings 26 . the fertilizer is independently distributed from the fertilizer compartment or hopper 16 to a separate primary fertilizer distribution manifold 20 and separate feeder conduits 22 to the planter framework 24 . the seed and fertilizer feeder conduits 22 extend along the planter framework 24 and the hinged wing frames 26 where the conduits 22 couple to lower ends of several secondary seed and fertilizer distribution manifolds 28 . the fertilizer and seeds are injected into the bores of “ j - shaped ”, tubular columns 30 at the manifolds 28 and subjected to contact with several dimpled protrusions 32 that project into the bore 34 of each column 30 to reduce the velocity and separate and agitate the fertilizer and seeds as the fertilizer and seeds rise in the columns 30 . in particular regard to the seeds and after being agitated by the protrusions 32 , the seeds rise to a distribution head piece 36 . the head piece 36 contains a ring shaped separator having several vertical vanes . as the seeds rise in the bore 34 they are randomly distributed between the internal vanes . the vanes are aligned to associated outlet ports 42 formed at a rubber ring or seal piece 44 mounted in concentric relation to the internal vaned separator . the primary flow of air and suspended seed is thus diverted into the ports 42 and associated seed delivery conduits 48 that extend to individual opener arm assemblies 50 that each support an individual planter head or seed boot . the opener arm assemblies 50 are supported to the wing frames 26 at an appropriate spacing set for the type of seed being planted . fertilizer is separately conveyed from other secondary distribution manifolds 28 to the seed boot of each opener arm assembly 50 and a prepared furrow . each opener arm assembly 50 independently receives and dispenses an appropriate amount and type of fertilizer for the seed being planted . the air directed fertilizer is conveyed through a fertilizer conduit 52 to a distribution tube 54 , see fig2 . the fertilizer tube 54 is placed behind an opener head 56 which forms a planting furrow and into which the fertilizer is deposited to an appropriate depth . a seed placement or planting head 58 is independently supported to each opener arm assembly 50 behind each opener head 56 and fertilizer distribution tube 54 . the depth of the head 58 is set to assure proper placement of gravitationally fed seed . seed distributed by each secondary manifold 28 is conducted into and through the seed conduits 48 to the seed diffusers 10 of the invention and deposited from a seed placement boot 60 . as the air and seed enter each diffuser 10 , the seed is caused to contact and ricochet or deflect back and forth between included valve pieces and the conveying air is simultaneously bled off . ultimately the air is completely bled off and the seed collects and is momentarily supported on a seed support ledge 112 ( e . g . half - moon shaped ) inside the diffuser 10 before falling at a generally singular rate through the seed placement boot 60 under the force of gravity into a prepared furrow . at least one presser wheel 62 typically follows each planting head 58 to close each furrow over the deposited fertilizer and seed . the spacing between seeds is thereby primarily determined by the towed velocity over ground of each opener arm assembly 50 . with the aid of the diffuser 10 , the air drill planting assembly 12 provides a relatively controlled , gravity placement of the seed without problems of seed fracture ( e . g . cracking or splitting ) and / or seed scatter . that is by dissipating the distribution air in the diffuser 10 , the seeds fall at a generally uniform rate and equal spacing to a pre - established depth for optimal soil / seed contact . seed spacing is also dependent upon the towing speed of the opener arms 50 , while proper placement depth is established at the furrow opener 56 and mounting height of the seeder head 60 relative to opened furrows . the seed falls from the seeder head 60 and provides for a gravity distribution of the seed without bounce or scatter and unaffected by the distribution air . with attention to fig3 through 5 details to the construction applicant &# 39 ; s diffuser 10 are depicted . the diffuser 10 is particularly shown in assembled and exploded assembly . each diffuser 10 generally provides a tubular housing 70 constructed from two mating or overlapping side wall or shell pieces 72 and 74 . rivets or other fasteners ( not shown ) secure the side wall pieces 72 and 74 together at tangs 76 that project from the shell pieces 72 and 74 . upstream / inlet and downstream / outlet ports 78 and 80 are configured and sized in the internal ends of the mated shell pieces 72 and 74 . the ports 78 and 80 interconnect and mate with specific seed conduits 48 ( e . g . 1¼ or 1½ inch ) provided at commercial planters 12 . the diffusers 10 are designed to mount as either before or after market accessories to each opener arm assembly 50 . upon inserting the upstream and downstream cut ends of each conduit 48 into the ports 78 and 80 , the conduit 48 is gripped by several ringed ridges 82 or other devices to capture the diffuser 10 to the conduit 48 . the ports 78 and 80 and ridges 82 are sized and shaped to facilitate a secure fastening of the diffuser 10 relative to the operating environment and conditions . appropriate fasteners ( e . g . screws ) are also inserted through raised hubs 84 at the housing side wall 72 to secure the inlet and outlet ends of the diffuser housing 70 to the conduits 48 . although one form of attachment and fastening of the housing 70 to the conduits 48 is shown , a variety of other couplings and fastenings can be used to physically secure each housing 70 to appropriate air and seed delivery conduits . mounted at the upstream or forward end of a cylindrical cavity , bore or channel space 86 within the housing 70 is a resiliently mounted valve piece 88 . the valve piece 88 is particularly hinge mounted . the valve piece 88 provides a leading seed deflecting arm portion 90 and a counter weight lagging arm portion 92 . the arm portions 90 and 92 extend at an angular orientation “ a - a ” in the range of 10 to 25 degrees relative to each other . an intermediate fold or bend 94 separates the leading and lagging arm portions 90 and 92 and permits the valve piece 88 to pivot at the fold 94 about a leading edge 102 of a screened fulcrum piece 96 . the length and weight of the lagging counter weight arm portion 92 relative to the leading deflecting arm portion 90 determines the degree of resilience exhibited by the valve piece 88 . the angle “ a ” between the leading and lagging valve arm portions 90 and 92 is sized to provide free movement of the valve piece 88 as it pivots about the upstream edge 102 of the fulcrum / screen piece 96 . the fold 94 is supported on the edge 102 of the fulcrum / screen piece 96 and thus the lagging counter weight arm portion 92 is free to pivot about the edge 102 of the intermediate fulcrum / screen piece 96 in the space between the fulcrum / screen piece 96 and the internal surfaces of the side wall piece 72 . a stop member 103 projects interiorly from the shell piece 70 to limit the range of movement of the downstream end of the counter weight arm portion 92 . the screened fulcrum piece 96 is constructed from a length of screen that extends in the cavity space 86 at an acute angle relative to the side wall piece 72 as the screen 96 projects downward toward the outlet port 80 . the upstream edge 102 of the fulcrum / screen piece 96 particularly extends from between lateral supports 98 that project from an interior surface of the side wall piece 72 in the cavity space 86 . the fulcrum / screen piece 96 depends at an increasing angular orientation as it extends to rest on other downstream projections or supports 99 and a baffle or gate flange 100 adjacent the outlet port 80 of the cavity space 86 . the downstream edge 101 of the fulcrum / screen piece 96 is supported on the baffle flange 100 interiorly of the diametric center of the housing 70 , see fig3 . the baffle flange 100 also prevents seed from collecting behind the fulcrum / screen piece 96 . the fulcrum / screen piece 96 is typically mounted to extend at an acute angle in a range of 10 to 30 degrees relative to the side wall piece 72 . several longitudinal vents or relief ports 104 are let through the side walls of the shell piece 72 . the ports 104 extend longitudinally adjacent the counter weight arm portion 92 and fulcrum / screen piece 96 . air entering the housing 70 with the seed is vented through the pores of the fulcrum / screen piece 96 and the ports 104 . the screen 96 presently exhibits a mesh or grit porosity in the range of 1 / 32 nd ( 0 . 03125 ) to 5 / 32 nd ( 0 . 15625 ) inch at each pore . screening with other mesh or grit sizes can be used depending upon the seed size to prevent venting the seed from the housing 70 as the air is dissipated . if the screen pores are too small the pores will clog with fertilizer dust and not vent properly . although the relief vents 104 presently only extend along the length of the counter weight arm portion 92 , more or less vents 104 can be provided and aligned as desired to the included valve piece 88 and fulcrum / screen piece 96 . returning attention to the upstream seed deflecting arm portion 90 of the valve piece 88 , it includes a secondary bend or downstream tail piece end 106 that extends into the bore of the cavity space 86 approximately to the diametric center . the tail piece 106 projects at an angle “ b ” in the range of 10 to 25 degrees from an upstream upper arm piece 108 of the seed deflecting arm portion 90 . the angles “ a ” and “ b ” are established to assure contact between the entering seed with the deflecting arm portion 90 . the relative angles “ a ” and “ b ” and lengths of the arm pieces 106 and 108 and valve arm portions 90 and 92 are established to provide a desired resilience at the hinged valve piece 88 to prevent damaging the seeds as they engage the valve piece 88 . the type of material ( s ) from which the valve piece 88 and fulcrum / screen piece 96 are constructed is selected to withstand the abrading effects of the high velocity seed as it encounters the valve and screen pieces 88 and 96 . although a counter weight arm portion 92 is provided and has proven effective , the material used to construct the seed deflecting valve piece 88 and fulcrum piece 96 can be selected and / or the valve piece 88 can be shaped to exhibit an intrinsic resilience . a resilient spring member may also be mounted between the arm portion 92 and the housing side wall 72 . additional bends or resilient extensions may also be included at the seed deflecting valve piece 88 to provide desired seed deflection angles and resilience . ideally the seed deflecting valve piece 88 is resiliently suspended in a fashion somewhat akin to a reed valve to avoid fracturing the seed as the air is vented from the housing 70 . as described above the seed deflecting valve piece 88 and fulcrum / screen piece 96 are mounted to the longitudinal or side wall shell piece 72 of the housing 70 . with attention to fig5 , the adjoining side wall or shell piece 74 includes a second valve piece 110 . the valve piece 110 is also resiliently mounted and positioned like a second reed valve to deflect seed between the valve pieces 88 and 110 to dissipate energy . a downstream portion 109 of the valve piece 110 extends at an acute angle “ c ” in the range of 10 to 30 degrees relative to the interior surfaces of the shell piece 74 toward the diametric center of the housing 70 . a downstream edge 111 of the second valve piece 110 terminates before intersecting the valve piece 88 and / or above the adjacent edge 101 of the fulcrum screen piece 96 and just short of the diametric center of the cavity space 86 . a gap is thus formed in the central region of the bore space 86 between the downstream edges 101 and 111 of the seed deflecting valves 88 and 110 and through which the seed falls after the air is vented . a forward or upstream end 113 of the valve piece 110 is rigidly fastened to the side wall 74 and the unsupported downstream end 109 resiliently flexes in the housing 70 . the angular extension of the valve end 109 thus exhibits an inherent resilience . seed initially deflected by the pivoting valve piece 88 upon entering the cavity space 86 is directed to impinge onto the second valve piece 110 . the flexion and angular orientation of the second valve piece 110 re - directs the seed back against the valve piece 88 or the fulcrum / screen 96 . the back and forth ricocheting effects of the valve pieces 88 and 110 and simultaneous venting of the conveying air completely reduces the velocity of the seeds such that the spent seeds generally exhibit zero velocity and gravitationally fall at a generally singular rate from the outlet port 80 . it is to be appreciated the resilience of the valve piece 110 can be varied with different mountings or the use of different materials . the valve piece 110 might also be constructed of a porous material to vent air . the fulcrum piece 96 might also merely comprise a pivot member about which the valve piece 88 pivots . the counter weight arm portion 92 might also be mounted to deflect seed onto the valve piece 110 . as the spent seeds pass the distal end of the fulcrum / screen 96 and downstream edge 111 of the second valve piece 110 , the seed momentarily falls to collect on a flange or ledge 112 that projects into the cavity or bore space 86 . the ledge 112 interrupts the seeds &# 39 ; passage through the housing 70 and causes a small amount of seed to collect at the ledge 112 . the seed eventually randomly falls at a generally singular rate from the ledge 112 and through the seeder head or boot 60 . the displacement between the dispensed seeds generally depends upon the speed of the planter arm . a farmer is however assured that un - fractured seed is dispensed into and not outside the furrow . while the invention has been described with respect to a presently preferred assembly and considered improvements , modifications and / or alternatives thereto , still other assemblies and arrangements may be suggested to those skilled in the art . it is also to be appreciated that the features of the foregoing diffuser housing assembly can be arranged in different combinations . for example , the valve pieces 88 and / or 110 can be constructed to provide a variety of different resilient mountings that promote deflection and energy dissipation . the foregoing description should therefore be construed to include all those embodiments within the spirit and scope of the following claims .