exit of the air flow from the plenum and or into the adaptor and or tubing for example in some embodiments as the distance shrinks or narrows the noise level increases and may become a distraction in some embodiments a distance between 3 and 6 inches may be preferred but the distance may be varied in accordance with other factors another factor influencing and or affecting airflow and noise is the positioning of the adaptor 84 relative to the free edge 82 in some embodiments the adaptor 84 can be placed or positioned with its long axis i e along opening 90 parallel to the free edge 82 e g see fig9 thereby contributing to a quiet evacuative airflow the adaptor may be placed and or oriented otherwise too e g perpendicularly see e g fig1 and this may influence noise levels produced by the airflow it should be appreciated the shape size and location of components and or their composition and or flow rates and or pressure gradients may be selected to sonically tune optimize and or balance evacuative flow and noise fig4 and 6 depict another embodiment of the smoke evacuator vacuum head 18 of the present invention wherein the vacuum.