A:Answer Hi GrassCutter, The noise canceling function is most effective in low-frequency ranges such as airplanes, trains, offices, near air-conditioning, and is not as effective for higher frequencies, such as human voices. The WF-1000XM3s should be able to lessen the sound of the lawnmower and make that task more enjoyable for your husband. For the noise canceling function to be fully effective, we highly recommend following the guide here: https://helpguide.sony.net/mdr/wf1000xm3/v1/en/contents/TP0002392265.html. Thanks! -Vincent