the yew hedges muffled the sound of the men’s footsteps

muffle v.
make the sound of sth quieter by wrapping it, covering it in
cloth,etc
包住（使声音低沉）

直译 紫杉树篱的阻隔使男人的脚步声变得低沉

所以也可以这样翻译
紫杉树篱中隐约透出了男人的脚步声