Been getting this exact thing for the past few months actually. Deep male voice, always the same word or phrase, never anything else. Mine sounds like it's saying "below" but honestly could be something else depending on how I play it back.
What word are you getting? That's the part that interests me most. Repetition like that feels different from random noise, it's like something's trying really hard to get one specific message across and hasn't worked out how to say anything more.
I record in my back garden mostly and also once in the old churchyard near Wareham. Got it in both locations which surprised me. I'd ruled out it being tied to a particular place.
Would love to hear your actual recording if you're willing to share.