Gothic/weird fiction story about experiments into synchronising voice frequencies to magical effect
I remember reading half of this story and putting it down, meaning to come back to it, but now I can’t remember where I was reading it or what it was called!
I recall it having a possibly Victorian era setting, a young man of decent education but little money being asked to come to a remote house in the (British?) countryside, where a large and charismatic older man pays him to stay and take part in experiments to do with sound frequencies and the human voice. Also living there are an older (mostly deaf?) woman working as a servant, and a young woman the protagonist takes a fancy to. But he soon finds himself disturbed by the experiments, wherein the sounds produced seem to have an effect on his perception or reality, and he starts hearing noises outside his door at strange hours.
Possibly the story was leaning towards Enochian ideas, recreating the language or sound of Angels/God to take control of creation/reality?
Thanks in advance!