Sounds like you need new fans or a fan hub that can go to zero. I would consider fans first I think. I’d wonder about fans that were still audible and unpleasant at something as low as 23%. Not knowing what fans you have, I’d expect most fans to be somewhere around 400 to 600rpm at 23%. Many good fans are inaudible at those speeds. Which makes me consider new fans, especially if you’re sensitive to noise.