I think it's pretty common for projectors to "squeak" or "ring" while they're starting up isn't it? My last Sony VPL-HW10 certainly did and this new JVC-DLAX35 does, but in my case switching to 24fps outputs a very specific tone that is completely constant and doesn't change volume over time, it's just there: "beeeeeeee" regardless of my position in relation to the projector. The only thing that seems to affect it is switching to High lamp mode & then back to Low as I mentioned before, then it seems to gain a stutter, so it sounds like a series of beeps: "beep, beep, beep" and on. The irony is that if it was occuring for 50fps/60fps material then I could learn to live with it, but 24fps basically means I have to sit through it for 90% of the things I use my projector for.
I'm gonna phone JVC on monday and see what they think of the issue, I really hope it is a specific problem as then it can actually be fixed, obviously if it is a general issue then it's going to be a lottery as to whether a replacement lamp or projector will share the issue or not.