I can't really notice it myself having lost that range of hearing year ago, but my kids tell me that my CGA monitor is MUCH louder/more annoying than the handful of VGA crts I've been tinkering with.
Is CGA more likely to be noisy in this way than VGA/EGA/etc?
Is there anything that can be done to reduce the noise?
CGA is a 15.7khz refresh rate which is in the range of human hearing. 31khz for VGA is well outside it. What they hear is the switching noise as the gun moves back and forth across the screen.
That's what I was just pondering, must be the lower CGA frequency.
I'll probably switch to a VGA monitor with mce2vga rather than CGA to make them happy...
Yep, CGA hsync is 15.7khz and that is identical to what a standard television uses.
You could try using an MDA monitor instead if you want to stick to something that's appropriate for the era: the hsync frequency is 18.4khz and could be just high enough to be inaudible for you and the kids.
I find the 15.7khz whine quite noticeable [even from an adjoining room!] but the 18.4khz whine is hardly audible (to me).
EGA is even higher (21.8khz) in the 350-line modes but drops back to standard 15.7khz for the 200-line modes that most EGA games use.
I will keep the cga monitor as primary but picked up a 9 pin switch box I will use to swap over to a small lcd vga panel with mce2vga adapter if the kids are in the bonus room.