I've recently purchased a CM320TD and have noticed it makes quite an irritating buzz, that's audible from the graders and client's chair. I'm used to BVMs having a subtle fan noise, but the buzz with the CM320TD is in the "sawtooth" higher frequency range and is much louder. Clients notice it, it sounds like an angry bee! We've tried the LM24 and it doesn't have it.
I contacted FSI and they said that the blacklight will give off some buzz, especially when turned down, but at all backlight levels the buzz is present on my unit. There is no way I can compare my monitor with another one to see if my monitor is faulty, as I'm in Australia.
So I was hoping that someone with a CM320TD could let me know if they can hear the same buzz?
The unit should go essentially quiet at a backlight setting of about 70 to 75 (varies a bit from unit to unit), if not you can certainly request an RMA for a replacement if you like from our support department. At levels below this there will be a bit of subtle buzz that comes from the panel.
The noise does come from the panel itself when run at lower backlight levels and this is largely out of our control (e.g. any other manufacturer using this particular LCD panel would get the same noise at similar backlight levels). We've discussed this extensively with our panel supplier and while they do standby this being a normal characteristic they have also promised to look into it more closely and see if possible workarounds can be found to allow their LCD panels to run more quietly. If such workarounds are provided we will do our best to implement them via updated firmware.
Again though, if it does not basically go away at a backlight setting of 75 that would be outside of normal thresholds (unlike other units) and a replacement may be in order.