Ceiling Exhaust Fan -How loud is .5 sones?

Here's some info....

http://www.sengpielaudio.com/calculatorSonephon.htm

I run a whisper fan that is rated at about 30db,too lound. So I have reduced the fan speed in half and sitting 4ft away i can barely hear it.

If I read the graphs right .5 sone = 30 phons which in db level would be about 30db. I think you need to put a potentionmeter on this fan and reduce the speed in half.

Does it have to run while listening/watching, or can it be turned on and then back off, or during some other times?

Noise then wouldn't be as integral an issue.

Insulating the housing the fan would reside in would attenuate the sound... like a whisper box for a projector or what ever they call that added box surrounding the PJ.

Speaking of which, with the lamp turned up to full brightness I can hear the PJ runing... until I turn up the sound of the whatever... Flick, CD, etc. Then of course, the noise is not a consideration.

Adding to the insulation of the fan housing, or even setting it into a duct work which turns by 90 degrees should also diminish the noted or audible sound of the motor itself. Further lengthening the ducting, and thereby removing the fan still farther away will surely decrease the noise it makes.

Go with a large register as you can too. that will help.

Good luck.

BJ,
Yes,the exhaust fan must run when the system is on to get the heat up on attic. Reason I'm looking for maximum quiteness is because I listen to soft music on low volume normally at 2 to 4am. So basically, at these hours, I will hear everything else as well.
I just read an DIY article about an exhaust fan with .5 sones and the author gave a real life example: In his bedroom, the fan ran very quite that he was 10' away and he couldn't tell if it was On or not. That's a very good info for me.

I just read an DIY article about an exhaust fan with .5 sones and the author gave a real life example: In his bedroom, the fan ran very quite that he was 10' away and he couldn't tell if it was On or not. That's a very good info for me.

The guy is either deaf or he lives 200 feet from a major highway. O.5 Sones is loud.

Is your attic finished? If not, I would mount the fan in the attic (not in the ceiling of your listening room) on top of the joists - utilizing good damping material between the fan and the joists (do a search for after-market noise isolation mounting materials/products). You can easily construct a duct between the fan and the ceiling of your listening room -which can also be damped (provided that you don't obstruct air flow). The duct work must be air-tight to insure maximum ventilation – I would suggest avoiding metal/tin duct work, as it is noisy (MDF may be a better solution. Make sure you damp the duct work from the fan, as the ductwork can act like a speaker cabinet – projecting the sound back into your room. This will not eliminate all of the mechanical noise, but it will reduce the noise compared to mounting it directly in your ceiling.

Note: you can also tweak the fan itself with damping materials (i.e.: soft fan/motor mounts, silicone motor mounts, etc.). The thing is, you want to decouple the fan from the mounting area (in this case your house).