Ceiling Exhaust Fan -How loud is .5 sones?

Panasonic has a very nice poop fan extractor rated at 3 sones and then they have the very same fan listed as a retro model thats 4 sones. Depends how and on what material the same fan is mounted. Yours for only 399,95. The same fan will have a different sound in a different room depending on size and material build out. Tom

Thanks Aby,
Since I wanted to avoid ANY unwanted sound in my HT room, the design that you mentioned (relocate the fan futher away) was first on my drawing board. But if .5 sones is an exeptional number, then I can live with it. Problem is, what is .5 sones equivalent to realife example?
This is what you are talking: http://www.youtube.com/watch?v=B-qWg60xFtY

Forget Sones those are all WAY to loud - sound like jet engines. You need something with DbA of around 10 at one meter (a big very slow moving fan if you want to move a lot of air). You can hear about 15 to 30 db below the noise floor and this means you will hear any and I mean any bathroom type evacuation fan.

You will need to go custom, IMHO.

Here is a Calculator

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.