If your fan is fitted into the ceiling itself then there's not a lot you can do about it, the fans motor is whirring away above your head and you need a dense barrier or plenty of airspace between that and your ears for you not to hear it.
Here's a solution for inline fans.
Make a 'box within a box'... same principle of soundproofing studios (room within a room)
Basically make an mdf box (with lid) around the fan, drill holes for the ducting at either end, line it with rockwool. Make another bigger box to house the 1st box, drill holes for the ducting at either end, also line that with rockwool, and place the 1st box inside the 2nd, so that all 6 sides are in contact with the rockwool. Stick the box anywhere you like, the insulation will dampen any vibes.
You can hard fix the fan inside the first box using builders band.
It doesn't matter if you can't get hold of rockwool, use normal fluffy insulation, just don't pack it in too tightly.
If you want to also silence the noise of the fan motor itself, then attach the ducting to the outer box only, and carve a hole through the insulation so that the airflow passes freely between the 2 boxes. The bigger this gap, the quieter it will be.
Be sure to make the inner box big enough to fit the fan inside, with an airspace between it and all the insulation. Also use 18mm MDF, and mount the whole lot as far away from your bathroom vent as possible.
Here's a solution for inline fans.
Make a 'box within a box'... same principle of soundproofing studios (room within a room)
Basically make an mdf box (with lid) around the fan, drill holes for the ducting at either end, line it with rockwool. Make another bigger box to house the 1st box, drill holes for the ducting at either end, also line that with rockwool, and place the 1st box inside the 2nd, so that all 6 sides are in contact with the rockwool. Stick the box anywhere you like, the insulation will dampen any vibes.
You can hard fix the fan inside the first box using builders band.
It doesn't matter if you can't get hold of rockwool, use normal fluffy insulation, just don't pack it in too tightly.
If you want to also silence the noise of the fan motor itself, then attach the ducting to the outer box only, and carve a hole through the insulation so that the airflow passes freely between the 2 boxes. The bigger this gap, the quieter it will be.
Be sure to make the inner box big enough to fit the fan inside, with an airspace between it and all the insulation. Also use 18mm MDF, and mount the whole lot as far away from your bathroom vent as possible.
