Help........most effective way to reduce noise from exhaust fans??????

Hello everyone, I have a veg and flower room in 2 separate areas. I have a 150mm inline fan exhausting both cabinets (veg room 3.5 x 2ft and flower room 2.5 x 4.5ft) both about 7ft high. now the fan is real loud, can here it a bit through my floors and i am wanting to reduce this as much as possible. have tried a homemade approach by adding insulation to the ducting and have lined my floor with insulation but can still hear the fan anyone got any ideas??? make a box and cover exhaust fan perhaps??? have seen the bungy style, but seems all the noise is from the "air in" of the fan not the "air out"???????????? someone help as I have a lot of people who stop by and dont want the noise to give me away.....................

well insulation would be my first peice of advice so since that didn't work perhaps you could get a seed control and turn it down a little or maybe you need a new fan. Good luck.

isolate it with some type of rubber , like the bungy cord you're talking about. Some photos would help.

Think about the use of weather stripping around the contact of the fan and the wall it is mounted on? Im not sure what your situation is but this could pose a minor solution. If it is the motor or the actual mechanical processes, its hard to confront. Of course trying to pinpoint the source of noise in important in this situation. Try getting some electric motor-friendly oil, or see about the condition of the bearings around the fan's axle if there is any? Duct taping stuff really tight or putting a constant hold on the structure is important and reduces vibration, try screwing or nailing boards with rubber or weatherstripping or heavy cloth on the side against the wall up you find leaning on the wall or putting a damper on the wall helps any. I hope these ideas spark new ones, I'm sure you've done alot to look into the noise.

Think on!! Peace tear!

thanks guys have read entire post on how to lower inline fan noises in the forums so am going to build a box around my fan, add 2" insulation, dry wall and egg cups suspended with bungees, my fan is new so dont think its the fan making the noises just the air intake is where it seems to come from. so will let you know if i succeed..............