Thanks to alex10 and his idea that give me inspiration to build my own sound suppression for exhaust fan. And I thought main while I'm making it will make some foto's and share it with all of you.
First of all you will need a box, I took 1 from my clip fan. Make it airproof by scotching it (hhhmm not drinking scotch
but use this ) and don't miss any spot of the box otherwise it would not be airproof and exhaust power will be lost.

2-nd is : Take some acoustic foam can find it in DIY store near you. Cut it and place in the box.

You will also need some tools.

3-th : place Flexible Ductwork on the box where you will cut hole for and use black marker or something else to have needed diametre for cutting.

4: Now you can take circle you cut before and make it a little bit smaller than it was,and it will be perfect tool to help you cut a circle from acustic foam, like this.It will cut some fan noise as well.

Check if it is ok

5: Now you can recicle some of the foam left after cutting from step 2 and 4 and place it in tube like this
.
6: Now the trykiest part as you need to duct fan to the tube and make it airproof. Need a lot of scotch and some other tape as well. Also need one little hole for electrical cable and bigger one for air to be sucked in (the size of it depends on your need). Also you can live if your exoust is strong anought or remove it.

7: After this is done place in the box and cover with some foam and close the box

8: Now some more tape from outside to make it fully airproof.

When the job is done it can be placed in your growroom

And here is my babies
not disturbed by mega sound of fan

Check the sound it makes now
http://www.yapfiles.ru/show/387250/2006f8272fb20f070e6df7605bc4d670.flv.html
Credits go to alex10 as he motivated me to make this little diy :clap:
First of all you will need a box, I took 1 from my clip fan. Make it airproof by scotching it (hhhmm not drinking scotch


2-nd is : Take some acoustic foam can find it in DIY store near you. Cut it and place in the box.

You will also need some tools.

3-th : place Flexible Ductwork on the box where you will cut hole for and use black marker or something else to have needed diametre for cutting.

4: Now you can take circle you cut before and make it a little bit smaller than it was,and it will be perfect tool to help you cut a circle from acustic foam, like this.It will cut some fan noise as well.

Check if it is ok

5: Now you can recicle some of the foam left after cutting from step 2 and 4 and place it in tube like this

6: Now the trykiest part as you need to duct fan to the tube and make it airproof. Need a lot of scotch and some other tape as well. Also need one little hole for electrical cable and bigger one for air to be sucked in (the size of it depends on your need). Also you can live if your exoust is strong anought or remove it.

7: After this is done place in the box and cover with some foam and close the box

8: Now some more tape from outside to make it fully airproof.

When the job is done it can be placed in your growroom

And here is my babies

Check the sound it makes now
http://www.yapfiles.ru/show/387250/2006f8272fb20f070e6df7605bc4d670.flv.html
Credits go to alex10 as he motivated me to make this little diy :clap: