Silencer position

[DoctorWho]

Post man dropped off an 8 inch silencer today and I'm wondering what the optimal position for it is.  I know it has to go after the exhaust fan but as I see it I have three options.  First is directly after the fan, second is half way into the ducting and lastly is having it at the very end.  As far as I can tell all come with advantages and disadvantages.  If its directly after the fan the air will hit it immediately but it then needs to do a 90 degree turn and go almost 3m through ducting so turbulence will have a greater chance of building up.  If its at the very end it will only get the last bit of turbulence which will still have the ducting vibrate making noise anyway.  The middle is a half way point between those two extremes and I'm thinking that it might be the best option for me but would like to get the advice of those with experience before setting it up.

 

I'm also interested in finding out if the type of ducting makes any difference to the position of the silencer or if its a one size fits all kind of deal.  I'll be upgrading to insulated ducting one day in the future as its obviously better than the standard stuff I'm using now so it will be good to find out now so there are no delays setting up again in the future

Edited July 23, 2013 by DoctorWho

[judgefudge]

I have a 6" setup, with the silencer set half way in the run, mostly because of the 90 bends it has to do.

 

Seems to work fine for my but i notice that i do get some noise where it first comes out of the fan, i think insulating the ducting here would help but apart from that i can't hear much after the silencer.

 

Sorry i couldn't be more descriptive as I've only had my setup going for 1 week now.

[Johnsy]

You should try a few positions and choose the quietest option Doc.

[DoctorWho]

I found that having the silence nearer to the end works best as it only affects the turbulence in the air which honestly makes very little difference to the noise being produced.  Most of the noise seems to come from the ducting itself so im going to invest in insulated ducting soon to dampen the noise even more.  I could also build a box to go around the fan but I don't really think it will be needed after everything else.

[Burning Man]

I found that having the silence nearer to the end works best as it only affects the turbulence in the air which honestly makes very little difference to the noise being produced.  Most of the noise seems to come from the ducting itself so im going to invest in insulated ducting soon to dampen the noise even more.  I could also build a box to go around the fan but I don't really think it will be needed after everything else.

I run acoustic ducting on the outside of my exhaust ducting. Makes it all massive but it is quiet.

How well do these silencers work? Ive seen a can product that seemed to have foam 'egg' cartons on the inside...

[DoctorWho]

I run acoustic ducting on the outside of my exhaust ducting. Makes it all massive but it is quiet.

How well do these silencers work? Ive seen a can product that seemed to have foam 'egg' cartons on the inside...

Knowing what I know now I would pick a speed controller first, acoustic ducting second and the silencer last in terms of stealth quality.  The silencers are pretty much a waste of money compared to the first two but if stealth is paramount I would still recommend getting one as they knock the outgoing air noise down quite noticebly but considering the first two will actually take care of the vast majority of the noise you should really only get a silencer after everything else.

[tw3nny]

Knowing what I know now I would pick a speed controller first, acoustic ducting second and the silencer last in terms of stealth quality.  The silencers are pretty much a waste of money compared to the first two but if stealth is paramount I would still recommend getting one as they knock the outgoing air noise down quite noticebly but considering the first two will actually take care of the vast majority of the noise you should really only get a silencer after everything else.

hey doctor can you recommend a speed contoller that doesnt cause that electrical frequency sound from the fan? ive had no luck with speed controllers but would like to implement one with my exhaust

Edited September 17, 2013 by tw3nny

[DoctorWho]

hey doctor can you recommend a speed contoller that doesnt cause that electrical frequency sound from the fan? ive had no luck with speed controllers but would like to implement one with my exhaust

This is the one I bought. I over paid for it at the hydro shop ($95) but I haven't noticed any noise like that.  The only bad noise my fan made was when it was turned right down to the absolute lowest I could get it and it just sounded like it was a little choppy and not enjoying life.  Turned slightly up though that noise instantly disappeared so I would have to say its a good speed controller.

 

 

In case that picture is too low quality to read its an eziPLUG fan speed controller and I use it on a 200mm Blauburg turbo inline fan.

[tw3nny]

This is the one I bought. I over paid for it at the hydro shop ($95) but I haven't noticed any noise like that.  The only bad noise my fan made was when it was turned right down to the absolute lowest I could get it and it just sounded like it was a little choppy and not enjoying life.  Turned slightly up though that noise instantly disappeared so I would have to say its a good speed controller.

 

 

In case that picture is too low quality to read its an eziPLUG fan speed controller and I use it on a 200mm Blauburg turbo inline fan.

thanks for that doc. i run a can 8 inch max fan, hope it runs fine too