Extracting into same room

[Eldo]

Hello uk420 

 

I'm extracting straight out the top of my drobe with only 1 passive intake to the side

 

Thinking of extracting straight into a box packed with those cheap dehumidifier things to try and quieten noise and stop moisture build up outside room....could I make this work?......would a couple of meters of ducting running round top of drobe before the box help with noise reduction??

 

Think im going to have to add more passive intakes or an inlet fan but for stealth/noise reasons I'm reluctant to do so.....could some DIY co2 bottles along with a cheap co2 meter be the answer? My reasoning is plants won't require too much for 1st few weeks and if meter reading shows as too low then I can add the intake fan before it becomes a problem

 

I know this set up leaves a lot to be desired but I'm hoping can somehow make it work

 

[Should Know Betterer]

Hi @Eldo, good to see you're getting started, you really want to keep the ducting length down to a minimum,  there's charts online that show how much each bend and each meter impacts on the efficiency of the extraction system, and tbh I don't think extra length on ducting will help stop noise, look into an ec fan if you haven't got one, site sponsors ledgrowlights just sold me my one cheaper than elsewhere and it's much quieter than my old Black Orchid. I have long ducting wrapped around my pots coming from an oil rad in a box outside tent, but that doesn't do any extraction and it keeps my root zone at a nice temp, others will tell you too don't mess with your extraction it's important for keeping it no smell, good luck getting it all up and running man, oh and autos I usually go no more than 1cm deep straight in final pots, some root out first some don't, I don't. 

[Eldo]

Hi @Should Know Betterer thanks mate, they some lovely looking plants there  

 

I have the same fan as you, it was your post yesterday that made me realise I will need to run it at around level 4/5 as opposed to the 2/3 I had hoped for. Have added a long open cardboard box on top of drobe that fan blows directly into which seems to have reduced noise without affecting airflow too much

 

Been running empty drobe last 24 hrs average ambient temp 24 degrees although root zone went to 16.8 at lights off overnight. (0 degrees outside)

 

Plan is run lights 24 hours for 1st 2 - 4 weeks until outside temps improve

 

I beleive 21 is the magic number Im looking for at root zone?

[Moby]

Hi @Eldo, for cost effective noise control think about what noise is; waves of vibration in the air. Low frequency sounds are big long waves, high frequencies are rapid shallow waves.

 

The waves bounce off things and find their way around stuff. So to reduce noise you either make less in the first place, absorb it and/stop it bouncing. 

 

Low frequencies need absorbing with physical mass, high frequencies will require less mass to absorb them, but they'll fit their way through the tiniest cracks. 

 

A hydro setup will have a few things that contribute together to the overall sound. Air stones are supprisingly loud, bigger circulation fans will make a lower droning sound, smaller fast ones will be more high pitched. 

 

Most of the noise from an extraction fan is fairly a mixture of frequency's. People advise and EC fan because you can speed control them without the electric motor humming. So you can slow them and make less noise... But slow means less air (and C02) circulating through the grow space as well...  You can actually slow AC fans as well, don't get a £15speed controller or dimmer switch, the motors will make a horrible noise.. instead you need a 240v variable transformer, somtimes you see them second hand, or you can get one new for £50 from eBay.... But you might not allways want slow fans... So to reduce the noise from a full speed extraction fan without spending loads you can do the following; 

 

Use acoustic ducting;  5m legnths of phonic trap are about £40... I think... This stuff is brilliant, it's basically a silencer. Alot of fan noise is sent down the ducting from the noise of the actual fan blades moving through the air. The ducting has absorbant walls which trap the sound and absorb the vibrations. At the cost of a tiny negligible amount of air flow, route the ducting a round a gentle curve so the sound waves (that travel in a straight line) have to hit a wall (and be absorbed inorder to make it out of the ducting. Use a length of this on either side of the fan so you reduce noise escaping from the filter as well. 

 

Box your fan, house your fan in a heavy box... Even just putting the fan on a very heavy paving slab (lots of mass and hard to transmit sounds) then sticking a cardboard box over it and duct taping the box to the slab, sealing any holes or joint between cardboard and ducting with tape and making sure the fan doesn't contact the box... Even this will make a massive difference.. the air tightness will block CK high frequencies, the non contact with the box will reduce transmitted sound. The next level version of this is to make wooden boxes for your fans. Use the thickest MDF you can, 18+mm, make an airtight box that holds you fan in the middle suspended on bits of foam. Cut holes for the ducting and tape the crap out of any gaps..

 

 

I have cheap RK AC fans in mdf boxes with a transformer/speed controller and acoustic ducting. At full speed they're very quiet, barely audible..at low speed you can really hear them at all, you just get a silent breeze coming from the outlet. 

 

Other things to think about are keeping the noise in you enclosure, hand filter boxes inside and any noise from the box has to also get through the enclosure to the outside. You can hang old carpet behind your reflective sheeting and it will stop sound reflecting and reduce it being transferred through the walls of the space. block up cracks in doors with draft sealing strips and just let air in in a controlled way, ideally through acoustic ducting..  

 

My current grow is fairly quiet, but not amazing.  in the past I built an 8x4ft 1200watt grow you could stand immediately next to and just not hear at all, even with all the extraction/circulation fans, air stones and dehumidifier running at full speed. If you get nerdy about it and like building stuff you don't need to spend a lot of money. 

[Moby]

Hi @Eldo, for cost effective noise control think about what noise is; waves of vibration in the air. Low frequency sounds are big long waves, high frequencies are rapid shallow waves.

 

The waves bounce off things and find their way around stuff. So to reduce noise you either make less in the first place, absorb it and/stop it bouncing. 

 

Low frequencies need absorbing with physical mass, high frequencies will require less mass to absorb them, but they'll fit their way through the tiniest cracks. 

 

A hydro setup will have a few things that contribute together to the overall sound. Air stones are supprisingly loud, bigger circulation fans will make a lower droning sound, smaller fast ones will be more high pitched. 

 

Most of the noise from an extraction fan is fairly a mixture of frequency's. People advise and EC fan because you can speed control them without the electric motor humming. So you can slow them and make less noise... But slow means less air (and C02) circulating through the grow space as well...  You can actually slow AC fans as well, don't get a £15speed controller or dimmer switch, the motors will make a horrible noise.. instead you need a 240v variable transformer, somtimes you see them second hand, or you can get one new for £50 from eBay.... But you might not allways want slow fans... So to reduce the noise from a full speed extraction fan without spending loads you can do the following; 

 

Use acoustic ducting;  5m legnths of phonic trap are about £40... I think... This stuff is brilliant, it's basically a silencer. Alot of fan noise is sent down the ducting from the noise of the actual fan blades moving through the air. The ducting has absorbant walls which trap the sound and absorb the vibrations. At the cost of a tiny negligible amount of air flow, route the ducting a round a gentle curve so the sound waves (that travel in a straight line) have to hit a wall (and be absorbed inorder to make it out of the ducting. Use a length of this on either side of the fan so you reduce noise escaping from the filter as well. 

 

Box your fan, house your fan in a heavy box... Even just putting the fan on a very heavy paving slab (lots of mass and hard to transmit sounds) then sticking a cardboard box over it and duct taping the box to the slab, sealing any holes or joint between cardboard and ducting with tape and making sure the fan doesn't contact the box... Even this will make a massive difference.. the air tightness will block CK high frequencies, the non contact with the box will reduce transmitted sound. The next level version of this is to make wooden boxes for your fans. Use the thickest MDF you can, 18+mm, make an airtight box that holds you fan in the middle suspended on bits of foam. Cut holes for the ducting and tape the crap out of any gaps..

 

 

I have cheap RK AC fans in mdf boxes with a transformer/speed controller and acoustic ducting. At full speed they're very quiet, barely audible..at low speed you can really hear them at all, you just get a silent breeze coming from the outlet. 

 

Other things to think about are keeping the noise in you enclosure, hand filter boxes inside and any noise from the box has to also get through the enclosure to the outside. You can hang old carpet behind your reflective sheeting and it will stop sound reflecting and reduce it being transferred through the walls of the space. block up cracks in doors with draft sealing strips and just let air in in a controlled way, ideally through acoustic ducting..  

 

My current grow is fairly quiet, but not amazing.  in the past I built an 8x4ft 1200watt grow you could stand immediately next to and just not hear at all, even with all the extraction/circulation fans, air stones and dehumidifier running at full speed. If you get nerdy about it and like building stuff you don't need to spend a lot of money.