Walker Posted September 20, 2012 Share Posted September 20, 2012 Hello, Hoping someone with a bit of soundproofing experience may pick this up and be able to offer some advice. In the corner of my office, we have an open 2 tier shelf with 8 PC servers on it. They are on 24/7 and the noise of the fans needs to be subdued somehow. I've got two office screens made of lightweight inch thick fibreboard. This helps a bit, but not much, so I was considering attaching acoustic foam to the back of the screens. I dont need to totally remove the fan noise (we'd need a soundproof cabinet for that), I just want to minimise it. Would the acoustic foam on the back of the screens help at all? Thanks very much, Chris Quote Link to comment Share on other sites More sharing options...
51m0n Posted September 20, 2012 Share Posted September 20, 2012 (edited) Not a lot. Server fan noise its really irritating, and when you get enough of them you tend to get the sound of all the different fans 'beating' against each oither creating a lot of eneregy at far lower frequencies than you get from any one or two fans IME. To defeat lower frequencies you want mass, and plenty of it. Get some high density membrane (as used for acoustic dampening in building). Glue it to both sides of your screens, cover that in half inch mdf (bolt it through or screw it in). Now the screen is so heavy you may need to strengthen its legs I'm afraid. On the side facing the server box add 4 inch thick rockwool rw30 or rw45 covered with hessian or som eother acoustically transparent materal (ie hat you can blow through). You wont hear the fans with those in the way (you have effectively just built a couple of gobos). If you dont think you have any meaningful low energy output going on then just use the rockwool and material to create a couple of lighterweight higher frequency broadband absorpers. Edited September 20, 2012 by 51m0n Quote Link to comment Share on other sites More sharing options...
Walker Posted September 20, 2012 Author Share Posted September 20, 2012 Thats why I love this place! Thank you so much for the advice. I've attached a reading of what I'm getting withing 6" of the servers, so looking at that, would your full monty be the way to go rather than just the rockwool option? Quote Link to comment Share on other sites More sharing options...
charic Posted September 20, 2012 Share Posted September 20, 2012 I have nowhere near the same experience as 5imon on this but sometimes adding two layers is more beneficial than adding one massive layer. The airspace in between the two areas causes much more energy to be absorbed Quote Link to comment Share on other sites More sharing options...
BigRedX Posted September 20, 2012 Share Posted September 20, 2012 Don't forget that you still need to dissipate all the heat the servers are generating. Servers tend to have noisy fans because it is assumed that they will be hidden away in their own room where the sound isn't an issue. I'd look at replacing all the fans with quieter models first. You might not need so much sound proofing then. Quote Link to comment Share on other sites More sharing options...
51m0n Posted September 20, 2012 Share Posted September 20, 2012 [quote name='Walker' timestamp='1348133004' post='1809660'] Thats why I love this place! Thank you so much for the advice. I've attached a reading of what I'm getting withing 6" of the servers, so looking at that, would your full monty be the way to go rather than just the rockwool option? [/quote] Well you have a lot of very very low frequency in there - which is unlikely to be the fans (traffic noise, air con maybe?), but nothing is much louder than 65dB so we arent talking huge amounts of energy here. You definitely want to try to block out anything above 125Hz if you can, you have the kind of noise I was expecting in the mid range, and a very nasty spike at 16KHz which is possibly whats driving you mad as you probably cant perceive it as more than something very irritating about being near those fans. The 16Khz would be blocked by your existing partition without any trouble. So dont worry about that. I would look at trying just the mdf and rockwool - the bitumen acoustic matting is not pleasant to work with (its unbleievably heavy - duh!) and is expensive, the mass of the mdf may be enough to control this with the absorption layer of a good 4" thick of rw45 over it. If the very low frequency stuff is annoying you after that (unlikely to be honest, its not loud enough) then adding bitumen may help, but you are really heading into the realms of full floor to ceiling partition walls then since low frequency suff is omni directional and will be going everywhere. [quote name='charic' timestamp='1348134059' post='1809683'] I have nowhere near the same experience as 5imon on this but sometimes adding two layers is more beneficial than adding one massive layer. The airspace in between the two areas causes much more energy to be absorbed [/quote] Absolutely right Charic me old mucker! If you are looking to build a partition wall type thing from scratch than an air space is definitely the way to go. The BBC site has some excellent white papers and R&D on this type of thing - search for the 1995 r&d paper #06 "Lightweight partitions having improved low frequency sound insulations" for a good lesson in making super efficient 'lightweight' (err not so much) partition walls. Not done so much in gobos (IME), since the airspace boundaries need total separation from each other or you are just adding transmicssion points through the gobo. Which sort of defeats the object really. You just want something heavy as hell, and floor to ceiling (or near as) from a gobo. Quote Link to comment Share on other sites More sharing options...
Walker Posted September 21, 2012 Author Share Posted September 21, 2012 Thank you for your help gents. I'm going to take another reading very early in the morning just to make sure (no background noise, etc.) and then build something appropriate based on your advice. Thanks again, amazing info. Chris Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted September 21, 2012 Share Posted September 21, 2012 As a temporary measure, you could do worse than a couple of sheets of [url="http://www.wickes.co.uk/invt/190544/?source=123_75"]http://www.wickes.co.uk/invt/190544/?source=123_75[/url] I've used this stuff to partially-soundproof the thin steel garage doors of my studio. Very lightweight and easy to move around into different positions, very easily trimmed to shape/size. Not a long-term solution but a good way to experiment with noise reduction. Quote Link to comment Share on other sites More sharing options...
51m0n Posted September 21, 2012 Share Posted September 21, 2012 That celotex insulation wont offer any meaningful isolation below about 1KHz Its lightweight, so it doesnt prevent lower frequencies from passing through it. Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted September 21, 2012 Share Posted September 21, 2012 Agreed, but for fan noise and that "white noise roar" you get from servers, it will certainly take the edge off it. Quote Link to comment Share on other sites More sharing options...
51m0n Posted September 21, 2012 Share Posted September 21, 2012 Not so sure about thT Jack, take another look at the frequency plot up above, an awful lot of energy between 125Hz and 1Khz, which that foam wont really touch. Yes it wont be so bright, yes the 16KHz will be dealt with but there will still be all the mid and lo frequency hum and air noise, the fan whirr will be lessened slightly. The gobos I described are 4" thick plus the mdf and existing structure (maybe 6" thick in total), and even then they will only deal with the direct path from the source, but they will at least deal with that.... Quote Link to comment Share on other sites More sharing options...
charic Posted September 21, 2012 Share Posted September 21, 2012 Thought of something else, depending on the size of the rack it is possible the rack itself is vibrating and in turn turning the floor into a sounding board. Worth checking the metal of the rack for vibrations I honestly think your first port of call is changing the fans if possible though Quote Link to comment Share on other sites More sharing options...
Walker Posted September 21, 2012 Author Share Posted September 21, 2012 Do they make an 8' x 2' auralex gramma pad?! Quote Link to comment Share on other sites More sharing options...
charic Posted September 21, 2012 Share Posted September 21, 2012 Probably not but you can It's just foam and mdf IIRC Quote Link to comment Share on other sites More sharing options...
solo4652 Posted September 21, 2012 Share Posted September 21, 2012 [quote name='charic' timestamp='1348221930' post='1810990'] Probably not but you can It's just foam and mdf IIRC [/quote] Anti-vibration mats: [url="http://www.keepitquiet.co.uk/vibration_pad.html"]http://www.keepitquiet.co.uk/vibration_pad.html[/url] [url="http://www.soundsolutionconsultants.co.uk/acoustic-product/sound-mat.aspx"]http://www.soundsolutionconsultants.co.uk/acoustic-product/sound-mat.aspx[/url] [url="http://www.polymax.co.uk/rubber-anti-vibration-mount/rubber-pad/rubber-anti-vibration-mat"]http://www.polymax.co.uk/rubber-anti-vibration-mount/rubber-pad/rubber-anti-vibration-mat[/url] [url="http://www.studiospares.com/sound-insulation/acoustistop-rubber-floor-tile/invt/465130/"]http://www.studiospares.com/sound-insulation/acoustistop-rubber-floor-tile/invt/465130/[/url] Quote Link to comment Share on other sites More sharing options...
51m0n Posted September 21, 2012 Share Posted September 21, 2012 Any number of drum riser type/size devices to minimise sound transfer are available - cheapest option, two pieces of ply, some 1/2" baton and a load of tennis balls Quote Link to comment Share on other sites More sharing options...
BILL POSTERS Posted September 21, 2012 Share Posted September 21, 2012 Only skipped through this thread quickly, we get complaints about CCTV DVRs being noisy - cos they are, usually, and two or more together sounds like a vacuum cleaner if you put them in a cupboard. sometimes. Puttint them on a solid base, ie a paving slab or a piece of heafty kitchen worktop helps, but obviously if theyre rack mounted you cant, especially if theres a door and a back on a timplate rack cabinet it makes things worse. Just wondered if anybody on here has actually tried soundproof paint. Sounds like an april fools joke really doesnt it ? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.