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Old April 8th, 2011, 03:35 AM   #1
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Any ideas for reducing......

Has anyone got any ideas for reducing the noise that a computer fan makes. I am doing some screen grab tutorials and the fans are making too much background noise. I have a lot of equipment attached to the box, so not very practical to move the case. The computer has several fans; a large 120mm, 3 80mm, video card fan and CPU fan.

Is there some sound proof material I can wrap the case in and still let the air get around? or do you know of totally silent fans?
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Old April 8th, 2011, 04:29 AM   #2
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Re: Any ideas for reducing......

I have a stupidly noisy Macbook Pro, which makes doing this kind of thing pretty difficult. One thing I've found that has helped, is using a mic with good proximity. I use a beyerdynamic dynamic vocal mic and it does a good job when used close, of cutting out the background noise.

Apart from changing the fan, I guess you could try draping blankets over the desk to reduce the sound a little. Providing you don't block the vents of course.
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Old April 8th, 2011, 05:10 AM   #3
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Re: Any ideas for reducing......

Thanks Adrian,

I have a cheapo Sennheiser mike which does cut the noise down a bit, but introduces hiss. I purchased a Rode NT1a mike, which is superb, but far too sensitive, a poor choice for this task. The one that works the best is my Rode NTG2 with Phantom power (battery mode also creates a bit of hiss).

Will try placing the case on foam and see if that cuts down the wooden floor noise.
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Old April 8th, 2011, 06:12 AM   #4
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Re: Any ideas for reducing......

I had this problem when I was recording radio program stuff to my computer.

My first solution was to replace the three case fans with whisper fans and change a 90mm (or so) fan which was the noisiest, to a125mm fan.

The whisper fans didn't solve the problem so I went to stage two.

I made a box (from what in NZ we call Customwood - 18mm) and lined it with 50mm sound insulation. The box fits over the PC with 50mm clearance to the insulation all around. I drilled two 50mm air inlet holes in my desk so cooling air would come in from under the desk which then exited on the far side from me at the back of the computer. Given the inverse square law the sound from the exit slot was severely reduced - to effectively nothing. I sit the computer on sponge so no sound is transmitted to the desk. When in the box the PC runs about 5 degrees hotter than usual.

I have just recent found two other uses for the box.
1. Tip on end so the open bottom is vertical and it is great for putting my mic in when I want to do voice over recordings. Totally cuts out all sound from the sides and back of the mic.
2. Tip on its side so the open bottom is horizontal and it's great to put my noisy laptop in when I'm using my homemade teleprompter. Originally I teleprompted from my laptop, but because of its fan noise I put it in my sound proof box and feed from it to a silent LCD screen.

Three uses are better than one...

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Old April 8th, 2011, 01:53 PM   #5
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Re: Any ideas for reducing......

My HAF 932 computer case is also way too loud for this kind of work, even with fan speed controllers and 120mm / 220mm fans. I took two routes. First was to put sound foam in the areas I could (so long as they don't interfere with the air path). I also put up a temporary blockade (more like a reroute) in front of the air intake. It's as simple as a piece of board that re-directs the sounds away from the microphone.

The second route...and probably the more effective one in my case, was to use a gaming headset with noise-cancelling mic. A double layer of foam and super-close proximity (just below the lip or off to one side) keeps the sound very clean. You can hear the results here: YouTube - Audio Noise Fixing in Adobe Soundbooth
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Old April 8th, 2011, 03:52 PM   #6
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Re: Any ideas for reducing......

Thanks Oren,

I have tried the Headset route and have a Sennheiser set, I also invested in a PC 350 headset. I sent the 350 back as it was a bit too Boomy and picked up all the noises from lips, air etc.

At the moment I am reducing the noise via Capture Noise sample and applying the Reduce Noise filter in either SoundBooth or Audition. This works up to a point but can leave a metalic sounding voice track.

I will experiment over the weekend and post some results.
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Old April 8th, 2011, 07:46 PM   #7
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Re: Any ideas for reducing......

Lots of good suggestions so far.

Put the case on foam or carpeting, if possible, to reduce vibrational transmission.

Change fans if possible, to reduce fan noise. (IIRC, turbulance is related to the cube of linear air velocity; a fan with larger area can produce equal cooling at a lower linear velocity.)

I'd build a 4-sided box (no back or bottom -- remember the computer's already on carpeting), leaving at least 2" air space around front, sides and top of computer. Use something heavy, at least MDF. Line it with something absorbant, ideally foam/lead sheeting. The box should extend 3" or 4" behind the computer, and sit 2" or 3" away from the wall. Aim the back of the box away from the mic, toward the wall or into a corner. Then cover the wall, an area at least twice the width and height of said box, with something very absorbant, to minimize reflection of fan noise off the wall and back toward the mic.

Record ample silence before/after you record your track. First run a spectral analysis and look for steady peaks (rotational frequency of fans, for example). Eliminate just those frequencies using a notch or parametric filter. That will leave much less work for the Reduce Noise filter, which is your next step. Finally, you may be able to use a small bit of downward expansion to give you another few dB of reduction. Be sure to filter very minimally, to avoid that "robotic" sound that you've heard.

Last edited by Greg Miller; April 9th, 2011 at 03:23 PM.
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Old April 9th, 2011, 01:47 AM   #8
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Re: Any ideas for reducing......

Thank you Greg,

It looks like a box will be my best option - just off to the DIY centre right now.
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Old April 9th, 2011, 01:26 PM   #9
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Re: Any ideas for reducing......

I know you can get totally silent liquid cooling systems, but the ones I've seen are pricey. Another simple option would be to put the tower in another room or a closet, but you would need some long cables to hook up your peripherals. Most studios I've seen use a setup like that.
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Old April 9th, 2011, 09:59 PM   #10
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Re: Any ideas for reducing......

No need to fix the computer. Just move the mic closer.
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Old April 9th, 2011, 10:09 PM   #11
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Re: Any ideas for reducing......

Good point, Christian. I was also thinking about another option, which would be to get the mic as far from the computer as possible. A 50' XLR cable isn't that pricey. Instead of isolating the computer, maybe isolate yourself in the nearest closet, perhaps. You can cover a lot of ground with 50 feet of hose.
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Old April 9th, 2011, 11:58 PM   #12
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Re: Any ideas for reducing......

Before you spend more than $200us on any technical or mechanical solution, note that as a 25 year plus VoiceOver pro who's done literally HUNDREDS of paid VO gigs - I've sold off all my expensive processing gear and now do all my work with a single mic (happens to be a Neuman, but that's largely irrelevant since it's just the latest of many, many mics, from expensive to dirt cheap I've used over the years.) and a $250 Zoom H4n.

The point of all this is that the Zoom is totally silent.

So another approach is just buy a similar silent recorder - and shut anything noisy (including the computer) off. Bingo, end of problem.
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Old April 10th, 2011, 04:32 AM   #13
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Re: Any ideas for reducing......

Good suggestion Bill, I do have a Sony PCM D50 which is totally silent and will record uncompressed audio. The only problem with your suggestion is that I need the computer ON in order to produce a screen shot tutorial.

Thanks also to Andy, but taking a monitor, keyboard, Wacom tablet, mouse, scanner etc into my closet doesn't work for me.

At the moment I am using the Rode NTG2 fairly close to my mouth (Dead Cat fitted) and it cuts down on the ambient noise quite a bit.

I guess that as this DVD is designed to be played on a computer, then most people will have their own fan noises in the background, so hopefully the now small amount of fan noise from my end will be lost in the viewers environment.

Wishful thinking perhaps :-}
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Old April 10th, 2011, 06:33 AM   #14
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Re: Any ideas for reducing......

I've been in the same situation. Here are a couple of ideas I've had without buying expensive panels, which may be a good answer if you plan on doing this a lot:

1. El-Cheapo and in a hurry: Use sofa cushions around the computer box on top, back (leave 4" airgap) and side closest to user, extending beyond front and back of computer. I then place pillows or cushions around back and sides of microphone. Don't block off the cooling fan intake or exhausts!

2. El-Cheapo if you have time: Script the segments with time durations of each segment on index cards. Take Zoom mic and stopwatch into a clothes closet and record the VO there. You'll be amazed how good audio sounds in a clothing closet! Write down the Zoom track ID for takes you think are good for each index card and insert into the piece when you get back to the computer.

3. Buy a long XLR cable, a long display cable (could be a 2nd monitor), and a wireless mouse and keyboard (or long cables). Move yourself behind a barrier and do the VO.

4. I'm currently working with a program called "Air Display" on my iPad that can act as a wireless 2nd monitor for my PC. In theory you can control your PC with it, but to date it doesn't stream video very well over my wireless network and the PC control is spotty. Still trying.

Hope one of these is helpful
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Old April 10th, 2011, 09:02 AM   #15
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Re: Any ideas for reducing......

Solution found.

I wave just rigged up my external sound card (Presonus Firestudio Mobile) up to my laptop and am now recording directly to an external hard drive. I can edit the tutorials and captured sound track on the main computer at a later stage.

This was not possible before as my laptop has a poor internal soundcard and generally didn't capture a strong enough audio level from my mikes. I therefore never used it to make any recordings. The setup works just fine now, with very little, if any, fan noise.

Thank you for all your suggestions
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