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richardhenry's avatar

Removing the noise of a computer fan from an audio recording?

Asked by richardhenry (12651points) May 10th, 2008

We had to record the latest episode of our podcast on my MacBook Pro, on my lap. Unfortunately without realising, my leg was blocking the vent and the fan kicked in to compensate.

Although we didn’t notice the sound of the fan while we were recording, we got to the end of the hour to discover that the microphone picked up the fans amazingly well and it sounds like we’re on a plane.

Any suggestions as to how I can remove the fan audio? Thanks!

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9 Answers

richardhenry's avatar

I’ve tried killing it on the EQ but it makes our voices sound really bizarre.

paulc's avatar

Audacity has a noise filter that I’ve used to drown out traffic noise on an audio track in the past – it worked pretty well. Takes a bit of playing with but you should be able to improve it at least a bit. I don’t remember if the exact filter/tool is called “noise filter” but if you play around with what’s available in the menus you should find something.

Spargett's avatar

Apple’s Soundtrack has the ability to sample any “white noise” and then remove it from the remainder of the track.

Pretty amazing. Google will lead you in the right direction to the tutorial. I think its even on Apple’s site.

sndfreQ's avatar

Yes…Spargett’s on the money on Soundtgrack; if you are on Mac OS, that would be a good direction for you; I do believe GarageBand has some EQ presets under Vocals, for podcasts, though they won’t eliminate that kind of ‘broadband’ noise. What they will do is ‘sweeten’ the tone of the vocals (male or female), and place a nice bump in the tenor range of the voice, which may downplay the treble aspects of the fan. You can also try a parametric EQ, and using the notch setting, duck out a narrow band in the 1–2KHz range; I believe the primary fan tone is in that range (I can’t make my fan turn on at the moment but it’s an educated guess).

If spending money is no problem, you could look into a $129.00 Audio Units plug-in: Bias’ SoundSoap 2.

richardhenry's avatar

Thanks all, I’ll look into a few options.

digitaljesus's avatar

if you any familiarity with a program called ProTools, that would be what to use. That’s what professional audio engineers use for movies/music recording. There is a plugin called “Xnoise” that can do exactly what you need. Works like a charm and makes it almost sound perfect. If the other solutions above don’t work, you might want to look into it. Hope this helps!

sndfreQ's avatar

digitaljesus is right, however, the fine print here is whether or not you already have ProTools. FYI, you need a full ProTools HD hardware and software rig to run the Waves plug-in XNoise (ProTools HD, which with the entry level HD system runs about $14,000.00!); then, the cost of admission for XNoise the plug-in is $2,400, as it is only offered bundled in a Waves bundle (the Broadcast and Production bundle is the entry-level bundle that includes XNoise).

Alternately, running Digi TDM hardware (the HD card, plus a Digidesign audio interface, ~$9K), along with Apple’s Logic which will support the use of TDM plug-ins, then you would be able to use XNoise with Apple Logic Pro/Studio (still a multi-thousand dollar proposition), plus buying that B&P bundle at $2400.00.

An alternative to that kind of expenditure is to use Waves’ next ‘step down’ from XNoise, called ZNoise, and runs about $800 for the Audio Units version (AU is the ‘native’ Mac OS protocol for plugs that run natively in Mac OS X), so you would be able to use this without investing in additional digi hardware / software. ZNoise will run in any MacOS native audio app that supports Audio Units (e.g. GarageBand, Logic, Soundtrack, and other non-apple digital audio software).

Digidesign (the company that makes ProTools) has a quasi-native plug-in that is made for their ProTools LE edition, called DINR (Digidesign Intelligent Noise Reduction), which in terms of quality, is probably in line with my recommendation above for SoundSoap2. The link for DINR is here. Keep in mind that SoundSoap2 runs natively in any Audio Units-capable audio app, not just ProTools LE.

The interesting thing to note is that Digidesign now rents their plug-ins; Waves did too at one point, but I no longer see that option in their online store. I noticed that DINR only costs $12 to rent for two days; this might be a good option if you own PT LE already. Hope you find this info helpful.

richardhenry's avatar

Thanks sndfreQ! Very useful to consider for the future. We’re quite new, and although we’ve been sponsored, we really don’t have much funding. We’ve decided to not release this episode (it does sound really bad) and I tried the noise removal in both Soundtrack and Audacity and we ended up sounding like we were broadcasting from inside a bucket.

We just really need to get hold of a good podcasting microphone, and if we do need to carry on recording on my MBP then we’ll have to do it on a table.

goldmine178's avatar

use a soundproof…..... or move you mic

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