February 8, 2015 at 2:40PM

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What's the best way to cut down background noise in editing?

I am filming several cooking shows that take place in a grocery store's kitchen, and just wrapped up the 1st day of shooting today, and unfortunately there is some humming from various store appliances or whatnot. I used a lavalier mic with my Zoom Q3HD, but the audio turned out extremely poor, so I am forced to use the in-camera audio of my Canons. Are there any good methods for toning the unwanted sounds down in post?

17 Comments

Number 1 : Un-plug fridges that are in the same room and turn off fans when you are shooting. You might need to have a person on set whose job is to turn these items on and off between takes.

Number 2 : Use lav mics under people's clothes ( this requires lavs with an upper range peak that will compensate for the muffled sound of recording through clothes ), which helps to mask out some of the room noise.

Number 3 : Use a narrow pick-up shotgun mic like the Sanken CS-3e which won't pick up much of the room noise, but you have to have it properly aimed at the person speaking. It's a very directional mic. ( you can rent this mic, as it's not cheap to buy )

Number 4 : Hang sound blankets ( usually people use padded moving blankets ) to absorb stray sound and block noise from the set.

Number 5 : Always record ambient-noise sound so you can use it to build a noise-reduction filters in post which will help to reduce the amount of noise in your recordings.
( I use the Sony Sound Forge noise-reduction filter, but there is better noise reduction software on the market like iZotope RX4 software )

Number 6 : Do what the TV shows do, and use background music to mask the noise.

February 8, 2015 at 4:55PM

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Guy McLoughlin
Video Producer
30861

Thanks for the reply Guy, I appreciate the info! This is my first attempt at something like this, as I normally film live performances, so I may have bitten off more than I can chew.

Ian Pfister

February 9, 2015 at 7:27AM

A high pass filter of like 150 to 300hz, or Wind cut filter in the camera settings could help very much too to reduce noise and mudness in the audio.

Natan Duarte

February 9, 2015 at 6:12PM

Your number 1 is brilliant. When you read it, it's one of those doh! moments. How obvious, once someone has told you.

Julian Richards

May 12, 2015 at 9:20AM

I've seen iZotope RX in action and it's impressive. with some reading can make miracles if you can't retake the audio.

https://www.izotope.com/en/products/audio-repair/rx

February 9, 2015 at 6:12PM

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It may be easier to fix the issues with the audio recorded with the Zoom. Care to elaborate on the issues with that audio?

Camera audio is going to have more issues than just background noise. As mentioned above iZotope RX4 Advanced is incredible. I also highly recommend Waves C4. It's labeled as a multi band compressor, but has a noise reduction preset and works similarly to Cedar DNS which is the post production industry standard tool for noise reduction.

February 9, 2015 at 6:29PM

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I highly recommend iZotope RX 4. It`s such impressive how it saved sound recordings I had to edit for a soccer game. The essentials are easy to learn just by tryring out the sliders and using presets but I recommend digging deeper into the software because you will be able to save a lot of sound files if you know this software/plug.

February 9, 2015 at 7:00PM, Edited February 9, 7:00PM

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Tobias Vogel
Producer / VFX Artist
106

Great tool/technique for eliminating certain background noises and sounds is spectral cleanup. It does require manual work, but you can "repair" your audio in a visual intuitive way. In my opinion this is one of the best (but certainly not the fastest) way to get clean audio.

To get an idea what I'm talking about take a look at that:
http://tv.adobe.com/watch/learn-audition-cc/using-the-spectral-frequency...

Using that in conjunction with gates, compressors, EQs and noise reduction filters this can really do the magic for otherwise unusable audio recordings.

But having clean audio in the first place is always the best solution. ;)

February 9, 2015 at 7:22PM

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JanR88
3D, VFX, Video & Motion Graphics Generalist
86

Wow thanks a lot everyone. It seems the consensus is to go with iZotope RX 4 to clean up audio. I don't have the budget for that at the moment, but I did order a cheap Sound Forge program, which seems to accompany the Sony Vegas Pro 12 that I use.
It was my 1st time trying to use an external mic on my Zoom, as I don't need it filming live bands. I bought a cheap Audio-Technica Lavalier mic (it was a last minute gig) from Microcenter. The issue with my Zoom audio is the jack receiver just doesn't accept the mic jack (or any 3.5) well. Like you have to pull it out just at the right spot for the signal/levels to respond correctly, and with my subject moving around... it just didn't work as I intended. It's not savable even with the top notch programs out there. I'm going to see if I can clean up the buzz and hums of appliances from my camera audio with sound forge at all.
Is it worth it for me to buy a lower priced shotgun mic ($100-200)? As there is little to no budget for me to rent as much as I'm going to need it.

February 9, 2015 at 7:39PM

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Ian Pfister
Owner/DP/Editor
192

re: mics. I use a Rode NTG2 shotgun mic ($200ish) recording (XLR balanced) into a Zoom H4N. Great little budget setup especially for on location work. Problem with any digital recorder with no XLR input is that the signals going in are generally unbalanced, that's why it's easier to pick up radio & electromagnetic signals nearby. I also use a Rode Smartlav with an iPhone/iPad, handy but quite hissy (the smartlav+ is better), so hard to get that crisp, present sound. I use the 'de-hiss' processing on the rode rec app and add some top-end eq/compression in post and mix with shotgun mic audio for more more body/ambience if needed.

David Brant

February 10, 2015 at 1:32AM

The best low-cost shotgun mic for indoors recording is the Audio Technica AT875R mic which sells for about $170. The main feature of this mic is that it has very good off-axis sound rejection so you won't pick up much reflected sound when shooting indoors. ( the RODE NTG-2 has poor off-axis sound rejection and is not a good mic to use indoors in small rooms or highly sound-reflective spaces )

NOTE: The AT875R mic is a bit "thin" in the lower audio range, so you will want to use a bit of EQ to fix this in post.

Guy McLoughlin

February 10, 2015 at 8:46AM

You will get the best results from the Sony Sound Forge noise-reduction filter if you remove noise in multiple passes. Use "mode 3" and no more than 9 dB reduction at a time. You will know when you've gone too far when the dialog starts to sound distorted and robotic, so use the un-do feature to go back to a previous version. ( just don't save until you are happy with the audio quality or you will lose your un-do's )

Guy McLoughlin

February 10, 2015 at 8:52AM

In editing, after the fact when you already have your audio, you can try using Audacity which is free. http://youtu.be/ZqeG2ZiN_6A

February 9, 2015 at 11:31PM

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The latest version of Adobe Audition CC has a great restoration tools and spectral noise removal system for getting rid of mic pops, tone hums, knocks & other background noises - I find it's less fiddly than Izotope RX4's spectral noise remover - but its has to be said RX4's noise reduction system is fantastic.

February 10, 2015 at 1:15AM

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David Brant
CEO
98

Here's a clip of what I'm talking about. This is with no altering of the audio yet at all... http://youtu.be/YR3gwManPC4

On a side note, it really doesn't matter anymore since I had to let the job go today to somebody else due to personal family issues atm, but the client is having me give them the footage I shot to incorporate it in if they choose.

February 10, 2015 at 8:54PM

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Ian Pfister
Owner/DP/Editor
192

I took a quick stab at cleaning up your audio. It's not great, but it's a fair bit less noisy. If this was a paid shoot, I would reshoot for free and get the audio right this time.

20 MB ZIP file containing a 48 kHz 16-bit WAV audio recording
https://drive.google.com/file/d/0Byy1CMO9Zfmra01ZR0FIQ1pHbVU/view?usp=sh...

February 11, 2015 at 2:48PM

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Guy McLoughlin
Video Producer
30861

(Un) noticed electrical hum, could be ruining your audio recording. You could try from your Audio Software a DeHummer effect to remove 60 Hz and Harmonics (or 50Hz depending on local electricity system used).

February 18, 2015 at 9:34AM

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Tobias and JanR88 hit it. These are more reliable approaches than most de-hum or noise reduction scans, because they don't eliminate any of the useful sound. Also, try to do a "clean" handle for every scene; record 5-30 seconds of your set or location, with no sound from cast or crew. Or you can record it as a separate clip, but remember to label it for the scene.

July 3, 2017 at 12:37PM

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