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  • Tue, May 17 2011 6:38 PM

    • dvasquez
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    • Joined on Mon, Oct 19 2009
    • Posts 3
    • Points 145
    • Avid Employee

    Noise Reduction in Avid Media Composer 5.5

    All production audio has some unwanted sonic elements.  In some cases, these elements may be acceptable and actually add character to a particular scene.  More likely, the picture or sound editor will be tasked with minimizing or completely removing these unwanted elements.  

     

    Sound editors have a huge arsenal of tools at their disposal—from dedicated hardware units from CEDAR and other manufacturers, to the latest plug-in based technologies from CEDAR, Izotope, McDSP, Sonic Solutions, Sonnox, Waves and more.

     

    But, what about the picture editor?   It’s true that many of the plug-ins mentioned above can be used in today’s professional editing applications.  But, not many picture editors can afford such a luxury with so many other priorities to consider.  Fortunately, using the basic tools included in most editing applications, the picture editor can achieve a result that significantly reduces these unwanted sonic intruders.

     

    Audio EQ Tool

     

    The first method for reducing unwanted noise is to use the standard EQ tools that are included in every editing application.  In Media Composer, this tool is known as the Audio Equalization Tool (or Audio EQ Tool for short).   The Audio EQ Tool performs real-time, segment-based equalization on individual clips.  It has a simple interface with low, mid, and high frequency band controls that can be used to adjust the sonic characteristics of an audio clip.  

     


     

    If all this talk about frequency band controls has your eyes glazed over, you’re not alone.  Even the most beautiful plug-in interface cannot help the fact the audio equalization can seem extremely technical and counterintuitive.  (See the EQIII interface design below for a good example.) Fortunately, the real strength of the Audio EQ Tools lies in its preset library.   Like many EQ plug-ins optimized for audio post-production tasks, you’ll find a nice assortment of settings to aid in noise reduction, as well as several settings offering some creative processing options.  Clicking on the Fast Menu in the Audio EQ Tool interface will bring up the preset library.

     


     

    As you can see, there are several useful settings available, from telephone “futzes” to basic vocal and music enhancement presets.  But, let’s get back to the task at hand.  The two most useful settings for noise-reduction are definitely “NTSC Hum Buster” and “PAL Hum Buster.”  These settings are designed to eliminate 60-cycle and 50-cycle hum (respectively), which is probably the most common narrow-band noise issue encountered in audio post-production.  And these settings don’t just go after the obvious fundamental frequencies; they offer a series of additional filters that eliminate the naturally occurring overtones that can stretch for several octaves above the fundamental.  This type of setting can take a lot of work to create from scratch!

     


     

     

     

     

    Seek and Destroy

     

    The Audio EQ Tool is great for recalling presets, but its interface design is focused on simplicity rather than power.  If a preset isn’t going to do the job, it’s wise to move up to a more full-featured EQ plug-in such as Avid’s EQIII series.  This plug-in is available in Media Composer in both clip-based form (known as AudioSuite), and real-time form (known as Real-Time AudioSuite or RTAS).  In addition, there are 1-band, 4-band, and 7-band flavors of EQIII.

     


     

    The 7-band EQIII has a beautiful interface that presents information in two different formats—the traditional knob-based interface with controls for frequency, gain and Q settings, and a large graph in the upper right corner with color-coded points that visually indicate the position of each EQ band.

     

    For our purposes, the 1-band EQIII should suffice.  Let’s imagine that we’ve got a nasty squeal in our production sound from a camera or other electronic device that was present in the original production location.  The best way to tackle this type of annoyance is using the “Seek and Destroy” method of noise reduction.  This is easy to accomplish with the 1-band EQIII.

     


     

    The basic technique is simple.  First, set a high Q setting so that the frequency band becomes very narrow.  In EQIII this would be a setting of 8-10 but will vary with other plug-ins.  Then increase the GAIN by a large amount, such as +12 dB.  This will make any sonic element that falls within the band quite loud and easy to distinguish from the rest of the clip.  Finally, sweep the frequency of the band up and down using the FREQ control.  You should be able to home in on the offending squeal.  Once you’ve located the sound, there are two steps additional steps to follow.  First, invert the GAIN setting so that you’ve got a large amount of reduction, such as – 12dB.  Then, gradually reduce the Q setting until the entire noise disappears.  The trick is to widen the band just enough to remove the squeal without impacting the rest of the clip any more than necessary.

    Broadband Noise Reduction

     

    Some times a noise is masking such a huge frequency range that it cannot be eliminated using a standard EQ.  This is generally referred to as “broadband noise.”   Broadband noise includes natural sounds such as rain or running water, and artificial sounds such as room tone, air-conditioner rumble, and vehicle interiors.

     

    There are many excellent plug-ins on the market that do a good job of reducing some types of broadband noise.  However, it should be noted that broadband noise can generally only be reduced and not eliminated. The more stable the broadband noise the better it can be reduced.  Some sounds, like wind or ocean waves, are virtually impossible to reduce.  So it’s important to set realistic expectations with the producer or director before tackling broadband noise issues.  It’s always good to remind them that this is why ADR was invented!

     

    Let’s take a look at general broadband noise reduction techniques using the Avid Broadband Noise Reduction (or BNR) plug-in.   This plug-in uses a technique that is probably the most common among BNR plug-ins.  First, it analyzes a small portion of audio to create a “noise signature.”  This audio must be selected from a portion of the clip where the noise exists but there is no dialog. 

     


     

    Next, the plug-in uses a complex series of EQ bands to create a “noise contour line” which will be used to reduce the broadband noise. 

     


     

    Simultaneously, the plug-in is creating a model of what the non-noise audio signal looks like.  Then, BNR attempts to pull the noise contour line and non-noise model away from each other to reduce the broadband noise while attempting to minimize the impact on surrounding audio.  BNR includes controls for NR (Noise Reduction) Amount, Response, Release, and Smoothing.  The user can adjust these controls to achieve a balance between the desired amount of noise reduction and the negative impact on the dialog.  This is definitely more art than science, and it is easily possible to go too far with the noise reduction and actually end up with a clip that sounds worse than before!

     

    Finally, one of the psychoacoustic effects of noise reduction is that listeners perceive the loss of noise as a reduction in high frequencies.  So, BNR offers a high-shelf EQ band that can be used to compensate for this perception.

     

    Like EQ, BNR is a skill that is honed with practice.  It takes experience to learn to recognize when BNR can have a positive impact on a clip, and when it’s a complete waste of time.  But, operating the plug-in properly is something that anyone can do, so don’t hesitate to jump in and give it a try.  And, always remember to save your BNR settings for use latter in a project.  A particular broadband noise problem usually appears several times in the project and the BNR process can become very fast with proper settings management.

     

    In Conclusion

     

    As long people continue making films, there will be problematic production sound. There are a large variety of undesirable sound elements, and quite a few techniques that can be used to minimize them.  Learning when to apply a basic EQ tool and when to bring out the heavy artillery can only be learned through experience.  But with more picture editors being asked to handle the entire sound mix, it’s important to gain a basic level of knowledge to deal with noise.  The good news is that most of the tools of the noise reduction trade are now available to picture editors.  And almost all of the best plug-ins offer a time-limited demo mode.  So get out there and check them out!

     

  • Tue, May 17 2011 7:00 PM In reply to

    • mjolnarn
    • Top 10 Contributor
    • Joined on Wed, Feb 8 2006
    • Sweden
    • Posts 13,346
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    Re: Noise Reduction in Avid Media Composer 5.5

    So BNR will work as a plugin in Audio suite directly in MC 5,5 Soft if I understand you correct, is that so ?

    Mac: 17" Macbook Pro i7 2,66 ghz with 8Gb Ram, 500gb 7200rpm drive___ PC_NEW Win10 Pro Mbo Asus Rampage IV Black CPU Ivy Bridge-E 4960X ( = 12 x 4... [view my complete system specs]

    Tomas 

     

  • Fri, May 20 2011 8:01 PM In reply to

    Re: Noise Reduction in Avid Media Composer 5.5

    How do you access the BNR tool in MC?

    Freelance producer/editor/videographer, Colton Media Productions
    Chief Editor of STP, CTV11

    Specs: MC5.0.3 | AMD Phenom IIx6 1055T Processor (Six cores @ 2.8 GHz, 64-bit) | 8 GB DDR3 RAM | ATI Radeon HD5670 | Windows 7 Pro | After Effects CS4 | Multiple media hard drives

  • Fri, May 20 2011 8:41 PM In reply to

    • Brickwad
    • Top 150 Contributor
    • Joined on Thu, Oct 13 2005
    • Simsbury, CT
    • Posts 950
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    Re: Noise Reduction in Avid Media Composer 5.5

    Very interesting. Thank you!

    1 MC4 Nitris DX on 12 core 2.66 mac pro 6 Gigs of Ram, 2 Symphony Nitris DX on eight core mac pro with 12 gig ram, 3 MC7 on Mac Pro, IMAC, and Macbook... [view my complete system specs]

    WWLD?

  • Tue, May 31 2011 1:46 PM In reply to

    • rethorn
    • Not Ranked
    • Joined on Thu, Oct 13 2005
    • Findlay, Oh
    • Posts 23
    • Points 280

    Re: Noise Reduction in Avid Media Composer 5.5

    Does anyone know why the images don't show up in the post? I think that the topic is inetersting enough and I would like to see the visual settings. Thanks.

    MC 8.X, HP Z640, Dual Xeon 2.20GHz, 32 gigs, Quadro M4000, Mojo DX, Win 7 Pro [view my complete system specs]

     

     

  • Mon, Oct 4 2021 5:50 PM In reply to

    • chuckkahn
    • Top 500 Contributor
    • Joined on Thu, Oct 13 2005
    • Toronto
    • Posts 423
    • Points 4,695

    Re: Noise Reduction in Avid Media Composer 5.5

    Is the Avid Broadband Noise Reduction plugin still installable in MC v2021.9?   I purchased a 7 day rental but the download links in my account at https://my.avid.com/products#MyProducts don't download anything.

     

     

    Avid Media Composer 2018.12.10 / MacOS High Sierra / iMac (Retina 5K, 27-inch, 2017) / 4.2 GHz Intel Core i7 / 64 GB 2400 MHz DDR4 [view my complete system specs]
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