Free shipping in the U.S. — Click here for details .
Sign in Join now
Lightspeed AviationLightspeed AviationLightspeed AviationLightspeed Aviation
    0
  •   was successfully added to your cart.
  • Shop
    • All Products
    • Headsets
    • ANR for Helmets
    • Flight Bags
    • Accessories
    • Survival
    • Lightspeed App
    • FlightLink App
    • Authorized Dealers
    • Trade Up Program
  • About
    • About Lightspeed
    • Programs
    • Delta Zulu Saves Lives
    • Awards and Accolades
    • Patents
    • Lightspeed Foundation
    • Careers
    • Associations
  • Community
    • All Posts
    • Blog Posts
    • Events
    • News
    • Sponsorships
  • Support
    • Customer Support
    • Repair Request
    • Frequently Asked Questions
    • Shipping and Return Policies
    • PFX Firmware Update – PC
    • PFX Firmware Update – Mac
  • Contact
    • Contact Lightspeed
    • Authorized Dealers
    • Donation Requests
    • Media Kit
Sign in / Create Account

ANR 101: Section 3 – Airplane Issues 

    Home ANR ANR 101: Section 3 – Airplane Issues 
    NextPrevious

    ANR 101: Section 3 – Airplane Issues 

    By Lightspeed Aviation | ANR, ANR 101, Blog Posts | 0 comment | 7 August, 2018 | 0

    Section 3: Airplane Issues 

    Looking at actual cockpit noise profiles, and how well aviation headsets cope with it 

    In Section 2 of this series, you learned how engineers measure effectiveness of active noise canceling systems in the laboratory. But since we don’t fly in the lab, our emphasis will now shift to studying the actual noise spectrums in various aircraft to focus on what ambient noise we’re trying to cancel, and how serious a threat this noise poses to our hearing. Clearly, we want our aviation headset to cancel noise most effectively in the areas of the spectrum where there is the most noise! We’ll look at some actual noise profiles in piston-powered single-engine cockpits, and see how well passive and active headsets deal with it. 

    Noise profiles 

    Let’s start by reviewing some actual detailed noise data for two different single-engine airplanes. Below is data measured during flights in a Cessna 210 and a Piper Commanche.  

    Having analyzed dozens of aircraft noise spectrums, we know that these profiles are typical of most makes and models of single-engine planes. The noises generated by the propeller and its resonant (harmonic) frequencies make up the most predictable part of the noise spectrum. 

    The Commanche had a two-bladed propeller that creates its peak noise levels at about 80 Hz, while the Cessna 210 has a three-bladed propeller with a peak noise level at around 120-130 Hz. Engine, exhaust, and wind noise add most of the rest of the sound in the noise profile. Obviously engine size, aerodynamics, and many other aircraft-specific design features contribute to the actual profile of any specific plane. 

    While these two planes look different in many ways, there are two general characteristics that are evident: 

    1. There is a lot of noise in the low frequencies…between 70 and 300 Hz. 
    2. Noise levels decline in the higher frequencies…particularly beyond 500 Hz.  

    Both these characteristics create a perfect fit for using active cancellation for optimal sound reduction. Remember (from Section 2) that active cancellation works well only in the lower frequencies… it doesn’t provide a noticeable dB reduction at frequencies over 500 Hz. Recall also that active systems require some tradeoffs in passive attenuation to support the needed modifications inside the domes. As such, they are not quite as effective in blocking out the higher frequency noise. 

    But isn’t high-frequency hearing protection more important? 

    That all depends on both the level of noise and the duration you are exposed. In Section 2, we covered the “A-weighted” and “C-weighted” NRR measurements. The conclusion was that high levels of low frequency sound could actually be more damaging than the higher frequency noise. As you can see from the airplane noise spectrum graph, there is usually 20-30dB more noise at 100 Hz than at 1,000 Hz in a piston-engine airplane. 

    Typically people are focused on hearing damage and “saving what they have left.” That’s a key reason they’re interested in getting a new headset. Prolonged exposure to noise has a variety of effects on the nineBlack and brain that have daily and direct effects on your ability to fly a plane safely. (Section 5 of this series will cover those issues in more detail.) Meantime, it’s sufficient to state that active noise reduction headsets create both a quieter and safer environment for your ears. 

    What we know about hearing loss 

    The data relating to hearing loss is actually the simplest to understand and has been well studied. Below is the data gathered from studies done by the EPA correlating levels of noise to the length of time the subject is exposed. 

    Projected hearing loss from continued noise exposure.  

    These figures were calculated assuming exposure to the given level of noise for eight hours a day, five days a week. Not surprisingly, more noise for longer times means greater risk of hearing loss. But the most interesting piece of data here is that there is no projected loss from exposure to 80 dB for eight hours a day, and even 85 dB results in just nominal hearing loss. The real damage begins to develop with prolonged exposure to levels above 90 dB. 

    We’ve seen that in propeller aircraft, noise of this intensity occurs only at low frequencies. Now you can see why it is so important to reduce the very low frequencies. 

    Why ANR works so well in aircraft 

    One of the reasons active cancellation is so effective in airplanes is just this: there is lots of low frequency noise. The graph below is a smoothed output of the takeoff noise spectrum of a Cessna 172RG Cutlass. It has a similar profile to the planes we looked at earlier this section. 

    Effects of typical passive cancellation on noise spectrum.
    (Cessna Cutlass with adjustmentsfor passive
    cancellation over the full spectrum.)  

    The lower line is there to represent the attenuation you can expect from a typical passive headset. Note how poor the attenuation is at 100 Hz and how much better it gets at the higher frequencies. While there is substantial quieting at 1,000 Hz, you’re still exposed to levels well over 80 dB at the lower frequencies. 

    As we’ve seen, passive hearing protection is very effective where there is less noise, or where the noise is predominantly at higher frequencies. It’s just not the ideal solution for an aircraft noise environment. 

    Compare that to the protection provided by excellent active cancellation in the low frequencies. 

    ANR’s additional low-frequency hearing
    protection over passive headsets. 

    This is a close-up of that same Cutlass noise spectrum focusing just on the low frequency area. The red line shows the additional attenuation provided with active cancellation over a typical passive headset. That reduction is very noticeable. Understand that there will be a slight reduction in higher frequency attenuation with ANR headsets. This is generally a good tradeoff because the residual cockpit noise levels are already very low at higher frequencies…well below any levels which can cause damage. 

    So where are we? 

    You should now have a good understanding of the noise levels and spectrum we live in as pilots. The high-decibel, low-frequency components are not effectively removed by a traditional passive headset. In contrast, active cancellation is specifically designed to reduce this portion of the noise spectrum and get it well below the hearing damage thresholds. All of that creates a quieter, safer, more relaxing environment to enjoy during your time aloft. 

    In the next section, we’ll change gears and turn from noise to comfort. I don’t know a single pilot who wouldn’t like to have a more comfortable headset. But until the advent of ANR headsets, the words “headset” and “comfort” were not normally uttered in the same breath!! Our next section will focus on the ergonomic issues that affect the level of comfort of a headset. We’ll examine the wide range of variables that make getting a comfortable headset something akin to the search for the Holy Grail! We’ll also cover user features like battery box sizes, controls, and accessories that effect ease of use. 

    Go to Section 4 >> 

    active noise, ANR, ANR performance, attenuation, Cessna, Cutlass, frequency, headset, high frequency, low frequency, noise cancellation, noise profile, passive, passive noise, spectrum

    Lightspeed Aviation

    Lightspeed Aviation is a leading manufacturer of premium aviation headsets and helmet products. Since the first product was introduced in 1996 at AirVenture in Oshkosh, WI., the company has established a reputation for leading innovation in the aviation headset marketplace with a number of “first to market” advances, technologies, and features. In 2022, the company launched a new category of aviation products called “Safety Wearables”. Layering life-saving technologies on top of their award-winning audio and ANR platform, Lightspeed ushered in a new era of aviation safety. With this, the company continues to live its mission of “creating products that protect and save lives”. Additionally, Lightspeed is a passionate supporter of initiatives to encourage the next generation of pilots through its support of programs like Young Eagles and Ray Scholars. The company is proud to have participated in helping countless young people experience everything from a discovery flight to getting a Pilot Certificate.

    More posts by Lightspeed Aviation

    Related Posts

    • ANR 101: Section 4 – Ergonomic and Interface Issues 

      By Lightspeed Aviation | 0 comment

      Section 4: Ergonomic and Interface Issues  In this section, we’ll be looking at the comfort and human-factors issues associated with ANR headsets. The ergonomics of the human head demand a wide range of adjustments toRead more

    • ANR 101: Section 2 – Acoustic Issues 

      By Lightspeed Aviation | 0 comment

      Section 2: Acoustic Issues  Understanding and comparing cancellation specifications  Section 1 of this series dealt with the variables and complexity involved in canceling the repetitive and random aspects of airplane noise. It explained that althoughRead more

    • ANR 101: Section 1 – The Basics of ANR 

      By Lightspeed Aviation | 0 comment

      Section 1: The Basics of ANR  A good place to start is with one of the most-asked questions that we receive from pilots:  Don’t all active Pilot Headsets work the same way… or do theRead more

    • ANR 101: A Tutorial on Active Noise Reduction 

      By Lightspeed Aviation | 0 comment

      A Tutorial on Active Noise Reduction  by the technical staff of Lightspeed Aviation  This is a five-part series on Active Noise Reduction in General Aviation. It came about because hundreds and hundreds of you haveRead more

    • ANR for Helmets by SocialFlight’s T-51 Mustang Aircraft Build

      By Lightspeed Aviation | 0 comment

      Our friends over at SocialFlight have been hard at work with their T-51 Mustang Aircraft Build. So when they took a minute to discuss their helmets from FlightHelmet.com with the Zulu H-Mod installed, we took notice.Read more

    Leave a Comment

    Cancel reply

    Your email address will not be published. Required fields are marked *

    NextPrevious

    Recent Posts

    • Critical Comms: The Importance of Clear Hearing in Aviation
    • Why don’t my soft goods last longer?
    • Pilot’s Missions are a Chance to Give Back
    • Why can’t my legacy Lightspeed headset be repaired?
    • Flying as an Act of Faith

    Join Our Newsletter




      Top Rated Products

      • Zulu 3 - Pilot Headset - LightspeedAviation.com Zulu 3 ANR Headset
        Rated 5.00 out of 5
        $899.00
      • Markham Flight Bag - LightspeedAviation.com Markham Flight Bag
        Rated 5.00 out of 5
        $249.00
      • Sierra® ANR Headset - Pilot Headsets - LightspeedAviation.com Sierra® ANR Headset
        Rated 4.80 out of 5
        $699.00

      Lightspeed Aviation, the leader in wearable ANR technology for pilots, operates with a simple strategy: know your customer well and remain committed to relentless product evolution. At Lightspeed, everything we do is in service to our customer and our products push performance to the edge of technological possibilities.

      Stay Updated – Sign Up Here




        Information

        • Contact
        • Support
        • Frequently Asked Questions
        • Privacy Policy
        • Home
        • Shop
        • About
        • Community
        • Support
        • Contact
        © Copyright 2022 | All Rights Reserved
        • Shop
          • All Products
          • Headsets
          • ANR for Helmets
          • Flight Bags
          • Accessories
          • Survival
          • Lightspeed App
          • FlightLink App
          • Authorized Dealers
          • Trade Up Program
        • About
          • About Lightspeed
          • Programs
          • Delta Zulu Saves Lives
          • Awards and Accolades
          • Patents
          • Lightspeed Foundation
          • Careers
          • Associations
        • Community
          • All Posts
          • Blog Posts
          • Events
          • News
          • Sponsorships
        • Support
          • Customer Support
          • Repair Request
          • Frequently Asked Questions
          • Shipping and Return Policies
          • PFX Firmware Update – PC
          • PFX Firmware Update – Mac
        • Contact
          • Contact Lightspeed
          • Authorized Dealers
          • Donation Requests
          • Media Kit
        Lightspeed Aviation
          0 items
        We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept”, you consent to the use of ALL the cookies.
        Do not sell my personal information.
        Cookie SettingsAccept
        Manage consent

        Privacy Overview

        This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.
        Necessary
        Always Enabled
        Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously.
        CookieDurationDescription
        __cfruidsessionCloudflare sets this cookie to identify trusted web traffic.
        __hssrcsessionThis cookie is set by Hubspot whenever it changes the session cookie. The __hssrc cookie set to 1 indicates that the user has restarted the browser, and if the cookie does not exist, it is assumed to be a new session.
        _GRECAPTCHA5 months 27 daysThis cookie is set by the Google recaptcha service to identify bots to protect the website against malicious spam attacks.
        ci_session2 hoursThis cookie is set as default session Cookie name in config.php in config folder in CodeIgniter.
        cookielawinfo-checkbox-advertisement1 yearSet by the GDPR Cookie Consent plugin, this cookie is used to record the user consent for the cookies in the "Advertisement" category .
        cookielawinfo-checkbox-analytics11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
        cookielawinfo-checkbox-functional11 monthsThe cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
        cookielawinfo-checkbox-necessary11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
        cookielawinfo-checkbox-others11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
        cookielawinfo-checkbox-performance11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
        JSESSIONIDsessionThe JSESSIONID cookie is used by New Relic to store a session identifier so that New Relic can monitor session counts for an application.
        PHPSESSIDsessionThis cookie is native to PHP applications. The cookie is used to store and identify a users' unique session ID for the purpose of managing user session on the website. The cookie is a session cookies and is deleted when all the browser windows are closed.
        viewed_cookie_policy11 monthsThe cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.
        Functional
        Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features.
        CookieDurationDescription
        __cf_bm30 minutesThis cookie, set by Cloudflare, is used to support Cloudflare Bot Management.
        __hssc30 minutesHubSpot sets this cookie to keep track of sessions and to determine if HubSpot should increment the session number and timestamps in the __hstc cookie.
        Performance
        Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors.
        Analytics
        Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc.
        CookieDurationDescription
        __hstc1 year 24 daysThis is the main cookie set by Hubspot, for tracking visitors. It contains the domain, initial timestamp (first visit), last timestamp (last visit), current timestamp (this visit), and session number (increments for each subsequent session).
        _ga2 yearsThe _ga cookie, installed by Google Analytics, calculates visitor, session and campaign data and also keeps track of site usage for the site's analytics report. The cookie stores information anonymously and assigns a randomly generated number to recognize unique visitors.
        _gat_gtag_UA_28458117_11 minuteSet by Google to distinguish users.
        _gid1 dayInstalled by Google Analytics, _gid cookie stores information on how visitors use a website, while also creating an analytics report of the website's performance. Some of the data that are collected include the number of visitors, their source, and the pages they visit anonymously.
        CONSENT2 yearsYouTube sets this cookie via embedded youtube-videos and registers anonymous statistical data.
        hubspotutk1 year 24 daysHubSpot sets this cookie to keep track of the visitors to the website. This cookie is passed to HubSpot on form submission and used when deduplicating contacts.
        Advertisement
        Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. These cookies track visitors across websites and collect information to provide customized ads.
        CookieDurationDescription
        _fbp3 monthsThis cookie is set by Facebook to display advertisements when either on Facebook or on a digital platform powered by Facebook advertising, after visiting the website.
        fr3 monthsFacebook sets this cookie to show relevant advertisements to users by tracking user behaviour across the web, on sites that have Facebook pixel or Facebook social plugin.
        VISITOR_INFO1_LIVE5 months 27 daysA cookie set by YouTube to measure bandwidth that determines whether the user gets the new or old player interface.
        YSCsessionYSC cookie is set by Youtube and is used to track the views of embedded videos on Youtube pages.
        yt-remote-connected-devicesneverYouTube sets this cookie to store the video preferences of the user using embedded YouTube video.
        yt-remote-device-idneverYouTube sets this cookie to store the video preferences of the user using embedded YouTube video.
        yt.innertube::nextIdneverThis cookie, set by YouTube, registers a unique ID to store data on what videos from YouTube the user has seen.
        yt.innertube::requestsneverThis cookie, set by YouTube, registers a unique ID to store data on what videos from YouTube the user has seen.
        Others
        Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet.
        CookieDurationDescription
        ppwp_wp_session30 minutesNo description
        Save & Accept