Finally! iOS 6 kills the filter on headset and mic inputs!

So, iOS 6 has finally arrived and the biggest news for SoundMeter, SignalScope, and SignalScope Pro users may just be that the high-pass filter which used to plague the built-in microphone and headset microphone inputs now gets bypassed. This exciting improvement to iOS 6 will significantly improve the quality of acoustical measurements that can be made with the iPhone, iPad, or iPod touch, without requiring a dock connector accessory for audio input.

Below are 1/3-octave headset input frequency response comparisons for the various iOS devices that support iOS 6. More details regarding the headset input and built-in microphone will be presented in the days ahead.

Update (9/19/20120, 7:32 PM): It should be noted that these are electrical frequency response measurements. When making acoustical measurements, the overall frequency response will depend also on the microphone that is used.

iPhone 4S Before iOS 6/Now

iPhone 4S Headset Leq Pre-iOS 6  iPhone 4S Headset Leq iOS 6

iPhone 4 Before iOS 6/Now

iPhone 4 Headset Leq Pre-iOS 6  iPhone 4 Headset Leq iOS 6

iPhone 3GS Before iOS 6/Now

iPhone 3GS Headset Leq Pre-iOS 6  iPhone 3GS Headset Leq iOS 6

iPod touch 4 Before iOS 6/Now

iPod touch 4 Headset Leq Pre-iOS 6  iPod touch 4 Headset Leq iOS 6

iPad 3 Before iOS 6/Now

iPad 3 Headset Leq Pre-iOS 6  iPad 3 Headset Leq iOS 6

iPad 2 Before iOS 6/Now

iPad 2 Headset Leq Pre-iOS 6  iPad 2 Headset Leq iOS 6


iOS 6 is now highly recommended for all SoundMeter, SignalScope, and SignalScope Pro users.




  • David Nedrow

    Hooray! I am just getting ready to install a new cinema sound processor and will need to calibrate it and EQ the auditorium.

  • Robert Hedeen

    I just got iOS 6 pushed onto my iPhone 4. Do I need to download a new version of Soundmeter to take advantage of the better frequency response of the internal mike? I have Soundmeter ver. 3.1.5

    • ben

      Ever since it was updated for iOS 5, SoundMeter has used the measurement mode in iOS. It’s this measurement mode that disables the high-pass filter. SoundMeter 3.1.5 is good to go.

  • Martin


    I’m desperatly trying to get the correct frequency output from my iPhone microphone…

    Is there a special function in the AudioUnit framework, which is used to turn the filter off?

    Best regards


  • Leonardo

    ios6 brought many new things for audio developments…
    By the way, is it possible to select which mic to use having a headset plugged? I need to switch between internal and external mic…


  • Darran

    Hi. Do you think soundmeter with a proper mic could gain type approval, perhaps type 2? That would be very useful as the UI makes it preferable to cryptic handheld meters.

    Also, would it be possible to save csv data to allow for statistical analysis, eg La90 background noise levels?


    • Lee

      Do you know if there are any audio recording apps that make use of this measurement mode feature to disable the high-pass filter? This seems to be happening to me when I record audio using GarageBand, SoundCloud, etc.

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