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When playing some deep sounding audio files, it sometimes happens that the speakers/headphones crack. This happens randomly across various operating systems, audio players and speakers/headphones.

The crack noise is not part of the audio recording. And if it happens, it always happens just a fraction of a second after playback started. Question now is, what causes it and how can it be fixed in Audacity or Garage Band?


Normalizing the whole audio file in Audacity to -13 dB makes it less likely that the crack sound happens, but does not reliably fix the issue. It also has the side effect of lowering the volume too much, so it's not a good fit.

Audacity's Spectogram view shows a bright white line on the frequencies between 250 and 400 Hz. Using Audacity's Graphic EQ and setting these frequencies to -20 dB (minimum value) colors the bar yellow, but still occasionally causes the clip to crack and also lowering its volume too much, so it's not a good fit neither.

Unfortunately I'm having zero knowledge of signal processing, and only some basic knowledge of Audacity/Garage Band, so your advise on how to get rid of this cracks is very much appreciated. Thank you.

Edit: Here's an example wav file.

Edit 2: File removed from server. At the end, the decision was made to simply not use the troublesome audio clips. Thank you very much for all the advise.

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  • Can you post a file up somewhere easily accessible? [& downloadable]
    – Tetsujin
    Apr 10, 2023 at 8:44
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    I can make it click on everything I've tried it on, including my main studio monitors, at almost any level. Trying to analyse it/EQ it, but I'm getting nowhere fast. I've had it in 3 apps, of increasing complexity, Audacity, Izotope & Cubase. I think long & short is, if you're going to generate a sine, do it in mono, there are some odd phasing issues in your stereo. Better still, don't use a pure sine.
    – Tetsujin
    Apr 10, 2023 at 11:57
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    I think there's something oddly 'mathematical' going on, which as a music engineer, not a boffin in a lab coat, I don't have the gear to analyse properly. As I can repro the issue at any volume, I get the feeling something is upsetting my DACs, rather than speakers, but I can't 'prove' anything concrete. Nothing untoward registers on any app's output meters or frequency analysis.
    – Tetsujin
    Apr 10, 2023 at 12:08
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    I'm honestly stumped. I can't see anything 'wrong' with it, right down to visually checking the waveform, checking the 'obvious' like DC offset, changing EQ, running it through tape & valve emulations to blur the edges..., but everything I own hates it. My studio DACs object to it even right down at -20dB on the master outs, but then relies on how loud I have the analog stage. Quiet as a mouse - fine. Anything moderately louder, crackle. [This is a multi-thousand pound pair of active bi-amped monitors. I've never known them object to wall-bending rock music, just this weeny sine wave]
    – Tetsujin
    Apr 10, 2023 at 17:11
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    I'm late to the party and didn't get to listen to the sound (already deleted when I saw the question). From the conversation so far I suspect, as Tetsujin stated, that it must be something going on either on the digital domain (I believe it should be visible in the waveform though) or on the transition from the digital to the analogue domain (DAC). I don't have much knowledge on digital formats (I do know more about coding schemes though) and wonder if there were any possible issues with metadata about the file (although I don't think this would be very probable).
    – ZaellixA
    Apr 16, 2023 at 8:47

1 Answer 1

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To my observation this can be due to overloading the output, which certainly depends on the program you are using.

If you recall the theorem of adding two sine waves you‘ll recall:

  • for two low frequencies (viewed from playing low close notes) it‘s easier to add to a high amplitude than it is for higher pitches
  • we may tend to provide higher amplitudes for lower frequencies to compensate for our loss of sensitivity (frequency and age)

BTW, can‘t hear any cracks from your file on my ipad.

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    Thanks for your help! It looks like it highly depends on the speakers. On Sennheise CX Plus for example, it happens rather frequently. On some smartphone speakers (iOS and Android) it happens rarely, while on a very few devices, it happens so often that the clip is unsuitable. Apr 10, 2023 at 10:37
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    Right, overloading speaker, i.e. make them bounce against something, is another source. If you compare it, e.g. by a frequency sweep, handheld devices like i-thingies have a high pass at frequencies around 400 Hz or so. I.e. they dampen lower frequencies, i.e. might sound crackless, while a HiFi device or a simple headset might spot crack after crack.
    – MS-SPO
    Apr 10, 2023 at 13:25

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