I need to generate recordings of sounds made by mechanical equipment. These sounds occur randomly every few hours, and only last approximately 1-3 seconds.

Ideally, I would like software that can perform that exact task. I have not been able to find such an app, so I posted this question (and placed a bounty on it!). While I wait for an answer, I was thinking about other ways to obtain the needed recordings.

Is anyone aware of software for either or that can process a 2-12 hour recording and automatically delete all time periods that have no audio?

Ideally, I would like to set the dB threshold that defines "no audio".

Also, ideally, I would like to be able to specify the amount of empty audio before and/or after each fragment that is kept. For example, keep 1 second of empty audio before each fragment that is used.

Since I have not yet generated these recordings, I am open to using any audio file types for which I can find a recorder.

I would like software (freeware) for this task.

  • Can it be a phone app? there are some alarm apps out there that are able to record a person's snoring and sleep-talking during the night while skipping the silence
    – Tymric
    Commented Oct 3, 2015 at 18:02
  • @Timmy Yes, an Android app will work great. Your idea is an interesting and unique one... perhaps you can add an answer to softwarerecs.stackexchange.com/questions/23261/… (I am currently offering a Bounty) Commented Oct 3, 2015 at 18:51
  • While it seemed a good idea at first, most of such apps do not have give out detailed information on how they record. The ones that do seem to only save sounds that are longer than 5 seconds
    – Tymric
    Commented Oct 3, 2015 at 19:20

1 Answer 1


I suggest Audacity. You can load wave or mp3 files (among other formats). Select the track and then go to the menu Effect->Truncate Silence... Here you can specify a decibel threshold and also a duration. Also you can specify how much to truncate it to. I found 0.1 seconds sounds better than 0 seconds

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Here's a youtube video on it although it's for an older version of audacity so the interface has changed some since then:

Truncating Silence with Audacity

In fact anytime you are looking for a free app for some audio functionality I recommend seeing if audacity will work.

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