Is there a way to throw out anything which is not speech? The track has only background noise, silence and speech.

We need to isolate parts of an audio track that have speech. Speech is clearly visible on the spectrogram, but not on the Decibel scale. That's why "Truncate Silence" fails every time with filtering spoken parts that aren't all that loud.

The problem is clearly defined in this sonogram: yes no spectrogram filter Kill the left hand box! Remove that which has no spikes! Keep the right one.

I'd cut it out with scissors but the tape is just too long to do it manually.

We need to send hours of audio to a transcriptionist but it has long silences inbetween. We don't want to pay for those.

I have access to a DAW with "Audition", "Sox" and other weird alien software installed. I know basic multimedia editing but Audio is not my field. Been fiddling around with this for over an hour but can't do it.


2 Answers 2


Use a noise gate with a fast attack and medium release. So long as the threshhold is above the floor noise/background noise, it will cut off any sound during the silent parts of the track. There are other ways such as noted below, in Cubase its called a "DeNoiser". However, it comes at a slight sacrifice of certain frequencies within the audio, so I would recommend you go with a Noise Gate or possibly re-record the audio being close to the mic. Watch for 'plosives if its vocals.

There of course is also the long winded way. Chop out all the audio where you aren't talking.



If you have ProTools you can use the strip silence function to remove everything below a certain dB threshold.

If your you can use noise gate plug-ins and render them into your sample. A noise gate reduces the volume (to silence) whenever the sound goes below a certain threshold.

Good Day

  • the problem is that the recording is made with auto gain control. That means that in silent parts the background noise increases to the same decibel level. So a decibel threshold is of no use.
    – user310545
    Commented Mar 25, 2014 at 22:44
  • They you could use a Denoiser and insert it into the side chain of a noise gate => The noise on the trigger signal will be reduced => Nosiegate only works where noise is present. Commented Mar 26, 2014 at 9:36

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