Truncate Silence - problem in cutting identical intervals of silence

Audacity is a great software! Even more for being free! It is admirable the work of people who dedicate themselves to free software with such good will and commitment!
I would like to ask you a little help on using a feature called “Truncate Silence”, with which I am having difficulties.
From what I have learned from your Audacity manual, the “Truncate silence” option should allow us to keep the same interval for several quiet passages. See below:

_Truncate Detected Silence
When this method is selected, silences are simply shortened to the “Detect Silence” duration (see example below).
When this method is selected, the “Truncate to:” (seconds) control is available lower down the interface and the “Compress to:” (percent) control is grayed out.
All detected silences are shortened to the same duration. When the audio remains below the “Detect Silence” level for at least the “Detect Silence” duration, it will be reduced to the “Truncate to” duration entered here.
Extract from:

For example, that all passages with silence above 0.81 seconds are set to 0.8, so that any excess of silence of these passages would be discarded. However, what actually happens when I configure this option is that the stretches do not set at 0.8, on the contrary, 0.8 seconds of each stretch is subtracted. For example, if I have a stretch of 2.8 and another of 1.7, when I apply the “Truncate Silence” with discard to 0.8, in fact these stretches become 1.8 and 1.9, being that both should have stayed with 0.8 and discarded the surpluses 2.0 and 0.9.
A more explanatory table is found below:

So, I would like to ask your help in terms of how I get the update for this feature, which is very useful for me in the audiobook recording.
I notify you that I already tried several plugins like Trim Silence and other suggested ways on the internet, but nothing worked.
I also tried to install all previous versions until 2.0.5 but all have the same problem.Thank you for your help and thank you again for your dedication!

Sounds like you need to raise the detection level on truncate silence: (i.e. use a smaller negative number).

If you look at the waveform in dB scale you will be better able to estimate the threshold level of your “silent” audio …

Linear (default) Vs logarithmic (dB) waveform scale.gif

Dear Trebor,

I appreciate your response, but this really is not my problem.

The problem is that Truncate Silence is subtracting 8 seconds from silence, instead of turning silence into 8 seconds. Observe the two figures to understand better. I wish the error would be corrected, if possible.

Thanks anyway!

I can see in the screenshots in your last post that it is not being truncated to the correct length, but it does not appear to show that it is being truncated by 0.8 seconds. According to your figures the first silence is reduced by 0.79 s and the second silence truncated by 0.47 s.

As a test, so that we can check if we are all getting the same results, please try following these exact steps.
Also, please say which exact version of Audacity you are using (the version number can be found in “Help > About Audacity”).

  1. Launch Audacity
  2. Generate 8 seconds sine tone 1000 Hz, 0.8 amplitude (Generate menu > Tone)
  3. Select the first 4 seconds.
  4. Fade out (Effect menu)
  5. Select the second 4 seconds.
  6. Fade in
  7. Select all (Ctrl+A)
  8. Amplify to New peak amplitude: -13.98
  9. Select from 2.0 s to 6.0 s
  10. Add a label.
  11. Select all (Ctrl+A)
    You should now have a project that looks like this:

12) Apply Truncate silence with the settings:
Level: -20 dB
Duration 0.81
Truncate detected silence
Truncate to 0.8 seconds

The resulting length of my track is 4.8 seconds.
The length of the label is 0.8 seconds.
The project looks like this:

@Trebor Please try this too, and if you have any old versions of Audacity on your machine, please check that you get the same results. (Don’t bother with ancient versions that had the old Truncate Silence effect without the “Action” box).

Dear Steve

Thank you! I did the test I send just below. The result was correct, though different from yours, as you can see, ending in 48 secs instead of 46 s.

I would like to point out that when I use Truncate Silence in a single passage, the result is always correct. The problem appears when I use it in 2 or more stretches of silence.
However, an audiobook has about 10 minutes per chapter, and can total 4 hours of recording, so it would be tricky for me to do the silences reduction one by one.

Once again, thank you for your time!