How to remove below a threshold volume

Audacity Help Forum Windows
1

Hello, I’m French so my english is not very good, forgive me :slight_smile:

I have some problem with audacity, i want to do two things :

  1. My audio file lasts 3 hours and for my job i have to listen this audio file but there is a lot of useless information in the file. Indeed there is a background i want do completely remove (hence cut the file when the volume is too low). How can i do that? The background is approximately two times lower than the interesting information.

You will better understand if i explain the job : A man is next to the road and when a car passes he has to speak the licence plate in a mike (for statistics of the road). My job is to enter in a Excel file the licence plate i listen in the mp3 file (3 hours file).

So i think that if i remove the volume which are for exemple two times lower than the voice of the man i can reduce the file to 1 hour.

  1. Maybe with removing every frequencies which do not correspond to a man voice i can improve again the length of the file.

Thank you for your help and ideas :slight_smile:

2

You want to do two jobs. Noise Gate will recognize quiet segments and reduce the volume to zero, but it doesn’t make the show any shorter.

Then software that recognizes dead silence and deletes it from the show. I think there’s a tool to do that. I need to look.

Koz

3

Analyze > Silence Finder.

The tool which deletes the silences may be a custom tool.

Here’s one. Everything in one tool.

http://manual.audacityteam.org/o/man/truncate_silence.html

Koz

4

I have to use Noise Gate then the second tool. Indeed silent truncation only truncate under -20dB.
But i think i’ve got what i want. Thanks a lot!

5

What about trying this:

Select an area that is quiet. Go to Effects —> Noise Removal. Select Get Noise Profile.
Select whole track (CTRL A) and then go Effects → Noise Removal–> Okay.

This should make all the quiet spots absolute silence.

Then use Koz’s suggestion to get rid of it.

Only reason I think of doing noise removal first is due to ambient noise of the person who is recording, they may move around etc.

Damien

6

With Noise Removal + truncation silence + Noise gate the result il pretty good :slight_smile:

We hear especially the cars, and the wind.

I you have another idea to improve the result you’re welcome :slight_smile:

Thank you.

7

Stop telling people you have bad English. We have zero trouble understanding you and what errors there are, you can put down to fat fingers on a cellphone.

Koz

8

Apply a high pass filter at about 150 Hz as the first step - this will reduce “rumble” from traffic noise and so may improve your results.

9

You can slide back and forth between 80, 100, and 150 Low Cut Filter. Nobody here would dream of recording live voices without the 100Hz cut filter. 80 is very gentle and 150 may be too aggressive for you. Experiment on a known voice track with the High Pass Filter and all three values. What kills you, of course, is your speakers or headphones have to be able to do 80 Hz to be able to hear what you’re doing.

The first time you walk into a large sound system: “Good night! What’s that rumbly Metrobus sound in my show?”


I’m just now looking. I have a good voice microphone with 40, 80, and 160 low cut filters built-in, and a tiny field mixer with the choice of 80 and 160. The Shure A15HP is a “100 Hz cut” filter and the filter on the Peavey mixer is 80Hz.

I think 150 is too aggressive. That will turn your ballsy, broadcast announcer into a normal speaker with good diction. You need to judge yourself.

Koz

10

which in this case is probably ideal:

“You will better understand if i explain the job : A man is next to the road and when a car passes he has to speak the licence plate in a mike (for statistics of the road). My job is to enter in a Excel file the licence plate i listen in the mp3 file (3 hours file).”