Many times, you'll get a file where the audio is complicated to understand. Maybe this is because the audio file is quiet, and you can't hear it even on maximum volume, or there's a lot of static and background noise in the background. Or maybe the speaker is just talking too quickly for you to understand what they're saying.
So if you encounter any of these issues, there is a way to improve the audio quality, remove background noise, amplify the audio and even slow it down to transcribe it accurately. You might even want to do this step before running the audio through an audio-to-text software tool like otter.ai.
We're going to do all of this with a free audio editor called Audacity. You can download this using a Windows or Mac computer or laptop. So let's go ahead and go to audacityteam.org, then click on download. And from the drop-down list, you can choose Windows or Mac. So let's click Windows.
The most recent version of Audacity is 2.3.3. So click on the audacity 2.3.3 installer, and this will direct you to fosshub.com, where the download files are hosted.
So then, scroll down and click on the Audacity Windows Installer or Mac, depending on your operating system. Then click save file and proceed to follow the instructions on your computer to install Audacity.
So this is what Audacity looks like when you open it up. It might seem a little intimidating at first, but it's simple to use.
And for this demonstration, I'm going to demonstrate how to clean up audio using a file recorded by my grandfather many years ago on a cassette player that I recently converted to mp3.
To do this, you'll need to download the file from whatever platform you're using, but it can be in any audio file format.
We're going to go to File, then click Import, and then click audio. So you're going to locate the file that you want to clean up or improve the audio quality on your computer. Click the file and then click Open.
So I've just imported this file, and as you can see, there are not very big soundwaves. It's actually hushed but what I want to do is I'm going to click on this Zoom tool and then click on the file to zoom in a little bit.
I'm just going to click if this is the selection tool, so if you click anywhere on the audio, you can start playing it. And then, you can press the play button, or you can also press the spacebar on your computer to press play.
First of all, I want to make this louder. So what we're going to do is press Ctrl-A on your keyboard, and as you can see how it's highlighted. So I'm going to click off and again Ctrl-A. It's all highlighted. Then we're going to go to Effect and then click amplify.
I want to make the amplification to -3.0 dB. So this amplified it 12. Just put it to minus three, then click OK. Then it's going to be much louder.
It's much louder, which is good, but we still have this background noise that we don't want, this right here.
What we need to do to remove the background noise is select a background noise sample. And then we're going to tell Audacity, hey, I want you to remove everything that sounds like this.
So let's go to the very beginning. That's a good little sample. Try to make it as long as possible. But maybe in your clip, it might just be a small little sample of static. Or, if you have one that's longer, try to go as long as you can. You can use the selection tool to select this portion of the audio.
And then I'm going to click Effect. I'm going to go to noise reduction, select that, then click get noise profile. Now that's told Audacity. This is the profile of the noise that we want to remove.
Then we want to click Ctrl-A again to select the entire clip. Go back to effect, back to noise reduction. And then click OK. It went through the entire file, and it's removed this background noise. You can see it's removed a lot of that noise.
There's still a bit of a hum in the background, which we can even try to do it again if we want. So I will try you another time, get a noise profile and do the same thing again.
And if you want to keep trying throughout the clip different noise profiles to remove that staticky background sound, you can keep doing that.
I don't understand what he's saying, so I want to make this go a little bit slower. If that's your issue, you can again click Ctrl-A, then go back to Effect, click change tempo. And what this will do is we'll change the tempo without changing the pitch.
It has made it slower, so we can understand even more so you can even go down further if you want to make it even slower. Then all you have to do is click OK.
What you can do if you want to save this as an mp3 file because maybe now you want to put it in otter.ai and transcribe it. So it's clearer for otter.ai or another transcription software to transcribe it to text. You can click File, Export, and then choose Export as mp3 or Export as WAV file.
So that is the way to clean up the background noise and increase the volume of the clip. And also you can change the speed. I hope you enjoyed this tutorial, and I hope that this helps you transcribe and understand what the people are saying in these files that you are transcribing.