Use the Spectral Frequency Display to clean up your audio

Waveform displays give you a pretty good indication of what's going on in terms of time with your audio recordings.

But the Spectral Frequency Display is where it's at for identifying problems within a specific frequency range.

Now let's open up here under Assets, under the Clean up directory I have.

Let's open up this Interview-Noise_audio.wav file.

And if you listen really carefully - I'll just click a little bit in from the beginning here.

And I'm going to play this.

I'm pressing the spacebar to play.

And just have a listen around about this region, if I just pull this down - and have a listen.

So there's definitely a telephone ringing in the background here.

And in fact as we go on, the audio gets even worse.

We've got a terrible hiss and there's a high-pitched whine.

Pretty awful.

Now with the waveform display we can see where the problem is in time, but we can't see specific frequencies.

So I'm going to pull up this divider to display the Spectral Frequency Display.

And now it becomes pretty clear what's going on.

I'm going to resize the panel a bit here.

Let's just get rid of our waveform altogether.

And I'll maybe pull the heads-up display over out of the way.

Here is our telephone.

And it's pretty obvious, because it's a man-made signal.

And so it doesn't have that organic subtlety and nuance of speech patterns which is all the rest of this sound.

If I play this through again, you can see very clearly where the telephone is.

And there's all that noise.

You see all that fuzzy pink stuff.

That's the background noise.

And this thin line along the top, that's the high-pitched whine.

Who knows maybe that's come from some radio interference.

Whatever it is, we want to get rid of it.

With the Spectral Frequency Display all we have to do is find a way of highlighting, identifying the section we want to remove, and we can get rid of it.

And to do that we can use any of these 4 tools along the top.

Not the Healing Brush tool.

But any of these four will allow us to make a selection.

Now using the I-beam isn't much good.

It's going to take all of the frequencies.

But I noticed that this telephone ring tone it's pretty much in a box pattern.

So rather than going to the trouble of using the Lasso tool, it's kind of difficult to get a clean square shape with it.

And without even using the Paintbrush tool which... well even if I shrink it down a little bit, just click and drag here on the size.

Now it's kind of not so easy to make a straight line.

I'm going to pick out the Marquee and I'm going to draw a box.

In fact, before I do this, I'm going to scroll with the mouse wheel just a little, position my playhead in the center of that phone ring to make it a little bit larger.

And then I'm going to position the mouse on the far right.

And I'm going to make it a little bit taller.

So I'm scrolling with the mouse wheel to zoom into the frequency range and also the time range.

I've got a really big selection here.

Now I'm just going to click and drag the Marquee over these markings.

And if I want to I can use the heads-up display to drop the volume incrementally.

But I'm just going to hit the Delete key.

And I'm removing those frequencies.

And before I click away to deselect the Marquee, notice that Audition CC has automatically smoothed the edges of the selection.

It hasn't just created a kind of a frequency cut-out.

I've got smoothing there - let's just deselect so you can see it - to soften the join between the absent and the remaining frequencies.

So now I'm going to scroll down with my mouse to zoom back out.

I'm going to scroll down on the Frequency scale to do the same, click back a little bit and have another listen.

Perfect.

Now I'm going to do the same thing up here.

Let's just zoom in a little bit in time, maybe not that much, scroll over a little.

I'm going to be kind of lazy here.

You could be a bit more accurate perhaps.

Select that high band.

Notice that I'm getting both the left and the right.

Now if I use my up and down arrow keys, I can selectively exclude or include one channel or other.

This is just the up and down keys on my keyboard.

I'm going to hit Delete.

Click away.

And now let's have another listen.

So we've lost that high-pitched whine, let me just zoom out again.

We've lost the telephone ring and now we're ready to move on to perhaps more advanced noise reduction techniques to get rid of that hiss.

So again the Spectral Display in Adobe Audition CC makes this kind of very specific work within tight ranges of frequencies much easier than trying to locate them through trial and error, just using the waveform display.