Identify noises visually
Learn how to identify where problem areas reside in your audio tracks.
Published
Before you can effectively reduce unwanted noises or remove unwanted sounds, you need to be able to take a look at your clips to identify where those problem areas reside.
I'm going to show you how to do that in this lesson.
We're starting off with the noises speech.
This is the same little segment of the Gettysburg Address that I recited.
I've inserted noises into each one, so you can get a sense of I can spot noise problems.
We're looking here at the Spectral Frequency view.
This is the best way to look for noises.
If you switch over to the Waveform view, you really can't spot noises here effectively.
You can sort of tell that something's going on there and maybe something here, but you really can't get a good look at what's wrong with things unless you go to the Spectral Frequency view like that, this little button up there.
Let's take a look at each segment.
You're going to hear that this is just the Gettysburg Address all over again like this.
Four score and seven years ago our fathers brought forth on this continent...
Et cetera...
So that first one obviously has a hum in it, and you can see the hum right down there, that bright yellow line, the yellow line shows areas of strong volume, at that particular frequency and we're down to a low frequency here.
To take a close look at this, I'm going to zoom in in that part of this file, by right-clicking here in the time ruler and then selecting that area, dragging that out, that'll zoom in on it.
Now, you can see that hum a little better.
I want to zoom in here at that lower frequency level to get a clearer look at that hum.
To do that, I just right-click here inside this frequency ruler and just get that spread out a bit.
I get a better look at it.
It's kind of all bunched together.
Well, you can adjust that by right-clicking again, and going down here to Increase Spectral Resolution.
That's Control Shift Up arrow in Windows, Command Shift Up arrow in Mac.
So, I'll do that, I'll do Control Shift Up arrow here, and it's going to be a finer line.
Now, you can get a better sense of how these things work.
You're seeing harmonics here.
I'm going to zoom in here a little bit tighter, right-click again, drag that out.
I can see this, the main line, the brightest line, the loudest line is at 60 Hz.
60 Hz is the kind of hum you get with electrical signals here in North America, elsewhere it'll be 50 Hz.
You see it has harmonics.
The first harmonic typically is double the frequency, that's 120.
And there are other harmonics there as well.
So, it's usually not just one clean tone, it's usually multiple tones.
If we want to fix this, we want to get rid of these various harmonics and get rid of the 60 Hz signal as well.
If we delete this, if I were to select this and delete it, we're going to delete all the speech inside the 60 Hz zone as well.
There are ways around that, particularly using the Sound Remover tool.
All right, I want to zoom back out now.
So, I'm going to first of all, go back to the full view here by doing Control or Command Backslash, that shows the entire file, and this is kind of finely detailed now.
I'm going to change back to what might be considered the default setting.
I can go here and right-click again and do this Decrease Spectral Frequency Resolution one at a time, Control Shift Down arrow.
I'll just do it a few times here, Control Shift Down arrow, Command Shift Down arrow, until it goes back to the default view which is like that.
All right, let's take a look at this next one here.
You can see it's kind of cloudy looking from top to bottom.
I'm going to zoom in in it by right-clicking here, and dragging across there.
When you see something like that, from top to bottom, you're looking at probably hiss, let's listen to it.
Four score and...
That's hiss there, like white noise, with a few other things thrown in.
You see that line riddling in the top there, that's a 15,000 Hz line, just a little bit of a hum, that most folks won't even be able to hear.
I know my dog could hear it, but not everybody else can hear that line up there.
You see my speech down here, that's the bright yellow stuff with all this hiss in between.
Well, to get rid of this hiss, you typically use the Noise Reduction effect.
That's what hiss looks like.
Four score...
Moving down the line here search for some other.
This looks sort of like hiss too because it's covering a lot of frequencies.
You see it tapers off but there's also this bright yellow line down here, so it's a hum and hiss.
This is a commercial fan, a loud commercial fan.
Four score...
So, there's a hum and this hiss.
Our strategy here will be to take care of this hiss first and then deal with the hum later.
Move on down here a little further.
This kind of looks like hiss, but you see those vertical lines there, those are clicks.
This is a vinyl record, so you've got the scratches on the vinyl record, plus little clicks in the vinyl record.
Four score and...
So, to deal with this, you need to get rid of that static and then you work with these individual clicks here.
Let me zoom in on this a bit by right-clicking here and just dragging this out a bit.
And you can begin to see these little clicks here, they are almost to the full frequency length here, from top to bottom, from very high frequency here at the top and a low frequency down there.
And typically, when you work with something like this, you take the Marquee Selection tool, like so, you select that click like that, and there are ways to get rid of that.
You can just drop the volume level on it, or do something called Auto Heal, Auto Heal's right there.
You see that you can make it basically disappear, that click will be gone now, but we still have the static to deal with.
I'll do Control or Command Z, don't do that, and we'll talk about how to do Auto Heal and other things later.
Let's move down the line here, I'm going to zoom this out a bit, so you can see it a little better like that.
All right, we'll go down to the next one here.
So, here it looks a little different.
Let's listen to this one.
Four score and seven years ago our fathers...
And there are little clicks on it, like finger snaps, like that.
You can spot them, they're thicker than the vinyl record clicks. - Let's take a look at this one right here. - Nation...
You can see them showing up there and they're bigger.
I'll zoom in on that one again by right-clicking and dragging that out.
See there's a bigger click there, it has a little bit of sound before, a little bit of sound after with kind of the emphasis in the middle. - I'll play that. - Nation...
It's a little harder to get rid of that because it's a wider sound.
It takes longer, but it can be done as well using that Auto Heal and some other methods.
I'll do a minus here a couple times to zoom back out on that one.
Let's move down to this next example here.
This one has a cough or two in it.
You can spot the cough, it's a wide problem there.
You can see it there, it's not just a spoken word, which should be more like down here and more defined.
It's this wide thing there, let's just listen to that.
Seven years ago...
So, it's a bigger thing, takes longer.
When you got a cough like that inside music for example, it's really hard to get rid of.
Again, speech like this, it's okay if it's in a pause, this one here is in a pause.
I'm not talking there so, it's easy to get rid of that.
But this one here I'm talking.
Very hard to get rid of the cough there when I'm talking.
So, coughs are a problem if you're trying to remove them when something else is going on.
A little bit farther here, this last little segment, you might wonder what the heck is that.
Those are discreet little tones there.
I'm going to select them like this, using my Marquee Selection tool and drag to the right so you can see they're run from about, let's say 1,200 Hz, to about 2,100, 2,200 Hz, kind of a relatively high frequency, but not really high.
It sounds like this. - Ah, it's a cell phone, right.
I've isolated the sound, so you're hearing only those frequency ranges.
So, you can kind of hear me talking in the background.
Actually, a little bit above my speaking voice, so, if I remove those guys, it wouldn't affect the voice too much, but if this were music, it would take a lot of the music out.
So, there are ways to deal with those guys as well using the Sound Remover tool.
This is a different tone up here.
It'll sound a little bit higher, at a higher pitch because that's higher there on the chart.
We can isolate those guys and try to deal with them, but you can see them as well, you can spot those problems too here inside the audio.
Let's take a look at one more clip where you'll see an interesting little sight.
This is a siren.
I'll play it for a moment here.
Over here too.
Pretty easy to see how that works, you got the pitch increasing there and it's a bright line meaning it's pretty prominent, pretty high volume.
But these are the harmonics above it.
So, when you remove unwanted sound, you need to also deal with the harmonics here as well.
So, there you go, that's how you can visually examine sound.
Isn't that kind of cool?
You can look at sound, and see where the problem areas reside.
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