![]() ![]() The reason this helps is that not all hum fills all harmonics. ![]() Most often, hum generates harmonics, which occur at mathematically precise intervals above the base frequency.Ĭhange the number of harmonics to the smallest number that still eliminates the hum. However, most hum is not a pure tone centered on 60 Hz (or 50 Hz, depending). For most of the rest of the world, set this to 50 Hz. ![]() Set the frequency to match the frequency of your electrical power source. Generally, there are only two settings here that you need to adjust: This opens the controls window for DeHummer. With the clip you want to correct open in the Waveform Editor, choose Effects > Noise Reduction/Restoration > DeHummer. NOTE: For final mixes or multiple clips, though, the Multitrack Editor is the better choice because it allows non-destructive editing, which means you can change your mind later without damaging the clip. (See the Summary below for the reason why this isn’t as bad as it sounds.) The Waveform Editor does what’s called “destructive” editing,” in that the changes are saved directly into the clip. This is the perfect place to clean up a single clip because any changes you make are immediately saved into the clip. In just a second or so, the clip is displayed in Audition’s Waveform Editor. Personally, I love the smooth integration between Audition and Premiere. NOTE: If you want to move your entire project to Audition, for example to do the final audio mix, select Edit > Edit in Adobe Audition > Sequence. Select the clip you want to fix in the Timeline and choose Edit > Edit in Adobe Audition > Clip. Buried in some very loud hum is our interview the audio is so low that it barely peaks above the waveform. Now you’ve got audio hum in all your scenes.Īdobe Audition has a great hum removal tool and, while it can be used by any NLE, it is easiest from inside Premiere. Or maybe if the Bach Cello Suite was a soccer game, and the tone was the sound of thousands of Vuvuzelas?įor more information on that last one, and how you just solved a problem that real television broadcasting sound engineers face every year, go ahead and start here.You know the drill: Someone got carried away making things “neat” and ran all your mic cables next to the power cables. Or if you didn't have access to a sample of the noise separate from the song? (hint hint) Or if the tone consisted of multiple frequencies? What about if the tone shifted volume throughout the song? Which method would you prefer if the tone shifted frequencies throughout the song? Try to remove this (pure) tone, using either of the methods covered above, enjoy the sweet sounds of Bach's most well-known piece, and then consider the following: The file "Bach.mp3" contains a recording of Bach's First Cello Suite: Prelude (I was going to record my own version, but my neighbor complained)- except that after a couple bars, an irritating, high-pitched tone kicks in. This exercise is going to involve a little more critical thinking. In fact, let's break our signal into two parts and look at the Fourier Transform of each.Ĭongratulations! You just applied Fourier Transforms and filters to real-world applications! If you want, go ahead and try recording your voice and removing background noise from it, then proceed to part 2 when you are ready! Third, notice that just after the 3-second mark, our A440Hz signal cuts off, leaving us with the background noise. While it may appear as though we have harmonics, because there are spikes at other frequencies (such as 110 Hz), we will see in a minute that those frequencies are equally as prevalent in our Pure-Noise sample. An acoustically generated 440Hz signal, such as a key on a Piano, would ring with harmonics of higher and lower frequencies. Second, our pitch has very few harmonics, because it was computer generated. To observe this, notice that the loudest (tallest) peak lies just after 400 Hz (around 440). Let us take a minute to observe a few things here. ![]() This will update the Fourier Graph to show the Fourier Transformation of your entire signal at all selected times. Once you do that, go ahead and select your entire signal (click and drag), then hit Scan Selection in your Frequency Analysis window. If you are following along with Audition, you are going to want to hit Alt + Z to enable your Frequency Analysis window. ![]()
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