Dialogue Editing

224 DAMAGE REPAIR
Figure 12-10 An FFT display created with soundBlade. 7 This sample shows a
classic North American hum, with peaks at approximately 30, 60, 120, 240 Hz, and
so on. The frequency callout (left) reveals that the 60 Hz fundamental measure
58.91 Hz, indicating that the original analogue recording was at some point
transferred off-speed.
approximate “height” that each harmonic rises above noise fl oor as well as
its “width.” You’ll use the width to calculate the Q for each fi lter and the
height to determine the cut value. (See Figures 12-12 and 12-13.) Write all of
this down or enter it into a spreadsheet (Figure 12-14), which has the advantage
of doing the math for you.
Use a multiband EQ to create a deep-cut fi lter for the fundamental and for
each harmonic (see Figure 12-15). For each fi lter, enter center frequency and
calculate Q (center frequency ÷ bandwidth). If your processor allows you to
control the amount of attenuation, set it to a couple of dBs less than the height
to which each specifi c harmonic rose above the visual noise fl oor on the FFT.
You’ll end up with several deep, narrow fi lters. These aren’t notch fi lters
because they’re not infi nitely deep; rather, they remove only what’s necessary
to reduce the noise back to the level of the existing noise fl oor. This should
effectively eliminate hum, buzz, and rumble. If not, extend the fi lters further
to the right to eliminate harmonics at higher frequencies and recheck the FFT
to make sure you accurately measured the components of the noise.
Click and Crackle Removal Interpolation noise removal tools work in two
steps: identifi cation and interpolation. They fi rst identify telltale noises within
a signal (which have an unnaturally short attack and decay) likely attributed
to surface noise. These noises show little or no acoustic characteristics, so
they’re pretty easy to spot. Once the processor identifi es the click, it removes
7 soundBlade is a trademark of Sonic Studio, LLC.