Dialogue Noise Suppression Line up Nov/Dec 2008
96808_P18_20_Noise:FEATURE/TECHNICAL PAGE 23/10/08 09:12 Page 18 Dialogue Noise Suppression TV walls, moving lights, and the fashion for hard reflective set designs has made capturing clean dialogue a serious challenge in modern television. Digital Noise Suppression offers a The CEDAR practical solution as Peter Best DSN10000 dialogue explains. noise suppressor he modern broadcast environment The use of dynamics new, more precise can be a source of many types of processors such as noise gates technology possible: T noise and unwanted sounds. Some and full-spectrum expanders was no spectral subtraction. This of this, such as room ambience and noise better, resulting in unnatural break-up of technique splits the introduced by the re-use of existing noisy the signal or unpleasant noise pumping. spectrum into numerous material, is unavoidable. Others, such as In the 1960s, the multi-band expander bands (typically 512 or 1,024) and uses a those caused by undiagnosed electrical was developed. An early version of this split noise fingerprint to determine whether the faults and poorly positioned equipment the spectrum into four bands and, if the amplitude in each has dropped below the can – with care – be cured at source. But signal level in any band dropped below a threshold below which gain reduction is many noises cannot be eliminated by careful user-defined threshold, the amplitude of applied. Although expansion and spectral microphone positioning, intelligent that band was progressively suppressed subtraction are usually viewed as separate placement of equipment and good according to a simple gain ratio. This technologies, one is merely an extension of maintenance, and it is here that broadcasters technique worked on the assumption that the other, albeit with different operational must turn to signal processing to suppress or, signals with amplitudes above the threshold characteristics and different side effects.
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