Noise Reduction Manual

For more information see manually adjusting envelope

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Unformatted text preview: up and down arrows in the lower left-hand corner of the Noiseprint page to move the envelope points up and down the amplitude axis. Clicking the buttons increases or decreases the envelope points by 1 dB. Since any signal that falls under the envelope is treated as noise by the noise reduction algorithm, moving the envelope controls up and down has a strong effect on how much noise (and possibly source signal) is removed. If too many sound artifacts are generated during the process, lowering the envelope points will keep the desired signal from being altered. Moving all of the envelope points up is the same as increasing the Noise bias. Fit size This control determines the number of points used to generate an envelope that matches the current noiseprint. When trying to remove a very narrow-band signal, a large Fit size will allow the Fit function to more closely match the contour of the analyzed noise. The Fit size is limited to a maximum of 2048 points. When using a FFT less then 2048, the FFT size will be the maximum Fit size setting. Fit button Click the button to generate an envelope of the noiseprint that is used for noise reduction. Envelope points are generated 6 dB above the noiseprint when using Average for the noiseprint calculation mode and 1 dB above when using Peak. You can move the points further above or closer to the noiseprint by using the up and down arrows at the bottom lefthand corner of the dialog. The number of envelope points generated is specified by the Fit size control. NOISE REDUCTION CHP. 2 31 Reset button Click the button to reset the envelope points. Noiseprint shortcut menu Right-clicking (or pressing Shift + F10 ) displays a pop-up menu on the noiseprint graph. The following options are available: Menu command Function Zoom Selection Choose Zoom Selection to view a close-up of the selected envelope points. Zoom Out Full Choose Zoom Out Full to view the entire frequency and amplitude range. Grab/Pan (On/Off) Choose Grab/Pan to move through the noiseprint graph by clicking and dragging the mouse vertically or horizontally. This option is only available when you are zoomed in on a selection. Normalize dB Choose Normalize to set the maximum envelope point at the top of the graph. Add Point Choose Add Point to add an envelope point. Reset Selection Choose Select All to select all envelope points. Logarithmic Choose Logarithmic to display the logarithmic frequencies in the noiseprint graph. When Logarithmic is not selected, linear frequencies are displayed. Line Graph Choose Line Graph to display the noiseprint as a single, unfilled line. Bar Graph Choose Bar Graph to display the noiseprint as a series of bars corresponding to the real frequency bins. Filled Graph CHP. 2 Choose Reset Selection to remove the current selection. Select All Choose Filled Graph to display the noiseprint as a filled graph. Note that some Windows display drivers incorrectly fill the graph when using this mode. If this is a problem, use Line Graph or Bar Graph instead. NOISE REDUCTION 32 Noiseprint keyboard shortcuts Navigation Left arrow Right arrow Page Up Page down Home End Scroll left Scroll right Scroll right one screen Scroll left one screen Scroll to beginning of graph Scroll to end of graph Selection Shift+Left arrow Ctrl+Shift+Left arrow Shift+Right arrow Ctrl+Shift+Right arrow Shift+Page Up Shift+Page Down Shift+Home Ctrl+Shift+Home Shift+End Ctrl+Shift+End Ctrl+Tab Ctrl+Shift+Tab Ctrl+A Ctrl+Shift+A Ctrl+Up arrow Ctrl+Down arrow NOISE REDUCTION Select previous envelope points Select multiple previous envelope points Select next envelope points Select multiple next envelope points Select to beginning of screen and scroll down horizontally one screen Select to end of screen and scroll down horizontally one screen Select to beginning of screen Select to beginning of graph Select to the end of screen Select to end of graph Shift selection position to the right Shift selection position to the left Select all envelope points in graph Remove selection Move selection up by 1 dB Move selection down by 1 dB CHP. 2 33 Magnification Up arrow Shift+Up arrow Down arrow Shift+Down arrow Ctrl+Numpad+ Shift+Numpad+ Ctrl+NumpadEsc Ctrl Right-click Double-click CHP. 2 Magnify selection horizontally by two Magnify selection vertically by two Demagnify selection horizontally by two Demagnify selection horizontally by two Zoom selection in full horizontally Zoom selection in full vertically Zoom out fully Cancel any move or magnification operation When the selection rectangle is visible, it toggles between: A. Point selection-selects point in bounding rectangle B. Horizontal magnification C. Vertical magnification D. Horizontal and vertical magnification If selection rectangle is visible, it toggles between selection and magnification operations, or it displays shortcut menu Zoom out fully, when not on envelope point NOISE REDUCTION 34 NOISE REDUCTION CHP. 2 35 CHAPTER 3 Click and Crackle Removal Clicks and pops are often found in older recordings or are the result of bad splice editing. They can be detected visually as sharp glitches i...
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