Scratch Scope and Scratch Meter

The scratch scope allows monitoring and reproducable set-up for the declick and decrackle parameters controlling the activity of the DeScratcher PlugIn algorithms. The vertical axis of the display is scaled in clicks (red) or crackles (green) removed from the input signal per time unit. The scratch scope shows the last 12 seconds of the DeScratcher activities. The current click and crackle level is displayed on the right side and conveyed to the left side of the scratch scope display.

In general, you will find that the click level (red) rises from the bottom only if significant clicks are present in the input signal. For records in good condition with the correct setting of the declick parameter, the red line should normally stay in the bottom half of the scratch scope.

The green line, indicating the crackle level, is usually more sensitive to the setting of the decrackle parameter. Even for audio material without any crackles, there will be a significant decrackle level displayed in the scratch scope if the setting of the decrackle parameter is above 80. In this case, the output signal is a smoothed version of the input signal and there may be some loss in high frequencies.

For very bad audio material with a high crackle level, it may be necessary to use a parameter set-up corresponding to the green crackle level reaching the top of the scratch scope display.

If you have problems correctly interpreting the levels displayed in the scratch scope, always ask your ears. For further advice about correct using of the DeScratcher PlugIn look at Application Tips.

The scratch level meter offers an at-a-glance option for evaluating the overall click and crackle level. The more clicks and crackles detected, the higher the scratch level displayed.

This meter can help examine the influence of the declicking and the decrackling function on the audio material being processed. For higher settings of the declick and decrackle parameter, or wrong setup of shape, click sense, and crackle sense, the scratch level meter may display removal activities, even when working on audio material without any noticeable clicks and/or crackles. This is due to the exaggerated, material non-adequate algorithm sensitivity set up. These high sensitivity levels blur the distinction between scratches and attack regions of the original audio signal. Nevertheless, high settings are sometimes useful for heavily damaged audio material. However, it is up to you to find the proper compromise between the level of disturbances and the relative audio quality of the signal after processing.