The Retouch Tool

The spectral editing mode is a very powerful tool in post processing and audio restoration since many problems can be better isolated in the time frequency domain than using a time range alone. One of the most interesting applications is to attenuate unwanted noise based on information from the surrounding areas in time and frequency. The Retouch tool is a specialized tool for this purpose.

Retouch reduces the magnitudes in the selection based on a reference that you can position freely. Any noise present in the selection that is not present in the reference signal will be attenuated. You can process both horizontally (keeping tonal information) or vertically (keeping time events). Horizontal processing is the most common usage since it preserves tonal information.

The first step of the process is to select the smallest region possible that covers the unwanted noise completely. You can choose whichever selection tool is more suited (see Selections in Time and Frequency). When done activate the retouch tool using the corresponding button in the main toolbar:

Alternatively, you can choose Edit > Active Tool > Retouch Tool to enable or disable the retouch tool. After activation, you can see a process button and a green reference signal indicator as depicted below:

The retouch tool in Acoustica allows you to attenuate unwanted sounds that are isolated in time and frequency. In this example there is a disturbing beep from a camera auto-focus.

You can press Ctrl and move the mouse to position the reference signal indicator. The reference should be a clean signal that is as similar to the wanted signal as possible, either before or after the noise you want to eliminate. You can also processes along the vertical axis by positioning the reference above or below the unwanted noise. When you have positioned the reference signal indicator, click the arrow button to process.

Pressing the Retouch process button will remove the beep as shown below.

The disturbing beep is completely removed after processing with the retouch tool.

Processing Options

You can click the arrow down button on the retouch tool button in the toolbar to change the retouch tool's processing settings:

You can change the Retouch processing mode and strength.

The Attenuate mode will attenuate all signal components that are lower than the reference whereas Replace will use the signal component levels from the reference even if they are higher. You can reduce the strength if you want more gentle processing.