4.Drag to draw a new waveform section. The new section is integrated into the original waveform, replacing the section containing the glitch.

Repairing audio using Audio Restoration plug-in

Sound Forge software includes an DirectX plug-in (part of the Noise Reduction plug-in) called Audio Restoration that you can use to remove surface noise from old recordings. For more information on this plug-in, see the Sound Forge online help file (accessible from the Help menu by choosing Contents and Index).

Synthesizing audio

You can generate custom tones and waveforms for use in your audio projects.

Generating DTMF/MF tones

You can generate standard dial tones used by telephone companies.

1.From the Insert menu, choose Synthesis, and choose DTMF/MF Tones from the submenu. The DTMF/MF Tones dialog appears. Tip: You can also click the DTMF/MF Tones Synthesis button () on the Insert toolbar.

2.Enter the phone number to be generated in the Dial string edit box, including pause characters.

Note: Unknown characters are ignored.

3.Use the Amplitude fader to set the peak level of the waveform.

4.Select the Tone style to generate radio button corresponding to the tone to be generated.

•DTMF (Dual Tone Multi-Frequency) signals are used by standard push-button telephones and are generated using combinations of 679, 770, 852, 941, 1209, 1336, 1477, and 1633 Hz sine waves.

•MF signals are used internally by the telephone networks and are generated with a combination of 700, 900, 1100, 1300, 1500, and 1700 Hz sine waves.

5.Specify the output length (in seconds) of each tone in the Single tone length box.

6.Specify the length (in seconds) of silence between tones in the Break length box.

7.Specify the pause length (in seconds) to be inserted for a pause character in the Pause length box.

8.Select the Fade the edges of each tone check box to help prevent glitching.

9.Specify the pause character in the Pause character box.

10.Use the Insert new tone sequence at drop-down list to specify where the generated tone is placed in the audio file.

11.Click OK.

156 CHAPTER 9