Adding summary information to your impulse file

If you plan on sharing impulses with other Sound Forge users, we recommend adding summary information and BMP images to your files.

1.Open the impulse file in the software.

2.From the View menu, choose Metadata, and then choose Summary Information from the submenu. The Summary window is displayed.

3.Enter the appropriate information in each box.

Note: If the data you want to edit is not displayed in the window, you can right-click the window, choose Insert from the shortcut menu, and then choose a metadata field from the submenu.

Using the new impulse file

To use your new impulse file, open the Acoustic Mirror dialog and choose it from the Impulse drop-down list as you would any other impulse file. If you performed the previous procedures properly, the custom impulse file should realistically recreate the reverberation characteristics of the electronic device or acoustic space.

Using impulse files in creative ways

Now that you understand the use and creation of impulse files, you may want to begin using the Acoustic Mirror tool in more interesting ways than simply applying an impulse to an audio file. The following sections describe some creative and advanced uses for Acoustic Mirror technology that can contribute to the professionalism of your work.

Processing individual audio elements

Instead of applying an impulse file to an entire song, try applying an impulse to individual elements of the song. Applying an impulse to specific notes, chords, riffs, or phrases can quickly change the dynamics of a song. This technique is possible because the tail of processed audio is automatically mixed with the adjacent unprocessed audio.

Adding realistic stereo to mono recordings

You can give mono recordings realistic stereo characteristics by selecting the Convert mono to stereo check box in the General tab of the Acoustic Mirror dialog when applying the specified impulse file. The stereo image produced using this method is virtually indistinguishable from an actual stereo recording.

If you choose to use the Acoustic Mirror effect for stereo simulation, you may find the output too reverberant. If this is the case, decrease the Apply envelope and limit decay value. Frequently, setting this value to as little as 0.1 seconds provides stereo realism without adding a distracting amount of reverb.

Creating special effects

Processing an audio file using a non-impulse WAV file can produce any number of unexpected and interesting special effects. To demonstrate this concept, create several short (less than 12 seconds) audio files using the FM Synthesis tool and save them as individual WAV files. Now choose any of these files from the Impulse drop-down list and preview the results.

We have included several short files on the Sound Forge application disc to allow you to experiment with this technique. After some experimentation, you should begin to notice a few general rules regarding this use of the tool:

•Impulse files that cover the entire frequency spectrum prevent the output from sounding too filtered.

•Using a frequency sweep as an impulse creates a frequency-dependent delay effect.

•Panning within the impulse causes the stereo image of the output to flutter between channels.

•Using staccato sounds (such as drum hits) creates a variety of echo effects.

USING ACOUSTIC MIRROR AND WAVE HAMMER 223