Select the data you want to process.
If no data is selected, processing will be applied to the entire file.
From the Effects menu, choose Acoustic Mirror.
Choose a preset from the Name drop-down list to set the processing quality.
Specify the impulse file you want to use:
Type the path to an impulse file in the Impulse box.
Choose an impulse file from the Impulse drop-down list.
Click the Browse button to browse to find the impulse file you would like to use.
Impulse files that have been packaged with the Acoustic Mirror plug-in will have an .sfi extension, but any .wav file can be used to alter the sound file. Choosing a .wav file that is not an impulse can produce interesting effects.
On the General or Envelope tab, drag the Dry Out fader to control the volume of the unprocessed signal mixed into the output from the plug-in. Drag the Wet Out fader to control the volume of the processed signal.
To reproduce the characteristics of the impulse, set the Dry Out fader to -Inf dB, and use the Wet Out fader to set your level. Increase the Dry Out signal to compensate for overly wet impulse responses to enhance clarity.
Use the Response Width slider on the General tab to create simple stereo expansion and stereo collapsing effects.
The default setting of 50 is normal stereo operation. This is the recommended setting to maintain the stereo field of the impulse response. A higher setting will widen the stereo field, but may create an unnatural sound. Lowering this setting will narrow the stereo field. A setting of 0 is essentially mono.
Drag the Response Delay slider on the General tab to control the amount of time, in milliseconds, that will elapse between the dry signal and the processed output. This can create interesting effects and add different dimensions to a reverb impulse.
A positive setting will cause the processed output to follow the dry output. A negative setting will cause the processed output to precede the dry output; i.e. a pre-delay.
Drag the Pan slider to control the balance between the left and right channels in stereo files. A value of 0 indicates center position.
Select this check box and drag the slider to limit the length of the impulse to the specified time. Also, the impulse will be faded according to the Envelope Graph defined on the Envelope tab.
Limiting the length of an impulse file will shorten the decay of the reverberation. Limiting the length also decreases the amount of processing required.
The EQ section offers high and low-shelving filters to tailor the frequency response of the impulse. The cutoff frequency and gain of each filter can be independently adjusted.
To adjust the high frequencies in the processed signal, select the High-shelf start freq. check box and set the start frequency between 8,000 to 10,000 Hz. Drag the gain fader to set the amount of boost or attenuation applied to frequencies above the specified frequency.
To adjust the low frequencies in the processed signal, select the Low-shelf start freq. check box and set the start frequency near 40 Hz. Drag the gain fader to set the amount of boost or attenuation applied to frequencies below the specified frequency.
On the General tab, select the Convert mono to stereo check box. Applying any one of the room environment impulses using the Acoustic Mirror plug-in will make the file almost indiscernible from a true stereo recording.
If the stereo file sounds too reverberant, select the Apply envelope and limit decay to check box and set a low value. A value as short as 0.1 second can add stereo realism without adding reverberation.
Drag the Quality/speed slider to make a trade off between the quality of processing and the speed of processing.
The first thing compromised by lowering this setting is the frequency response of the impulse. This can start to make the processed signal sound dull, and high frequencies will sound unnatural. Using low-quality processing also shortens the length of the impulse.
If you have trouble previewing in real-time, try selecting a lower level of quality. Remember to return this setting to five before processing the file if you do not want the output file to be processed at the lower quality.
Using the Acoustic Mirror Plug-In
The Sound Forge application disc includes impulse files that you can apply to your sound files. You can also use any .wav file that is less than 12 seconds or create your own impulse.
Most impulse files cover the entire frequency spectrum. This prevents the output from sounding too filtered. Using a frequency sweep as an impulse creates a frequency-dependent delay effect. Note also how panning in an impulse causes the stereo image of the output to flutter between channels. To generate echo effects, use staccato sounds such as short drum beats as impulse files.
Try creating sounds using the Sound Forge FM Synthesis tool and then use those files as impulses.
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