Increase the DirectX buffering size

1.Open the Acoustic Mirror dialog.

2.Right-click an empty area of the dialog outside of the four tabs and choose Configuration from the shortcut menu. The Real-Time Preview Configuration dialog is displayed.

3.Reconfigure the Buffers to process per second and Total playback buffers controls. Typically, lowering the Buffers to process per second value and increasing the Total playback buffers value reduces gapping during real-time previewing.

Close all memory-intensive applications

Real-time previewing may be limited by any additional applications operating on the desktop. To avoid this situation, close all memory- intensive applications prior to using this effect.

Add additional RAM to the system

We require at least 512 MB of RAM to operate Sound Forge software and its related tools.

Add a faster floating point arithmetic processor

Many high-speed processors are still lacking in speed when processing floating point arithmetic. We recommend using high-speed processors that provide exceptional floating point arithmetic for reliable real-time previewing.

Impulses do not recover properly

If you experience problems recovering custom impulse recordings, verify each of the following:

1.Verify that you have trimmed the recorded test tone based on the mode chosen from the Impulse recovery mode drop-down list. For more information, see Trimming the test tone on page 221.

2.Verify that the second spike is present in the recorded test tone if the Auto-detect timing spikes options is specified.

3.Verify that the file specified in the Test file used box is the exact test tone used to make to field recording and that neither its length or data has been changed.

4.If the impulse still does not recover properly in Auto-detect timing spikes mode, normalize the spikes in the recorded test tone file. This should aid the auto-detect algorithm in detecting the timing spikes and recovering the impulse.

Recovered impulse is too noisy

To maximize the impulse’s signal-to-noise ratio, you should verify that the field recording’s noise floor is not too high. When recording in noisy environments, increase the test tone’s amplitude until the test tone is at least 25 dB louder than the noise floor. At least 40 dB of signal-to-noise is recommended for optimal impulses. If you cannot avoid noise when recording in the field, the Noise Reduction tool can salvage a session.

Speaker nonlinear distortion can also cause noisy impulses. The most common source of nonlinear distortion is loudspeaker harmonics. Most speakers display substantial harmonic distortion at low frequencies. For example, when you play a 60 Hz tone, the speaker vibrates at 60 Hz, but also outputs lower-level audio at multiples of 60 Hz (120, 180, etc.). The impulse recovery method greatly minimizes these low-frequency distortions; however, inexpensive tweeters often display substantial high-frequency distortion that can disrupt the recovery process. When possible, use high-quality components and do not overdrive the speakers.

Error message explanations

The following sections briefly describe Acoustic Mirror error messages that you may encounter.

The selected file is not a valid test file

The file specified in the Test file used box is not a test tone file included on the Sound Forge application disc.

USING ACOUSTIC MIRROR AND WAVE HAMMER 225