User`s manual

Equalize Voice or Attack Noise Output Gain specifies the digital

boost to be applied to the entire spectral inverse filter curve. Normally,

Output Gain is applied in the Equalize Voice mode; the gain is usually

0 dB in the Attack Noise mode. This boost is necessary to make up for

the volume reduction performed by the inverse filter. Output Gain

should be initially set to approximately 0 dB. If Output Gain is applied

and the filter output is distorted, reduce Output Gain setting and re-

Build the filter; if filter output level is too low, try increasing the

Output Gain setting.

Lower and Upper

Voice/Noise Limits

For Equalize Voice operation, specifies Lower Voice Limit and

Upper Voice Limit. These are the lower and upper frequency limits

over which the input voice audio is equalized. Audio outside these

limits is rolled off and ultimately attenuated by 40dB. A Lower Limit

above 300 Hz and an Upper Limit below 3000 Hz is not recommended,

as voice intelligibility may suffer.

For Attack Noise operation, specifies Lower Noise Limit and Upper

Noise Limit. These are the lower and upper frequency limits over

which noise in the input audio is attacked. These values should be set

to "bracket" any noise spikes in the original audio power spectrum.

To set the upper and lower frequency limits, use the horizontal scroll

bars to position the two red markers on the Filter Display to the desired

frequency positions. You may also click-and-drag the red markers in

the Filter Display to the desired frequency as well as enter the frequency

amount in the frequency entry fields.

Output Shape Block: Specifies the final reshaping curve to be applied to the entire SIF filter.

For Attack Noise only Flat should be used. For Equalize Voice four

curves are available and include Flat (no reshaping), Voice (6dB/octave

rolloff above and below 500 Hz), and Pink (3dB/octave rolloff above

100 Hz), and Custom. The Voice and Pink curves are provided to

reshape the resultant audio power spectrum to that of a typical voice

spectrum; the Voice curve provides "hard" reshaping, while the Pink

curve provides softer reshaping of the spectrum.

When selecting the Custom option the Edit button will be enabled.

Clicking the Edit button will display the SIF Custom Curve edit

window (Figure 4-40). This window operates exactly the same way

as the Hi-Res Graphic filter. For operation see Section 4.4.13: .