Aphex Studio Dominator 700 - 2 Functional Description; Multi-Band Processing Vs. Wideband; ALT (Auto Limit Threshold)

2.0 FUNCTIONAL DESCRIPTION
Traditionally, limiters have been designed specifically for
a particular application, or with a mUltitude of interacting
controls that must be adjusted to adapt the unit to a particular
purpose. Because the Studio Dominator circuitry is
"intelligent", only a few basic adjustments are necessary to get
proper results in any application. The user simply sets the
OUTPUT CEILING to the level where peaks must absolutely stop
(such as 100% modulation or just under system overload), and
sets the DRIVE control to obtain the desired amount of limiting.
Some additional controls are provided, but they are mainly for
those who wish to obtain effects from the limiter.
2.1 Multiband vs. Wideband processing
Much of the studio Dominator's high performance is due to a
newly created multiband processing technique that overcomes the
problems previously encountered with both wide- and multi-band
limiting.
One of the main problems of wideband limiting is "spectral
gain intermodulation" or "hole punching", the audible effect of
the more powerful low frequencies, such as a bass drum, causing
the whole program, including the high frequencies, 'to drop
momentarily in level. Wideband limiters also tend to sound dull
for this reason.
Multiband limiting attempts to solve this problem by
splitting the audio into two or more bands, and processing them
separately. But more bands means more parameters to control and
the summing of the separate bands to deal with. For a three
band limiter, the number of controls could easily run to twelve
or more per channel!
The Studio Dominator uses program dependent, II intelligent"
circuits to eliminate all but the most necessary controls. This
dynamic control also tends to make the limiting less audible by
providing the right amount of processing at the right time.
2.2 ALT (Automatic Limit Threshold)
Though free of "hole punching" multiband limiters generally
do not keep the output peak amplitude at a consistent level.
This is due to the varying amount of band energies being added
together together with different amounts of limiting in each
band. Such a characteristic is usually unacceptable (at least
in broadcast applications), so a final clipper is added to chop
down the final level to a reliable amplitude at the expense of
added distortion. Another solution is to add a wideband limiter
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