Soft Limit And Push-It - Apogee Mini-Me Owner's Manual

Soft Limit is an analog process that acts as a guard against digital 'overs' that can result from high-level tran-
sients in the incoming audio signal. When enabled, Soft Limit will round out peaks in the incoming signal in order
to eliminate the undesirable effects of clipping the A/D converter chip. This rounding will begin on peaks at
about –4dBFs and gradually smooth them out up to 0dBFs in order to safeguard the audio signal. This process
will not only eliminate digital 'overs', but it will also help to get a few extra dB of gain to tape or disk. See the
illustration below for a visual representation of how this circuit works.
Push-IT is a unique gain control circuit consisting of a compressor and limiter that are integrated with Soft
Limit. All compressors and limiters adjust gain and are controlled by a detection circuit known as a sidechain.
Every sidechain has a certain response time, and as a result it is possible for occasional fast transients to evade
the limiting action. When used with Push-IT's limiter, Soft Limit smoothes out any transients that may slip by the
limiter's response time. You have the ability to chain this limiter with either of the two different Push-IT com-
pression circuits. When used, Push-IT provides significant extra "punch" and gives the user almost total securi-
ty from overloading the digital outputs.
The main differences between the two compression surves are the attack and release times. These parame-
ters are adaptive and adjust according to the characteristics of the signal. Compression curve number one has
much quicker attack and release times. This circuit will lend itself well to percussive instruments, acoustic gui-
tars, and sources with fast attack.
Compression curve number two has slower attack and release times. This circuit is better suited for bass gui-
tar and vocals, which tend to have slower transient peaks.
The graph below illustrates the various compression and limiting curves generated by the combination of
Soft Limit and Push-IT. Soft Limit is engaged by the three-position toggle switch in the upper center of the front
panel. This is labeled "OFF" to the left – neither Soft Limit (SL) nor Soft Limit + Compression (SLC) enabled;
"SL" for the center position – Soft Limit only; and "SLC" to the right – Soft Limit + Compression (SLC) enabled.
In the SLC position, the lower "Curve" switch is used to select curve 1, 2 or 3.
Mini•Me User's Guide

Soft Limit and Push-IT

Page 20
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