6
20.
COMPRESSOR THRESHOLD:
A compressor is a circuit that reduces (or compresses) the dynamic range of
the input signal. A great change in volume is shrunk to a more manageable one. This particular adjustment sets
the point that this compression action begins. Any signal above this threshold will be compressed by the amount
set by the ratio control. If it drops below this point, the compressor has no effect. At the maximum threshold
setting, the compressor will be out of circuit for all signals except very high peaks. At the minimum setting, the
source will be almost continuously compressed. The attack and release times are optimized for vocal
applications and are program dependent.
21.
COMPRESSOR RATIO:
The action of the compressor is determined by the compression ratio, which is the
ratio of the input level to the output level. A ratio of 3:1 signifies that the input level has increased three times as
fast as the output (the dynamic range is compressed by a factor of three). If the ratio is 1:1, the output exactly
tracks the input, and there is no compression. Ratios of 2:1 to 4:1 are typically used for vocals and musical
instruments. Higher ratios provide a soft limiting function, since the compressor uses a soft knee design with a
more gentle transition than the expander or limiter.
22.
LIMITER THRESHOLD:
The limiter is an infinite ratio compressor. The threshold control defines the point that
absolute limiting begins. The limit LED will light when this threshold has been exceeded. To disable limiting, set
this control to maximum. The attack and release values are preset.
23.
COMPRESSOR GAIN:
Adjusts the post-processing gain to make up for compression loss. It does not change
the input level to the dynamic’s section. After the ratio and threshold controls have been set, adjust this for a
0 dB average indication on the output meters with the main level control centered and the blend turned fully
CW (wet).
24.
MAIN LEVEL:
The master output level control of the IPro Two
™
. The center position is unity gain, with as
much as 10 dB gain available.
25.
ENHANCE LEVEL:
The SmarTube
™
Enhance circuitry generates pleasing high frequency harmonics from the
source signal. Using our SmarTube technology, we have designed it to give a “tube” brightness to the source
that was not in the original material. It will add crispness to vocals, or add clarity to a dull recording. Start with
the control centered and tune the frequency to where it sounds good. Then adjust the level to add the extra
sheen. It works well in recovering highs that get squashed in the compression process. Be careful of adding too
much! It can get unpleasant if used in excess!
26.
ENHANCE FREQUENCY:
This is the tuning adjustment for the SmarTube Enhance effect. It can be set to
generate second order harmonics from the source range of 2 kHz to 10 kHz (4 kHz to 20 kHz harmonics). For
most uses, this control will be set near the center of its rotation.
27.
BLEND:
Pans between the “dry” pre-amp signal and the fully processed “wet” signal. When set fully CW, the
output will be 100% processed, with all functions on line. At the CCW position, only the pre-amp signal will be
present. Any in between settings will be a blend of these extremes. This control will allow the IPro Two to be
used as a single band of a multi-band compressor. To fatten an input, set the processes to boost the bass, set a
high compression ratio and a moderate compression threshold, and then blend it back into the dry signal. Many
specialized functions are possible.
28.
HEADPHONE:
The headphone level control picks up the main left and right signals before the main level
control so that an independent setting is possible. The headphone jack is a standard TRS 1/4" stereo jack.
29.
TRACK LEVEL:
An alternate stereo input is provided on the rear panel to monitor a sync/cue track, a
computer soundcard output, or other source. This control sets the level sent to the headphones, and is
completely independent of the headphone level control. The track signal is not sent to the main outputs.
30.
GAIN REDUCTION METER:
A twelve segment LED array that tells how much gain reduction is being applied to
the signal. It is very useful for making adjustments, since the action of the expander, compressor, and limiter
controls is easily seen. If there is no activity, the signal’s amplitude is unchanged. Since the left and right
channels are linked with true RMS summing, the same gain reduction is applied to both.
31.
OUTPUT LEVEL METER SELECTOR:
The output meter can monitor either the output signal (default) or the
output of the pre-amp. It is used to set the optimum (0 dBu) internal level and to show the amplitude that is sent
to the output jacks.
32.
OUTPUT LEVEL METER:
This is a peak indicating meter that indicates the level of the signal picked by the
meter selector switch. The 0 dB point corresponds to 0 dBu for the 1/4" jacks and +4 dBu for the XLR output
jacks.
