adt-audio
ToolMod® Pro-Audio Module System
TM222 Stereo Mastering Compressor
3
This pot determines if and how much the density of the mix modulates the release ti-
me. With low density signals (short peaks only), the LT-INT setting causes no changes
while with high density signals (constant high levels) the release time is increased. This
function is similar to the ‚Auto-Release‘ feature of some compressors; however, you
can adjust the amount of ‚autogain‘ instead of switching over to a preset value. All to
the left, LT-Int is disabled. The more to the right, the higher is the influence on the
release time. Please note that the integration time depends on the setting and can be
up to 25 sec. Therefore, it takes some time before the effect of a changed setting is
stable. (You can ‚reset‘ LT-Int just by turning the pot all to the left for a second and
than go back to new setting).
Ratio
The Ratio pot determines the relation between input and output level above threshold
and therefore the magnitude of the compression. With an input level 10 dB above
threshold and a ratio of 2 the output level is 5 dB above threshold. With a ratio setting
of 5, 10 dB above threshold is reduced to 2 dB. All to the left, no compression takes
place. The maximum ratio is 20 : 1. With this setting, the TM222 works as a limiter.
Practical values for mastering are in the range from 1.2 to about 3.
Gain - controls the output level
The gain pot only controls the output level of the compressor. It does not change the
compression itself. The control range is
±
20 dB. The 0 dB position has a center click
and is internally calibrated.
Autogain - automatic compensation of the gain reduction
The autogain circuitry keeps the output level constant independent of the THR, Ratio,
and Attack setting. With autogain you don‘t need to readjust the output gain after a set-
ting has been changed. The AUOGAIN-OFF switch disables the function. The reference
level for the compensation can be internally adjusted. The factory standard setting is
+ 6 dBu ~ + 4 dBV. You can specify other levels with the order. Autogain and gain ope-
rate independently. You can manually change the gain if autogain is active or not.
ENV - Envelope, improves low frequency compression performance
Compressing bass signals with short, pump-free release time settings, can cause dis-
tortion due to the regulation within the period time of the bass signal. With short re-
lease times, the ripple rejection of the control voltage that actually is the rectified
audio signal is low. The ripple on the control voltage causes an additional modulation
of the audio signal that results in distortion. This physical effect limits the minimum
pump free release time related to the gain reduction and the spectral density of low
frequency signals. The envelope circuit improves the performance of the compressor
by a special filter that reduces the compression of bass signals and increases the re-
lease time with such signal a little.
Knee – determines the transition into the compression around the threshold level
The Knee pot determines the ratio in the transition range above the threshold. All to the
left at 0 dB, there is no transition range at all. As soon as the level exceeds threshold,
it is compressed with the ratio that is determined by the setting of the ratio pot. The
knee range can be set to a maximum of 12 dB. With this setting, the ratio increases
from 1 : 1 over a level range of 12 dB to the setting of the ratio pot. Using such a set-
ting with high ratio values can make higher compression possible or reduce the negati-
