adt-audio
ToolMod® Pro-Audio Module System
TM222 - Stereo Mastering Compressor
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density. Use LT Int carefully to loosen the tight compression. If you add too much LT
Int you prevent the compressor from filling the 'breakdowns' in the signal and you loose
loudness gain. With an appropriate setting you can usually reduce the static release ti-
me (with the release pot) without causing additional low frequency distortion.
ATTENTION - due to the long integration time of up to 25 sec, there is a delay before
the circuit settles to a new setting. Change the setting in small step and wait some se-
conds before you check for the result. You can reset the circuit when you turn the LT
Int pot all the left.
10. Checking the Compression
It is very important that you check the settings by switching on and off permanently
and that you always check if the compressed signal and the uncompressed signal ha-
ve the same levels. Even a level difference of 1 or 2 dB changes the impression of lou-
dness a lot.
11. Autogain
Although Autogain is a very useful feature that keeps the output level constant when
you change the compressor settings, there are some limitations.
An analoge computational circuit calculates the gain reduction from the settings of the
threshold, the ratio, and the attack pots. While autogain works at a very high precision
of the less than 0.5 dB over the full range with fast attack time setting, longer attack
time setting may cause higher deviations. With longer attack times, the output level
depends on the level of the short peaks that pass the compressor without causing re-
gulation. Therefore, the resulting real gain reduction differs from the calculated value
that results from the setting of threshold and ratio. Without an additional dynamic cir-
cuit, it is not possible to calculate the precise gain reduction since it depends on the
randomness of the mix combined with the attack time setting. Such a circuit would
change the entire characteristic, which is not useful.
The autogain circuit in the TM222 compensates the attack time setting by empirically
determined correction values. Depending on the peculiarities of a particular mix the
error might be up to 3 dB over the entire range of the attack pot. However, with the
small differences that are made during the optimization of the setting, the differences
are negligible. If you notice a significant level difference after the initial setting of the
attack pot, just use the gain pot for compensation.
Autogain does not compensate an increase of the level caused by the Fill pot and the
slight differences that can be caused by the different settings of the Crest switch.
Special Features
Some additional features are possible
Exchanging Equalizer and Compressor in ToolMod Mastering-Sets
If the Stereo-Mastering-Compressor TM222 is used in combination with a stereo equa-
lizer TM204, TM205, or the 4-band shelving eq with adjustable steepness TM208, two
additional patch cables and the side chain insert of the compressor can be used to re-
