Besides the equalizer, the Compressor Expander Dynamics Section is the most important processing unit of the IO5-D/c inline module. The unit offers full control of all parameter. A very effective expander can avoid noise in breaks. A well designed Autogain processor automatically readjusts the make up gain. The control ranges of all controls make it possible to adapt the tonal behaviour from a very soft compression to hard brick-wall operation.

Inline Module 5MT Series D

Compressor Expander Dynamics Section

The Dynamic's Module of the IO5-D/c Inline Module has been optimized for almost 10 years. Compressors like this are widely used in music production consoles and broadcast live production systems as well. The module is optimized not for a special sound but for a wide range of possible settings that allow to adapt the behaviour of the compressor perfectly to the program material and the requirements. Very wide control ranges for all parameters including the attack time make it possible to use the unit as a very fast brick-wall type limiter as well as an ultra soft compressor that can increase the volume of the program but leaves the transients unchanged.

The Compressor has 4 controls; the Threshold ranges from -30 dB to +12 dB, the Ratio from 1:1, which means that the compressor in off, to LIM, which means limiter operation with a ratio of about 20:1. The time controls are Attack and Release. The Release time can be adjusted from 0.1 to 5 sec. With very fast release settings it is possible to make the release inaudible, however, distortion can be high with low frequency program. The control range is expanded in the range around 0.3 seconds what makes it easy to find an appropriate compromise between fast release and distortion.

One, if not THE, most important control of a compressor is the attack time. A huge control range of the attack time offers the choice to modify the operation of the compressor very easy. Of course, it must be possible to operate the unit as a fast limiter, which is possible when the attack pot is all to the left, however, the sound and the tonal behaviour of the compressor changes a lot if the attack time becomes longer. With very long times, it is possible to leave the transients almost unchanged, while the signal is regulated. In combination with a threshold setting that is rather low and a ratio setting in the range of 1.5 to 3, is is possible to gain just volume, without loosing transients and the 'natural' impression of the sound. It sounds just louder while the peak level remains low. This mode is mostly used in many channels at a time and the result is a natural sounding, very loud mix. The attack time range reaches up to 20 ms. A wide varity of settings is possible.

The purpose of the Expander is primarily the surpression of noise in breaks, when the compressor is inactive and the make up gain drives up the noise. There is a threshold control with the range from -60 dB to -20 dB for the expander. The ratio is fixed; it increases exponentially below the threshold. This character offers best results in noise surpression without unwanted side effects. The attack time is always fast while the release time in the the range of 0.3 s. In addition the release time is modulated by the character of the program material. The EXP swich activates the expander.

The Autogain circuit is an analog computer, that calculates the necessary make up gain for a constant output level. The settings of the threshold, the ratio AND the attack time are used for this calculation. The accuracy of the circuit is in the range of 0.5 to 1 dB. Since the Autgain takes care of the make up gain, no additional gain control is necessary. In addition.

The Link Switches activates the console's internal link bus to couple several compressors. Actually, the side chain input signals are coupled. The settings of the particular compressor section are still active, however, the control signal is common for all linked devices.

A LED chain with 5 LED's and a range of 20 dB displays the gain reduction of the compressor and the expander as well.

DYN inserts the entire unit into the signal chain.