The Mastering Dynamics Processor Dynaround is a multichannel Compressor, Limiter and Expander, that is optimized for the use with 5.1 surround signals. Special controls make it possible to modifiy the control coupling between the front and surround channels. The technique of this analog audio processor is based on the proven designs of the V700 adt-audio Module system. The unit offers many sophisticated features to adapt the dynamic treatment of the unit to the signal.

a versatile Surround Mastering Dynamics Processor

The Dynaround Surround Compressor offers extensive options for the manipulation of 5.1 signals. This analog unit was designed as an multichannel dynamic processor with best sonic performance, that solves the common problem that occur with the dynamic treatment of surround sound.

Surround Mastering Dynamics

Dynaround integrates a sophisticated variable compressor, an expander and a very fast brick-wall limiter. All 3 stages operate indepently. An extensive metering system offers total transparency about the operation of the different stages.

Two common problems are connected with the use of dynamics processors for surround sound signal. Problem no. 1 is, that multichannel, high quality, analog compressors are very rare. To use analog dynamics, very often mono or stereo devices are coupled together or even used in uncoupled mode. If a coupling of several devices is possible, it is a fixed, non variable coupling of all channels almost all the times. For the treatment of surround signals, this way of coupling in not approriate. Though the 3 channels must be strictly coupled as well as the 2 surround channels, it is very often necessary to modify the coupling between the front and the surround channels. Since the surround channels often contain almost only reverb signals and spatial components but no direct signals, the regulation determined by the level of the front channels modifies the spatial impression. In most cases it is approriate to reduce the coupling of the surround channels, to maintain the original 'surround' feeling. Of course, this principle is not valid for the limiter section, that has to force all the channels to the threshold level if necessary. The expander requires a different setting too. In addition, a special problem is always the integration of the LFE channel.

The Realization
For the realization of a 5.1 dynamic processing system, Dynaround offers the following solution. All elements operate independently for the front and surround channels. The adjustments of threshhold and ratio are transferred from the regulation of the front channels to the surround channels. Two additional SHIFT controls can be used to offset the settings of the front channels to the surround channels. With this procedure the front and surround channels can be processed separately and the measure of coupling or offsetting can be determined as needed.

Dynaround has taken this principle further with two additional COUPLE controls. When placed in the center position, front and surround channels operate as independent regulation amplifiers. When turned to the right, a mixing of the control signal of the front channels and surround channel takes place; all to the right, the front control signal is completely coupled to the surround signal. If turned to the left, a mutual interconnection of both rule signals take place. At end position left, the system works as a normal multi channel rule amplifier with even evaluation of all 5 channels. The SHIFT controllers for threshhold and ratio work independently of this feature. All three processors of the DYNAROUND dynamic system operate on this principle.

Compressor Section

The Surround Compressor Section

One of the most starking things about this compressor aside from its excellent sonic performance, is the high degree of control over the very big feature set that is afforded. The THRESHHOLD can be regulated between -30dB and +20dB. Using the SHIFT knob, the threshhold for the surround channels can be offset by ±20dB.

The RATIO is adjustable from 1:1 to 1:20. Also for the advice IO attitude of the surround channels a SHIFT automatic controller with a range from 0 to 2 is present. The ATTACK ranges from 100µs to 30ms, and the RELEASE time can be regulated between 0.1 and 5 seconds.

In addition the compressor has an adjustable, 4-position CREST control, that allows adjustment of the characteristics of the RMS transducers. With this feature it is possible to adjust and regulate the attitude of the compressor as to wether it responds to the peak, RMS or a combination of both values of the signal. In position 1 the peak & hold procedure corresponds to a peak value rectification, and in position 4 an rms conversion occurs. Positions 2 and 3 represent transition stages. The impulse behavior of the compressor can be adapted by this switch to the program. However, it is to be considered that in positions 3 and 4 the fast attack is no longer possible because of the integration already taking place in the RMS transducer. In position 4 the shortest adjustable attack is about 2.5ms.

There is also a variable KNEE control which allows precise control and regulation over the knee characteristics. On position "0" the transition is hard, within approximately 0.5dB. On position 6 the regulation starts 3dB below the Threshhold and approaches the Ratio level with a +3dB adjustment. Thereby a higher compression ratio is possible. The adjustment between the front and Surround channels is the same as with the Expander. The CPLE control sets the regulation of all channels directly and the regulation ratio between the Front and Surround channels. Two 10 elementLED ladders indicate the gain reduction separately for front and Surround channels. The LFE SAVE switch prevents the compressor from processing the LFE channel.

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