- I93 Voice Compressor
- An extensive Dynamics Unit with Limiter, Expander and a special Voice Compressor for 4U frames
- Compressor and limiter of the voice compressor have a lot of additional feature to cover the special needs of the dynamic treatment of vocals. Of course, the unit is not limited for this use.
- The I93 is available with electronically balanced inputs and outputs. The functions of the voice compressor are regulated by several VCA's. The feed forward control action allows extremely fast and accurately linear operation. Limiter, compressor and expander are independent building blocks without mutual influence.
- The limiter is implemented for very fast brick-wall operation. It is able to fade down short peaks of up to 5 dB in an inaudible way. The release time can be regulated from 0.05 s to 5 s and is additionally controlled by the structure of the signal. The attack time ranges from 0.05 ms to 5 ms. The range of the threshold control is from +20 to 9 dB. HISS modifies the gain of a bell filter in the side chain of the limiter. It can be used to increase the high mid range (center frequency 7 kHz) to suppress sibilant components. The range of the control is from + 12 dB to - 2 dB. In the - 2 dB position, the filter affects the sound of the limiter, that, with certain signals, seems to reduce high frequency. The gain reduction display is a LED chain with 5 LED's and a range of 10 dB. A separate switch activates the limiter section.
- The range of the threshold is from -30dB to +15 dB. The range of the Ratio is from 1:1 (compressor inactive) via infinity (limiter operation) to -1.5 (overeasy range). These ranges cover all areas of application of the voice compressor. The release range is from 0.5 s up to 3 seconds. The Attack range is from 0.5 ms up to 30 ms. The gain make-up is handled by a very accurate and switchable auto gain that maintains a constant output level (within a 1dB range) regardless of the settings of the main parameters. In addition, there is a gain control with calibrated center position and a range of ± 18 dB. The compressor has precision RMS converters whose behavior can be adapted by the CREST and ENV switches to the input signal. The KNEE control is continuously variable from 0 dB (hard knee) to 12 dB (very soft knee). In combination with the overeasy range of the ratio control a curved characteristic can be adjusted, that covers a level range of more than 20 dB. The switch CREST determines the reaction of the converter in relation to the peak and/or RMS value of the signal. With this facility, the control characteristic of the audio signal can be highly affected. The switch has 3 possible positions. In position PEAK, the converter operates as peak rectifier. Position RMS switches it into RMS mode. Position MD activates a medium value that is the best choice for many applications. The envelope switch determines the reaction of the compressor section to low frequency signals. Because effective compression with a relevant increase of the loudness of the signal generally depends on a setting of a short release time and medium to long attack. The envelope setting increases the effectiveness of the compression on the low frequency edge of the signal when there is a short release setting that causes the problem of harmonic distortion. The HUE pot controls a filter sectionside chain with a range of ±12 dB. The section has a shelving characteristic with a limit frequency of about 5 kHz. It modifies the mid and high frequency characteristic of the compressor and offers many interesting variations of the final result. The FILL pot adds the uncompressed signal input signal to the output of the compressor. Using very high compression rates, an appropriate setting of this control, which covers the range from off to 6 dB, can fill the negative side effects of the high compression without loosing the pressure. This function does not affect the operation of the limiter that is a total independent building block. This combination of special controls allows using very high compression rates with a lot of loudness gain and gives the choice to adapt the characteristics of the compression to the signal in many ways. A LED chain with 8 LED's and 25 dB range display the gain reduction of the compressor and the expander of the voice compressor.
- The expander is used to suppress disturbances while breaks, when the compressor increases the overall gain of the device and therefore increases the level of any kind of background noise. The control range of the threshold is from -10 dB to 50 dB. A 3 position switch is used to set the attack time. The release control has a variation range from 50 ms to 3 s. The ratio is exponential. The lower the level is, the higher becomes the ratio. This produces a soft fade out that increases its intensity at low levels and results in a very good suppression of any kind of noise. The gain reduction of the expander is displayed on the compressorxs LED chain. A separate switch activates the expander.
- The I93 voice compressor fits into a 4U high INTEGRATOR mounting frame.