The Rupert Neve Designs Portico 5043 Compressor Limiter Duo (Horizontal Mount) is an analog signal processing device designed for both recording and mixing applications. It can be rackmounted horizontally in an optional Rupert Neve Designs 5221-RM rack-mounting frame. For processing, the device consists of two independent compressor-limiters designated "A" and "B". Each can be used on its own, connected together for stereo operation, or connected sequentially to enable composite compression.
The compressor is used to control the dynamics of an incoming signal. When the amplitude of the incoming signal exceeds the compressor's user-specified threshold, the compressor will reduce the incoming signal according to a user-specified ratio. You can set the threshold between -36 dB to +22 dB and the ratio between 1.1:1 and 40:1. For finer-tuned controls, you can set the compressor to engage the incoming signal at a speed of 20 to 75 mS with the attack knob. You can also set the compressor to disengage a signal between a speed of 100 to 2,500 mS via the release knob. By adjusting the threshold, ratio, attack time, and release time you can compress and enhance the dynamic range of the signal so that the quiet sounds and loud sounds are closer to one another in volume. After compressing a signal, you can also use the Portico's gain knob to attenuate or make the signal louder and punchier overall between a range of -6 dB to 20 dB.
As an added feature, the compressor can also function as a limiter when set to a very high ratio, such as 40:1. If the incoming signal exceeded the threshold by 40 dBU, the outgoing signal would exceed the threshold by only 1 dBU. Using the compressor as a limiter prevents the signal from clipping and protects the rest of the equipment in your signal chain.