The SLC19 from Rolls is a passive, stereo level control, designed to attenuate audio signal levels. Since the unit is passive, it can be used anywhere in a line level signal path, and won't change the audio quality of the source, as can happen with active electronics. The unit provides balanced XLR and 1/4" inputs and outputs, controls volume via a single rotary control and also provides an overall muting switch.
Applications for the SLC19 include controlling the outputs of keyboards, microphone preamps, audio levels from mixers to powered speakers, computers to desktop speakers and much more. The unit can also be used to attenuate high-output levels from certain condenser microphones, since the SLC19 maintains balanced operation, while passing through phantom power.
Passive, line level control with multiple applications
Placed before analog-to-digital converters for instance, the SLC19 can control the input level to the converters, thus preventing clipping
Can be used at the output of one piece of equipment to prevent overload on the next signal device, such as a hot microphone preamp output into a sensitive compressor input
Level control and mute switch for a pair of powered monitors
Passive line level control for extension speakers
Can be used for a high-output condenser microphone to tame its output, while still being able to receive passed-through phantom power