The L-18 offers up to 36 dB of limiter gain, limiter knee shape and release controls. The L-18 makes use of the same patented technology found in the McDSP ML4000 multi-band and dynamics processor plug-in, but in an all-analog implementation. A color control provides a subtle high frequency correction before the digital to analog conversion, and can be completely bypassed if desired.
The L-18 Surround Limiter includes support for LCR, LCRS, Quad, 5.0, 5.1, 6.0, 6.1, 7.0, 7.1, 7.0.2, and 7.1.2 formats. A set of channel modes (multi-mono, stereo pairs, front/back groups, or all channels) allow processing of the various surround channels in different groups. LFE processing can be separately disabled if needed. There is even an option for triggering all surround channels from a side chain.
An important aspect of any APB plug-in is that the plug-in is primarily a controller. The APB plug-in takes the input audio signal, combines it with a control signal, and sends both along a Thunderbolt connection to an APB unit for processing. The control signal sets up the analog components to do the selected algorithm with all the parameter values, and the audio signal is converted to the analog domain. The analog version of the audio signal is processed in the analog domain, and then converted back to the digital domain.
By operating the APB hardware from an APB plug-in in this way, all user controllable parameters are recallable and can be saved as presets. Furthermore, because the control signal is married to the input audio signal, parameters can be updating during playback with sample accurate automation.