If I remember the C4 and based on the PIC, it's 8db reduction max. Unlike a compressor with a Ratio, the C4 works with Gain scales...
You can basically do the same thing with a Multiband compressor. Calibrate it to give -8db when a 0db or close to 0db signal is passed. The difference here is the basic C4 characteristic of ARC, Electro and a 0.5 Knee.
kelch-