The Opti-FET and DE-CL were designed with much wider threshold range than the Dual-Band compressor… -47dBu for the Opti and DE-CL vs -37dBu DB-CL. Also, the ratios for the Opti and DE-CL can go much higher than the Dual-Band, 20:1 vs 7:1.
The Opti-FET was designed so that it could be use as a gentle compressor or have the ability to be a more extreme squish box. The compressor circuit in the DE-CL was taken from the Opti-FET and a specialized limiter circuit was married up with it… that’s why they share similar numbers.
I looked at the settings that I have been using on my Opti-FET. I use it more as a polite compressor with a quick release and the attack pulled back just a bit.
RATIO 9:00
ATTACK 10:00
RELEASE (min) 7:00
I adjust the threshold so that the LED is lit for about half of the time the note is ringing out.
I also use the side-chain EQ with bass pulled back a bit. Turning up/down the EQ controls will modify the threshold level for those frequencies. With me turning down the LOW EQ, I am making the compressor less sensitive to the low frequencies and it allows for more bass energy to pass without working the compressor as much.
LOW 9:00
MID 12:00
HIGH 12:00
I think these setting should get you close to what you are looking for.
-Frank