Digital vol. ctrl, EQ, phase, time, sub > DAC

[dude2010]

How do I in the digital domain do the following on my sidesystem and subwoofer system.

 

Volume ctrl. (without bitcomp.)

x-over 100hz- for sidesystem and timedelay and via I2S ship it off to a DAC.

 

And on subsystem. EQ,phase, timedelay, x-over and into the subwoofers.

 

See pic for schematics