Project containing different components with audio problems
If you are sincere about clean signals, then implement "local battery" for each module.

The "local battery" requires slightly modifying the common_VDD wiring.

You must modify VDD FOR EACH MODULE by installing 100 microHenry in series, followed by the module in parallel with 100 microfarad.

Of high importance in success with "local battery" is WHERE TO GROUND THE CAPACITOR ---- connect the capacitor Return lead/Ground Lead/(-) lead to the module GND pin. Do not casually connect the capacitor (-) lead to the Power Supply GND. 

For example, if you have 5 "local batteries", then there will be 5 unique physical points where the 5 capacitors are connected to "Ground".

This is because the wiring has about 1 microHenry inductance per meter (approximately; does increase as log(length) ), and the Ground Upset is

V = L * dT/dT

where

1uH and 1 amp changing in 1 microsecond produces

V = 1e-6 * 1amp/1e-6 second = 1 volt of Ground spiking for 1 microsecond.

Learn to use the "local battery" with series inductor and shunt capacitor.

For critical circuits, I very happily use series 1 ohm or 3.3 ohm or 10 ohm resistors, with shunting capacitors of 10UF, for opamp circuits I want to be -80 dB trash floor. The resistor is crucial to reject Switching Regulator trash.

How big can "local batteries" become? For motors and their spikes (perhaps their VFD variable frequency Drive electronics), if you INSIST the system must share a VDD among all modules, I'd use 1uHenry in series and 10,000 uF across the motor electronics. This big cap will draw a large initial charging surge when you first power_up the system. The wiring resistance may be adequate to dampen the LC ringing. You need about Rdamped == sqrt( L / C ) for Q of 2, which is rather well dampened.