Question regarding driving an audio system with a generator (without inverter)
This is not a complete answer but should clarify your terminology:


  We're afraid that the generator could spike and break our equipment that will be connected through a power central 220v that converts triplephase to singlephase.


The box doesn't convert anything. It just makes one phase available on each of the blue sockets simply by wiring.



Figure 1. Three-phase breakout box.







simulate this circuit &ndash; Schematic created using CircuitLab

Figure 2. Breakout box internal wiring. (CircuitLab seems to be struggling with the wire crossings. Connections are marked with dots.)

The breakout box has no active components inside. It just takes 3-phase L1, L2, L3 and N (and Earth) input - note the pins rather than sockets - and "breaks them out" into two more 3-phase sockets (red) and four (two shown) single-phase sockets (blue). I have not shown the circuit breakers on the schematic.