I searched it but i dont have an exact answer. So real channels are affecting the performance as i understand. But what about the virtual ones? It says “Not audible” but what about CPU? what about memory?
FMOD - Settings (virtual channel count)
The documentation says
A Channel can be queried for whether it is virtual with the Channel::isVirtual function. When going virtual, the sound’s time will still be ticked and any fade points will still continue to interpolate. Any additional DSPs attached to the Channel will be preserved. When the Channel becomes real again, it will resume as if it had been playing properly.
Virtual channels have a similar memory overhead to real channels, as a virtual channel’s underlying DSP units and the sample data being played are still present in memory. However, the CPU overhead is significantly lower for virtual channels than it is for real channels. This is because when a channel becomes virtual, the channel’s underlying DSPs become idle - while the DSP clocks continue to increment, the DSPs no longer process and generate an output, which saves on CPU usage. DSP units that have a tail (i.e. reverb, delay) receive no input since their input is idle, and will keep processing until the tail finishes and then become idle.