Question about DSP and Sidechain Compression in FMOD Mixer

I have this question about how sidechain compression works from FMOD’s mixer as I am slightly confused as I go about mixing in-game.

To explain the situation, we have a music bus that is regularly ducked via specific sound effects busses in the FMOD mixer.

In-game, our busses are controlled via in-game sliders for Music, SFX, and Master.

In-game if I set the SFX slider to 0 with FMOD live connected, which effectively would be -infinity dB from the SFX VCA in FMOD, the strange thing is that it still seems like the music bus is registering a sidechain input to the bus even though no SFX can be heard?

I guess I’m asking a bit of a clarifying question in terms of, what would cause the SFX to still be routed to the sidechain input of the Music busses compressor if all in-game SFX are essentially muted?

Is the sidechain effect (not the sidechain compressor effect, but the sidechain effect to which it is linked) in the signal chain of the SFX bus, and if so, is it to the right or to the left of the SFX bus’ fader?

I ask because a sidechain effect sends a duplicate of the signal at its position in the signal chain, and VCAs apply their adjustment to the signal at the fader’s position, meaning that if the sidechain effect is to the left (“upstream”) of the bus fader, its signal will not be affected by VCA; whereas if the sidechain effect is to the right (“downstream”) of the bus fader, its signal will be affected by the VCA.

Thanks for that Joesph, that is helpful. :slight_smile:

So I did going down this rabbithole discover something else that’s a bit odd -

What you said works completed as intended by putting the Sidechain Effect AFTER the bus volume you mentioned at the top level of the Bus. So in other words… If I add the sidechain at the SFX bus, it works. However, if I do the same procedure in a bus that is nested below the top level SFX bus, then it appears that moving it either before or after the fader in the signal chain doesnt stop it from sending it to the Music compressor even if in-game SFX (connected to the VCA) slider is zeroed out?

See the screenshot here: