Silent switching for XLR audio switcher

[Smeltis]

Hello everyone,

This is my first post, I really enjoy the site. I'm new to the world of audio electronics and I'd like to build a stereo XLR audio switcher for a studio application as a school project. It will be used to feed the powered audio monitors in a studio I'm building in a few months. I'm designing the box to be passive in the audio path using relays. I have much of the electronics worked out, but I'm unsure how to create silent switching when the audio source is selected. I need the audio signal to sort of ramp-up (quickly) so there's no speaker pop. Can I do this with a capacitor without filtering any of the signals? Does anyone have any suggestions of how I can accomplish this keeping a full range audio signal and passive components?

Thank you for your time,
Eric