I have been very intrigued with this subject. I made a search and destroy map on Sandbox in the Crypt. On the ground level there are various explosions. It's really neat because it sounds like a war is going on around you, just like COD. Has anyone else heard or done this, if so, please tell me what you did.
I've tried implementing something like this into a map before. Unfortunately, the constant explosions of the Fusion Coils/Vehicles promote chances of lag so it isn't something that is used too often.
I think Cayanne used this. It was either that or Cyrus... I can't remember. I played on both of them though and it never lagged in the one that had the explosions in the background. It sounded really cool too.
Exploding grav lifts arnt that laggy if you want a high pitch bang sound and answer to your question, ive done this, its just that it can lag your map, I wouldnt recommend it. Turrets are also nice. I would only ever use these effects for single player maps like puzzle maps.
Its a really cool effect, best when subtle. Only use a few bangs, or whatever else you plan to implament. Shock used Forklifts on the 2v2 tournaments Urban. They don't sound very loud in Forge but you can hear them well in customs and it sounds like industrial goings on.