The way for an acoustic concert is to have an appropriately “quiet” drum set and adapt the music to it. Something like a caja drum if the music style allows is ideal (it’s amazing how versatile a well played caja can be).

Failing that, a very dampened drum kit. I know there are practice cymbals designed to be quieter while still providing a good tone. There’s dampeners for drums and I’m sure there must be out of the box quiet drums too.

Then go with a full acoustic bass and a classic guitar. I’ve seen both the caja setup and the heavily dampened drums and both work well.

Upright basses are obnoxious to move but are really the only option if you have to play without amplification. As others have said you’re better off seeing if you can get away with a little amp but if not an upright may be you’re only option.

That being said they’re pretty neat. I’ve only used mine live a handful if times but its fun to play and I think it connects you to your bass playing roots

Don’t buy a nice one to start out. Just get some trashy one until you know if you like it or not

I’d recommend calling the appropriate city department for the rules on noise and playing music in your local park. Most cities/towns have some form of parks and rec department that exists specifically to answer these questions.

Double bass is not remotely the same instrument as bass guitar. If you don’t already know how to play it, you’re in for a long, steep learning curve.

@weastie I’ve used my Kingman out & about before. It wasn’t super loud but it had a decent volume to it. I could hear myself & that’s all I needed.

“Acoustic” basses don’t have a big enough body to produce the volume needed for a bit show. It’s, unfortunately, just a physics problem. You need either an amplifier or a double bass. Do note that, as mentioned, a double bass is not the same as a bass guitar and will have to be learned.