Music venues in Nashville, Memphis and Austin

Hello everyone

I'm heading to the US in 4 weeks for a couple of weeks' holiday.  Spending some time in the above cities (inspired by the Dave Grohl / Sonic Highways documentary).

Already booked for Grand Ole Opry in Nashville, and will try to get tickets for Bluebird cafe there also.

Any recommendations for good live music venues in Memphis and Austin?  I'm more of a blues guy than a country guy, but will take the opportunity to immerse myself in some country music while I am there.

Thanks

David