Hi, I have a Korg CA-30 tuner.

The default calibration setting is 440 Hz.

Should I use this setting to tune a bass and a guitar, or are the calibration settings different?

Thanks!

Same. Alternate calibrations are for certain historical or orchestral applications, nothing to do with standard modern tunings for "normal" music.

Thanks, Is 440 Hz the right frequency?

You can use the calibration when you play with an acoustic piano that is off and you got to play with it. Check the piano with the tuner and see how FAR it is off, then you know how far off to tune the bass, guitar and etc.

The simple answer is yes, 440Hz is the correct setting.