How to change octave in Left part?

[Saintade]

SX600 - I'm working on a piece where I have two instruments in the right parts, but I want to play a bass solo guitar in the LEFT region. But it plays the guitar sound only in the middle octave and I want it to play an octave lower. If I click on the octave up/down keys, it adjusts the RIGHT parts ok, but not the LEFT. It's driving me nuts trying to find a way to lower an octave the LEFT part - any ideas anyone?

[Des O]

Looking at the images of the SX600 its pretty much like a genos screen, obviously you may not have this function but have a look.

Menu
Menu 2
Voice setting
you will then see your voice option left& right in the Tune area, select octave.

Hope this helps.