To change the settings on the non-nav radio, hit the button directly under the volume knob with a music note symbol on it - it will cycle through bass, treble, balance, fade, etc.. then finally get to DSP and will show which DSP profile it's currently set to. Once there, hit the +/- keys on either side of that music note button to cycle through the available options. That's all the control you get without nav - no graphic equalizer for instance.
