600 Series bass plug

[Wilfred]

From the graph in the manual, it leds me to believe that when I plug the bass port, the speaker respond will go lower with a lower output. In HSU term, Max Extention mode.

Is it true? Any one runs their 600s plugged?

[DrBoom]

What happens is that you transform a bass-reflex speaker into a closed-box speaker.
BR cabinets have a lower - 3 dB point, but have a more steep roll-off afterwards.
BR rolls off at 12 dB/octave, closed box rolls off at 6 dB/octave.
In practice, this means that with the ports plugged, the output will be a bit lower, but the roll-off won't be as steep below the - 3 dB point.
So it can go lower, but less loud.