Having the NGX at FL370 , I decided to close both bleed valves to simulate cabin pressure loss. I was expecting a very quick drop in pressure, and was suprised to see pressure loss was minimal. Opening the outflow valve manually to 100%, increased the rate of pressure loss. Just wondering, does anyone know that this is the way the real aircraft would respond.---This is my first post (hope it got to the correct area !). T/Y