I think that would depend on the decoder and sound project installed rather than the controller. Some projects allow you to notch up and down the sound independent of the loco speed. I don’t think it’s seven steps though. In a similar way others allow you to hit a function button which holds the speed (including stationary) while ‘driving’ the sound - which seems like what you are after. I’m not sure if there are any that allow you to hold the sound while changing the speed - although judicious application of a brake function may achieve the desired effect. Anybody else know?
Having said that, many of the more recent, better, sound projects do what you want in a realistic way anyway. I guess you would have try them out before buying them.