you can't mute your receiver as that is the source of your test tone. i turned off my amp which sends the test tone to my mains. i'm not sure if it is providing any useful info to me. i've been messing with the slope which came as a default of 24/db and i honestly can't see any change in my freq curve.

what i found handy is to overlay my 990 menu with the sms curve so that i can see changes made thru my 990 immediately on my freq curve of the sms. realized that a 60hz crossover resulted in a smoother freq curve sans the big dips i was getting at a 80hz crossover.

another big help is to write down where you put your slides and their settings as it makes it easy to compare various tweaks you might have done.

a cool feature that isn't included, but i wish was, would be the ability to compare freq curves to determine which one ultimately was better. you can make so many small tweaks that it is easy to lose track of what you had in terms of a freq curve and what you now have. hope that makes sense.