[JohnM]

Remember that each RTA band shows the level only within its band, so the higher the RTA resolution the lower the level in each band, whereas the overall level bar shows the level for the full bandwidth of the unit so that one gives you an indication of the noise level, though I don't know the DEQ well enough to say whether that is the input or output level - best check the manual.

 

[JohnM]

I can switch it to display input or output.Would the output level be a better indicator of the noise level?

Depends whether you want to see noise level coming in or going out I guess