Yeah, it may be OK to 5Hz. You would have to look at the impulse response to be sure and check where the signal is dropping into the noise.I guess it really does not matter but am I flat to 5Hz or am I pushing it to say that?
That depends on the noise level. In the vertical you want to see 0dBFS and then whatever scale is required to properly display the noise. The horizontal also depends on the bandwidth or your measurement.What are the appropriate limits of the graph