REW Spectral Density

[vmaharaj]

Hi, I am getting more proficient with REW with each passing day and it throws up more questions.

Waterfall - Initial Measure (no filter)


Spectral Decay - Initial Measure (no filter)


If I understand JohnM correctly, one has to also make sure that the filters specified must also get rid of spots like the 30Hz area of my graph. I suppose that this is the "ringing" that people complain about. Do you clean this area up by cutting the output here? I have certainly made improvements in the 60Hz and 90Hz areas. The 30Hz and 42Hz areas are proving more problematic...

Regards, Vic

[brucek]

one has to also make sure that the filters specified must also get rid of spots like the 30Hz area of my graph. I suppose that this is the "ringing" that people complain about. Do you clean this area up by cutting the output here?

Correct. The closer your filters are to matching the center frequency and bandwidth of the modal peak, the better you will reduce the ringing out.

I prefer Waterfall over the Spectral decay. They are basically identical, except Waterfall offers the third Z plane to give you 3D view (shut off Z-plane and match time range and slice, and the two graphs are identical). What I like about the Waterfall is that it allows the overlay capability so you can compare before and after. Quite handy.

brucek