View attachment 222106
That's the result of applying filters
Measurement looks good and filters seem to be calculated correctly. So, your impressions are that filters made the sound "hollow and lifeless"? That certainly comes as a surprise judging by the graph you posted. Can you post the exact filter values and describe how exactly are you applying the filters? What convolution engine are you using?
Btw, please limit the filter effect up to 400Hz only.