RT60 problem

[Arek Strefa Ciszy]

Hi. I have a room (all walls are concrete) where there is a lot of echo. I want to turn it into a home theater and start by taking measurements and monitoring progress. I’m measuring RT60, but it’s not capturing the full spectrum. It looks strange. Can you help me? Maybe I’m doing something wrong? The graph looks like this:
Thanks a lot

 

[John Mulcahy]

Looks like in its bare state the decay times are very long so you will need to change the IR truncation setting in the Analysis preferences to retain more of the IR, 4.4s should be sufficient.