Apologies, as I neglected to approve the attachment at the same time as the post.
What do you find unusual about the frequency analysis?
It's been a while since I've recorded loud, amplified rock-type music and done a frequency analysis on my live recordings, but my vague recollection is that I commonly had a stronger response in lower frequencies v. higher frequencies.
Also, keep in mind it looks like the frequency analysis plot is showing frequency in a logarithmic view. Try toggling to a linear view and see if it more closely aligns with your expectations.