Absolutely I can, mate!
I work for a company providing digital sound and communications systems for use in Level D flight sims... the sound level varies depending on the aircraft operating state (yeah, that's obvious...
), so you name it!
The Boeing simulation data package includes octave band SPL levels for many operating conditions, with the 63Hz band generally being the loudest... for example the peak level at 63Hz for an on-ground engine acceleration from idle to take-off power is about 90dB SPL, during take-off the peak (again 63Hz band) is around 98dB, while in cruise (FL350, 0.78M) the level drops to about 80dB SPL, while application of full thrust reverse gets you to just about 100dB SPL in the 63Hz band.
The 63Hz band is a good guide for the overall SPL, since the overall sound level is the integral of all energy in the audible range (and recognizing the energy at low frequency is much great than at higher frequencies).
Cheers, GY