Noise levels Cockpit and Cabin

[Interflug]

Noise levels are a major factor for the stress level created at any work place.

I'm looking for reliable data about noise levels inside of today's A/C during cruise. Let's say measured at the position of the pilot's head and another measurement in the last row of the cabin. Since noise measurements are tricky to compare, because the level is inverted proportionally to the distance to the emission source and also different weighting curves (A, C etc.) are used, it is tricky or impossible to compare even the little published data that is available.

Is there an industry norm out there how SPL measurements must be taken, that the A/C manufacturers have to comply with when publishing noise level data?

Have any of you internal data, that could be of interest here?

Thank you.