Simple way to determine effect of combining cabs?

[Bill Fitzmaurice]

3 hours ago, asingardenof said:

 I've done noise assessments to determine if noise barriers are required adjacent to motorways, but that was relatively simplistic (albeit I'm sure the formulae were developed by some serious boffins at TRL who smoked pipes and suchlike) compared to modern acoustic modelling methods.

That's one of the most basic calculations. Where the barrier is at least one wavelength high sound is reflected back. Where it's less than one wavelength high sound goes over it. One wavelength at 100Hz is about 3.5 meters, so reducing transmission above 100Hz isn't difficult. One wavelength at 50Hz is about 7 meters, so reducing bass is impractical.