Here are some interesting VLF curves: Sweep length now
1M. (Adjusted in details in Test box)
2-20Hz graph limits. 75dB REW target level. SPL meter reads 80dB(C)
Half the sweeps with and half without the C-weighting box ticked in meter settings.
The more horizontal curves below 6Hz are C-weighting. The Galaxy SPL meter cal file stops at 5Hz.
Amazing consistency above ~6.5Hz!
4 x 15" IB opposed driver manifold. Galaxy 140 meter, Fast, C-weighting, Mid SPL range.
I'll try the REW signal generator next for distortion measurements using the REW SPL function.