@MZKM @pierre @Maiky76 FYI, my consistency checks on the various CTA2034 spatial averages reveal that, aside from previously known issues, the average curves in
@amirm's zipfiles are accurate to around ±0.001 dB, with the largest error (across all published data thus far) on the Floor Reflection of PreSonus Eris E5 XT at 17753.2 Hz, where "Vertical Reflections.txt" says 105.163 dB, but I find 105.1639 dB. It's accurate down to rounding error, basically.
There are some interesting subtleties with the Sound Power calculation. At first I did the following (for each frequency point):
- Convert from dB to Pascals
- Square
- Multiply by the weights in CTA-2034A Appendix C
- Sum
- Square root
- Convert from Pascals back to dB
Even getting to that point was a bit tricky, because it wasn't entirely clear when to multiply by the weights (before or after squaring?) and of course there's the subtle trap of counting 0° and 180° twice (since they appear on both planes).
However, I was a bit confused because, with the above calculation, I would sometimes get discrepancies with the data in CEA2034.txt that, while still very small, couldn't be explained by rounding error alone. For example, on PreSonus Eris E5 XT at 4594.48 Hz, CEA2034.txt says 100.895 dB, but I find 100.879 dB - a ~0.016 dB difference.
It turns out the reason is because the 70 weights, when copied from CTA-2034A Appendix C,
almost add up to 1, but not exactly. They add up to ~0.996. Guess what -0.016 dB corresponds to as a power factor? 0.996. Mmm…
So I added an additional step between #4 and #5 where I divide by the sum of the weights - in other words I scaled the weights so their sum is normalized to 1. That did the trick and we're back to an error within ±0.001 dB. So whatever mistake the authors of CTA-2034A made, at least Klippel, to their credit, didn't fall for that one!