@kijanki OK. I see what you are saying. What it comes down to is that we have been interpreting the Benchmark statement differently. And both interpretations are reasonable, IMO, as long as each interpretation is properly understood and applied.
You are interpreting their statement such that:
In case on hand each speaker sensitivity is 86dB. Two of them playing at the same time add +3dB, room adds +3dB and distance of 2m causes 6dB drop resulting in 86dB sound level at listening position when 2.83V is applied to both speakers.
I agree with this statement, but I have been interpreting Benchmark’s statement differently, with my interpretation having been indicated at the end of my previous post. As I say, though, I think neither interpretation of Benchmark’s statement (yours and mine) is unreasonable.
In any event, though, the 101.7 db and 107.7 db numbers I originally stated in my response to the OP do in fact reflect the presence of two speakers.
Best regards,
-- Al