Interesting article, but it confirms that ““4 times the power = +6dB…”. But that doesn’t explain how 2 speakers that are muted 6db together play 6db louder.
While reading the article you referred to, I found this video about the Tun audio computer program.
It shows that to get a summed straight curve we must have an attenuation of 6 db at the crossoverpoint when we use Linkwitz Riely and 3 db when we use Butterworth. This leads me to believe that the curve shown for each element doesnt show the sound pressure level (SPL). Because then the math doesn’t add up.
