Partial cancellation of out of phase speakers

[midrange]

This is very much a theoretical question and assumes a perfect simple set up. It is not a real world question, so please do not point out the real world problems.

If one has 2 out of phase speakers facing each other with big baffles, drivers not near the edge but opposite each other and minimal separation. I believe the resultant output is zero.

Now my question is if one speaker is producing 90dB and the other is 86dB what is the resultant output?

 

[Twellmann]

Subtract two sources

10xlog10(10^(90/10)-10^(86/10)) = 87.8dB

 

[phase_accurate]

My guess is 81.34 dB.

20*log(10^(90/20)-10^(86/20)) = 81.34

Regards

Charles

 

[newvirus2008]

Yes, the intensity of 86dB is less than half that of 90dB. The result would be better if they're within a dB of each other.

 

[GM]

Post #2 if coherent [identical signal] or post #1 if incoherent. 😉

 

[midrange]

Thank you.

 

[GM]

You're welcome, except I meant post #3, #2. 🙁