The out-of-phase/in mono/facing each other/closely situated trick works very well. Be certain the system is set to mono(or use track 6 of the following CD), or you're cancelling a smaller percentage of the sound. The Ayre CD, 'Irrational, But Efficacious!' has a "brown noise" track that works very well for break-in of speakers. Brown noise contains energy in the whole audio spectrum, but it's distributed more closely to that of actual music than pink or white noise. (http://www.musicdirect.com/product/73160) This CD also contains pink and white noise tracks. When I burn-in cables, caps, etc: I run all the noise tracks, programmed to repeat, for a few days.
