Hi Michael_d,
You are correct in being prudent about allowing speakers to reach room temperature before applying power. One thing Ian Colquhoun discovered in doing our temperature testing of the Algonquin outdoor speakers (M3s in a different enclosure) is that in very cold temperatures, the high frequency response totally disappears, because the ferrofluid in the magnetic gap becomes thick in cold temperatures and its viscosity changes dramatically, damping the voice-coil movement and thus ruining the high-frequency response.
The reason I state with some confidence that mechanical break-in does not occur is that if it did, the frequency response of the speaker would change with "break-in". But over several decades of blind listening tests at Canada's National Research Council, we kept a number of speakers, good and bad, as sonic "anchors" which would be rotated in listening tests with other speakers. Those were measured anechoically when new, and also years later, and the frequency responses never changed, nor did the numerical ratings assigned in blind listening tests. In other words, they measured and sounded just the same as when new.
If "break-in" actually took place, then the frequency response of a new speaker would change over time as the elasticity of the surround materials "broke in", and they would sound different. But that did not occur, even after years of use.
Regards,
Alan
