Break-in procedure

Is there any downside in connecting one speaker out of phase with respect to the other during break-in (i.e., pointed at each other) or, by corollary, is there any directionality issue to consider if one speaker is out of phase with the other? I am also considering purchase of a Conrad-Johnson preamp that inverts phase- so I will need to make an appropriate adjustment in the cabling (my digital source does not have a phase invert feature). Is this an issue considering that the speakers have been running in an opposite (i.e. normal) configuration?
Your pre-amp inverts polarity, not phase. You don't need to consider that, just connect one of the speakers out of phase. Presumably you are putting the speakers face-to-face and running them out of phase in order to cancel out as much of the sound as possible. If so, use a mono source. And be careful not to turn the volume up too high.

Not sure what you mean by directionality.
I would NOT wire one speaker with reverse polarity from the other and then face them at each other to help break them in. This works the one speaker's suspension in the normal manner that it would be used while the other speaker is working exactly the opposite of normal.

Having said that, i would face them together and then play a mono signal into them OR use the out of phase track on the Ayre Acoustics Irrational but Efficacious "break in" cd. Do NOT try to use this track with your preamp in mono mode as it will simply null itself out and you'll have absolutely nothing coming out of your speakers.

As a side note, i used this entire disc to help break-in my father's speakers that we just got done rebuilding. This disc was put on repeat and played for almost two weeks straight. Given that he wasn't home during that period of time made it a lot easier to do this : ) Sean

PS... Be careful with the Ayre disc as it starts out at 5 Hz on two different tracks. Vented speakers will be throwing like mad if you have the volume turned up at all, resulting in possible damage.
What difference would it make to work one speaker in the "normal" manner and one reversed during a break in? Range of motion is the same, and the speakers will see reversed polarity source material all the time anyway. If it's really a concern, reverse polarity between channels half way through the break in process.
Drubin: Some drivers do not have the same excursion capacity in both directions. It is therefore possible to increase the potential for a driver bottoming out when running it in reverse polarity. Due to the initial thrust, which would normally be forward but is now backward, and the inertia involved in trying to stop the cone, overshoot into the back plate becomes more of a possibility. The end result would be damaging the voice coil former and possible dragging of the cone and the resultant poorer sonics / overheating. Couple this with the fact that some people stand on the throttle trying to break the drivers in faster and you could end up worse than if you just let them "play in" gradually.

Like anything else, a product should be "broken in" in a fashion that simulates normal use. Otherwise, the "wear pattern" will not be the same as what it undergoes in normal use. Using a special disc for this purpose is therefore preferred to using the speakers in a non-standard fashion. Sean
If half of all records have polarity reversed, as many claim, how can this not be "normal use"?
Sean...This idea is out to lunch! That's ok, because most of your comments make sense.