Speaker Breakin Period

[ddouglass]

As far as blowing speakers go as long as your speakers are rated for a highter wattage than your amp can put out then you won't blow a speaker. It is usually people who use undersized speakers who have this problem.
If a cone on a new speaker was dry and going to crack, no amount of "break-in" is going to help keep it from cracking. In fact when a speaker cone gets in this condition the only thing that can be done is to replace the speaker.
And yes like you two "old-timers" I have been around audio equipment for a long time, though I am not a musician. I have been a technician for 40+ years.