Complete cancellation would prevent any movement of the coil. However it WOULD heat up VERY rapidly. Without movement and enough power' date=' it will cook. The interesting part is that both coils, in this scenario would be opposing each other, so as they heat up and the glue weakens, the coil will likely grenade sooner from the opposing forces...[/quote']Nice try, but you are off base here. There are no opposing forces. The magnetic fields of the two coils will simply cancel each other out. Result is no force at all. The two coils are wrapped together, they don't sit next to each other. Yes they would heat up and the lack of cone movement would prevent cooling air from circulating, but if you were to turn everything on and nothing happens, hopefully you wuld have enough where-with-all to turn the system off and figure out what is wrong rather than keep running it and heating the coil up.
Also, while partial cancellation may not damage anything over the short term, it WILL reduce your output.
As long as the signal going to the coils is the same, there will be NO cancellation so not a problem. A small amount of cancellation will cause a drop in ouput but will not cause any damage short or long term.
If you are doing this as a daily driver, I suggest that you get the power on each coil as absolutely close as you can get it.
That is not nearly as important ans this:
Also try to make the signals absolutelythe same going into each coil....
Trust me I know this for a fact. I gained 1.7dB last year at a show by level matching my 4 mtx's when I was running those amps...
Likely more a factor of running more power overall by matching to the higher wattage amp than actually eliminating cancellation. I'll say it again, if the signal is the same, there will be NO cancellation within the sub if the power going to each coil is a little off.