my subs are nippy

[eflb55]

I live in Michigan so it gets pretty cold here in the winter. Lately in the mornings and on cold days my subs don't use their full potential until maybe 20 minutes after using them. A friend of mine told me that the voice coils do not move as well when they are cold so just put the bass on high and let them warm up. Is there anything I can do to warm them up faster? I guess I could get a starter adn have them play in my driveway in the morning but that doesn't my neighbors wont appreciate that. Any help would be just peachy thanks.