I have asked this question on TB and got conflicting answers based on what the manufactures told me so I will ask you. Looking seriously at an m9 Carbine Mesa head with a 410 and 210 cab. Mostly their cabs are all 8 ohms but you can order 40hms as well. The one at my store is both 8ohms but most people say don't do this because the 210 will be over driven getting the same wattage as the 410 cab. Keep in mind the amp puts out 900 watts at 4ohms so each cab would get 450 watts and the 210 cab is rated for 600 watts, so don't know if that would be a problem or not. Most say get a 410 4ohm cab and have the 210 cab at 8 ohms in order for each speaker to get the same wattage, what do you say ? Thanks in advance.