I have an Avatar 4x10 (Eminence Delta Pro 10's 4 ohms) and an Avatar 2x10 (same drivers 8 ohms). 2x10 is 700 watts rated and 4x10 is 1400 watt rated. Both cabs are 4 ohm. I know I can expect a 2 ohm load by connecting to the back of an amp with 2 speaker outputs and also the same if I daisy chain the cabs. Both run in parallel. I assume that the 2x10 has 2-8 ohm drivers in parallel to get a 4 ohm load. I also assume the 4x10 has 4-4 ohm drivers (2 pairs in series then parallel together to get 4 ohms) What can I expect to happen if i ran the 2 cabs together with an amp that can handle a 2 ohm load? Would the 2x10 fart out faster or would the whole system add to itself as far as power handling?

You will be sending the speakers in the 2X10 double the amount of power of the speakers in the 4X10. You will be limited by the 2X10, and will only be able to get as loud as just using the 4X10 by itself before the 2X10 farts out.. To mix a 4X10 and a 2X10 properly, you need to have the 2X10 be double the impedance of the 4X10.

The series pairs split voltage. The total input capability would be "1400 watts", beyond that the 210 will suffer.

I doubt Avatar is using custom drivers. Delta 10B is a 16-ohm driver, 4 in parallel is a 4-ohm load. The 210 as an 8-ohm load is the same drivers and wiring. Daisy chaining is a misnomer, as it is a simple parallel connection. Voltage is applied equally to all components of a parallel wiring scheme. Each box will see the same voltage produced by the amp. Power distribution in watts, is different. 410 is 4-ohms, 210 is 8-ohms. Total impedance is 2.66 ohms. Assume an output voltage of 28.3 volts. This is 100 watts into an 8-ohm load, or 200w into a 4-ohm load. The power draw is 300w with both boxes connected, at 28.3 volts. The 410 will be +6dB louder than the 210. The 410 has 2x the cone area, and 2x the power draw.

2x10 can handle only half the wattage as the 4x10. Check. Both cabs receive the same voltage when daisy chained. Check. At the point the 2x10 is making 700w ( fantasy, but this is unimportant in the analysis ) the 4x10 is also making "700w", since they have the same impedance. Check. Beyond "1400" total, the 2x10 is over powered.

The two cabs are different impedance. 2x10 of twice the impedance of the 4x10 is right to get it all matched as a 6x10 of 6 same drivers, and is all happy aside from being less than 4ohm, which upsets many amps. What isn't clear is if the 4 and 8ohms mentioneed are the cab totals or the individual driver totals.

No...the 2x10 is a 4 ohm cab. Delta 10 A is an 8ohm Delta 10 B is 16. I suppose that's what he's using?

Ah...gotcha. 1400 both cabs combined. Total system. So basically, a system is hindered by it's weakest cabinet?

You got it. The only advantages are a slight increase in total sensitivity and getting speakers up into your ears.

... which in almost every case, STRONGLY supports the idea that a '4 ohm' 210 (or 112, 110 etc) type cab is NOT a good idea ... 8 ohm impedance small cabs leave a lot more options down the road ...

After buying this cabinet (I got it cheap, though)....I agree. Lesson Learned. I will add that the Avatar 4x10 - 4 ohm I have is a badass cab. It's never let me down for small/medium club gigs. Handled lots of abuse and sounds good to boot and relatively cheap! I would recommend these for most players. 5 stringers...maybe not? I don't play 5, but I'm tuned to drop C on a 4 and it doesn't give the extreme low impact on the low string like my Ampeg hlf does. 2- 8ohm versions of the Avatar 4x10 would be cheap, killer loud, transportable, and flexible for big or smaller gigs.