Ernie you're pretty much right about those charts. I learned them when we trying to find alternatives to 70v systems in commercial buildings. Mostly, anyway - Parallel cuts impedance in half (8 to 4), series doubles it (8 to 16). Series can work if the speakers are just plain full range drivers.

I discovered that wiring crossovered/capped/multidrivered speakers in series, we got some pretty goofy sound (like just hi frequency tweeter in one room and low base in the other because of the direction of the current). The worthless Sony/Kenwoods have some other wizardry that prevents this little problem.

The Phoenix Gold box really does a fine job and doesn't require a wire nut farm (that series/parallel stuff). You can then give him a warranty and the next installer thru there in about 5 years won't be looking to put your head on a platter.

If he doesn't jump for something like the Sam 100, I would leap for cover before the little blue mushroom cloud says "you're fired".

If you are talking cheap, you probably are not talking about any true "high quality" speakers. So in that case, the frequency response aberrations in mixing speakers would be secondary to the bigger issue of not all rooms playing at the same volume. Now there's the issue.

I love the guys who wanna "save money" and they do the cheappy speaker selectors/ or Impedance VC and the replace one cheap receiver after another as they keep burning themselves out. ahhh- thanks for all the work J&M ;-)