Typically, in a home situation we suggest a speaker selector with standard volume controls. That’s because you can turn off areas that you wouldn’t normally use. Those areas truly get taken out of the circuit and in doing so; the other areas get more power and better sound.
In an application that you would have all the areas on most all the time, you could (and should) use just impedance matching volume controls only. When you turn down an impedance matching volume control to its “off” position, it’s not truly off on the back side of the circuit. It has to remain in the circuit or else the circuit would always be changing the load to the amp, therefore causing volume fluctuations everywhere anytime someone even makes one click of an adjustment.
So you can do it both ways. The downside to using the speaker selector method is that it costs a few more bucks.
Everything I read indicates I need to connect my receiver to an impedance matching speaker selector, from there to each room’s volume control and speaker pair. If I have impedance matching volume controls in each room, why do I need a speaker selector? What does the speaker selector actually do? Can I run parallel to each room’s volume control directly from the receiver without a speaker selector? Thanks.