impedance selector switch? huh?

This is actually a home audio question, but you guys are the most knowledgeable people I know when it comes to this kind of question, so I figure it can't hurt to ask here. I have a 22-year-old Kenwood KR-V6020 stereo receiver. It has two pairs of outputs, which I use to drive a pair of 6 ohm speakers and a pair of 8 ohm speakers. What I find odd about it is that it has an impedance selector switch with two options: 4 ohm and "8 ohm or more". What confuses me about this switch is that I thought impedance was determined by the speakers ohm rating and how you wired them (series v. parallel). So what is this switch doing and where do I set it? How about if I was just driving the 6 ohm speakers? I can't find a manual for this antique anywhere.

Those switches invoke current limiters to protect the amplifier from overload when used with a lower impedance load.  With 6-ohm speakers leave it in the 8-ohm position.Support the12volt.com

It being located ON the reciever and not on an outboard speaker selector switch, If your speakers are 4 ohm, when you select speakers A and B, the switch runs those speakers in series.  If you have 8 ohm or higher speakers, it parallels the 2 speakers for a 4 ohm minimum load  on each channel of the amplifier.

To check my above theory, place the switch in 4 ohm.  Turn on both A and B speakers.  Disconnect one of the speakers.  Does the other speaker quit?  Place the switch in 8 ohm or higher.  Do the same thing, the other speaker should play, whereas it should have quit with the switch in the 4 ohm position.

i am an idiot wrote: Place the switch in 4 ohm.  Turn on both A and B speakers.  Disconnect one of the speakers.  Does the other speaker quit?  Place the switch in 8 ohm or higher.  Do the same thing, the other speaker should play, whereas it should have quit with the switch in the 4 ohm position.

When I unplug a speaker on B, let's say the left one, the left speaker on A quits. This happens no matter where I set the switch. What does that mean?

That they are wired in series.