2 pairs of 8Ω with Sherwood RX-4109 receiver

[dbguerrero]

I have a Sherwood RX-4109. I do have 8 ohm speakers BUT was wanting to connect a 2nd pair that are also 8Ω. The manual says to use both A and B (2 pairs) they must be 16Ω. For some reason (& may just be me) seems counter-intuitive to me. Should I be able to use both and do I need resistors on the wires to do so and what type/rating?

 

[dbguerrero]

MERGED QUESTION
Question from dbguerrero : "2 Pairs (A & B) with Sherwood RX-4109 Receiver+amp"

I have a Sherwood RX-4109. I do have 8 ohm speakers BUT was wanting to connect a 2nd pair that are also 8Ω. The manual says to use both A and B (2 pairs) they must be 16Ω. For some reason (& may just be me) seems counter-intuitive to me. Should I be able to use both and do I need resistors on the wires to do so and what type/rating?

 

[americanaudiophile]

When you connect 8 ohm speakers in parallel they present 4 ohms to the receiver. It seems your receiver is designed to work with not less than 8 ohms.
You could put non inductive high power resistors in the wires but it would be better to connect them in series.
The best solution is to use a impedance matching speaker selector. That would allow you to select either or both pairs for use. Some have volume controls for each pair. There are also in wall volume controls that have impedance matching built in. Having in room volume control might be nice.