My house has quite a few outdoor speakers, 6-8 of them. My amp has a "Zone-2" stereo output that I'm planning to drive them with. Each set of speakers has a rotary volume control on a wall in the house nearby.

It's not practical for me to take down and disassemble the speakers to check their ratings. But if I wire them all in parallel, can I simply add 6-ohm resistors to one pole of the amp's Zone-2 speaker terminals before it feeds all the speakers?

UPDATE: Based on comments, it looks like this is not a viable solution. I did find this speaker selector with "protection"; can anyone weigh in on how effective these are? The Q&A says it applies a fake load to protect the amp. Another source says it uses resistors and not a transformer.

I have hooked one speaker lead up to the wire that runs through the house and the volume control to the outdoor speaker, and with full rotation of the rotary control it sounds about the same volume as a similarly-sized one I have hooked up in parallel inside (if that answers the question about a 100V system).

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    \$\begingroup\$ Assuming normal 8 ohm speakers, if you wire 4+ in parallel, the total resistance will go down to =< 2 ohm. If you place a 6 ohm resistor in series with that 3/4+ of the power will be consumed by the resistor rather then the speakers. \$\endgroup\$ Apr 25, 2021 at 8:49
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    \$\begingroup\$ Are you sure this isn't a 100V line system with transformers and volume control for each speaker? Please your question and add a link user manual for the amplifier \$\endgroup\$
    – Transistor
    Apr 25, 2021 at 9:01
  • \$\begingroup\$ It might be better if you could re-arrange the wiring such that they're not all in parallel, but rather a series/parallel combination instead. \$\endgroup\$
    – brhans
    Apr 25, 2021 at 14:01
  • \$\begingroup\$ Thanks for the responses. This sounds sub-optimal. I might have to instead use a switcher and just decide which outdoor speakers I want to use from time to time. This is the receiver: nadelectronics.com/wp-content/uploads/2016/09/… \$\endgroup\$
    – Oscar
    Apr 27, 2021 at 1:27

1 Answer 1


You can use a 70V audio line transformers. One connected in reverse to the amp and then each speaker has its own transformer, everything will remain matched and no power lost is a resistor. You need to size the one at the amp big enough to handle the power of all of the speakers then smaller ones can be used on each speaker.


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