RLY8-XA as a speaker selector?


Active Member
I have an RLY8-XA that I picked up for a song that is collecting dust. Can it be used as a speaker selector for my HS speakers? I have one of the Elk $30 amps that I picked up here:


running 5 small "echo" speakers:


I would just run all the reds to the speakers and use the RLY8-XA to switch on an off the black wires (or vice-versa). My concern would be with let's say two off the other three would get louder which could affect the WAF :blink:

I have heard about people doing this before - wondering if anyone here has tried anything like it. If I can't use this thing for speakers, any suggestions for other ideas to put this to work?

I use two rly8-xa's for intelligent control of all my in-wall speakers.

You are right on the money with setup just run the positive wire for each speaker through each relay.

I use a sima speaker seletor with Impedance Protection powered by a pioneer reciever. And too be honest the difference in speaker volume when some speakers are off and some on is negligible. It has never been an issue for my WAF. And she is usually very picky when it comes to WAF ratings.

Good luck,
You "may" have a problem running five echo speakers off of that amp when all speakers are selected (on at the same time).

The Elk amplifier's output drive spec is 2 ohms (minimum). The echo speakers are 8 ohms so placing five in parallel yeilds 1.6 total ohms.
Not sure how to wire it but the Elk engineers told me that you can drive up to 8 of the echo speakers off of one of those amps.
In order to keep the total impedance within the allowed range of the amplifier, you typically need to wire the speakers in a combination of parallel and serial branches. This is discussed to some extent in the manual for the amplifier.

Depending on how you have them wired, the volumes will be different in different speakers due to this.

When you are selectively disconnecting certain speakers, you will affect the overall impedance. Whether this remains within the limitations of the amplifiers depends on the setup.

With a simple setup, you can't disconnect a serial speaker without affecting the speakers it is serial with. As mentioned above, you can't connect 5 speakers in parallel (which can be disconnected individually).

You may find that you need to have a couple branches with serial speakers. Then those branches could be combined in parallel. Each branch could be disconnected instead of each speaker.
since the Elk amp supports a 16 ohm load, you could just wire the speakers all in parallel with relay control, then add a 2-8 ohm couple watt resistor is series with the whole mess. That would keep your overall impedance from dropping too low.

Or, since you probably are only doing short bursts of speaking, you could gamble that 1.6 ohms isn't much lower than the rated 2 ohms. Usually it is a heating issue with low impedance and short speech shouldn't let it overheat.

EDIT: LOL, the Elk spec sheet/instructions (page 2 of the pdf) says it has a 2 ohm MAXIMUM load. so you could play dumb and get it replaced under warranty? BTW, that should be a 2 ohm MINIMUM load on their spec sheet.
AutomatedOutlet said:
Not sure how to wire it but the Elk engineers told me that you can drive up to 8 of the echo speakers off of one of those amps.
I'm willing to bet you can't "selectively" engage each speaker as you would have to do a setup as smee is suggesting.

Good point smee/wayne on the series/parallel/resistor scheme. I was just wondering though how this may work out if one would one total selectivity of all five speakers though.
This is all very interesting. I currently am driving the whole setup with no problems throughout the house. I was also looking at the cheap ~$20 amp that was discussed in another thread and simply switching the input, as opposed to the output, for each zone.

I have seen the equipment at www.hacs.com, and it looks interesting, but I am trying to avoid a $175 investment, besides which nothing is in stock there (either the old switcher or the new improved switcher). Additionally, when it comes time to do all-house audio (hifi), I will look into one of those switchers. I don't want to spend this much just for voice announcements. Right now for music I am using an old Yamaha amp with 4 speakers and the A/B switch inside it.

Hey, I forgot, but that RLY8-XA unit has "double throw" relays (instead of single throw). So couldn't you do something like the schematic below to avoid volume differences when switching various speaker on/off combinations??

As for the resistor coming out of the amp, could you place a small value there to avoid seeing below the two ohm limit that the amplifier wants to see?



  • Rly8speaker.jpg
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each relay switches between having a speaker on or using an equivalent resistor (dummy load). The amplifier sees a nearly constant load as it doesn't care if it is driving a speaker or a resistor.
What would I use to create that load? A resistor? Where can I get them? Radio Shack?

So many questions........ :blink: