How to use Elk Relays as speaker switches?

[Galun]

It appears that some of the speaker selector switches that claim impedance matching or amp protection just put a small, high power resistor in series with each channel (left and right) to limit how low the resistance that the amp sees can go. With a 3 ohm resistor in series and from 1 to 8 pairs of 8 ohm speakers the resistance (actually impedance...) would vary from 11 ohms for one speaker (8+3) to 4 ohms for all 8 (3+8/8). That seems pretty good and is a lot less complicated than the series/parallel switching for the other unit posted. If you want to have a minimum of 8 ohms just use 7 ohms for the added resistance. Max would be 15 ohms. If you want to allow all speakers to be open put an 8 ohm resistor in place of one set of speakers.

The down side is not being able to adjust the individual levels, the heat generated in the resistors at high volume levels, and limiting the power delivered to much less than the amp output (when all the speakers are on). The sound output will also vary with how many speakers are on. But it is simple and cheap so if you can live with the limitations it may work fine for you.

Hum. My speaker selector does indeed have a 50W 3 ohm resistor at each channel, and looking at the circuit board it does appear to be in a series with the amp input.

So maybe I only have 1 ohm of resistance with the speaker wiring, but the amp sees 4 ohms with the 3 ohm resistors already in the series. How do I test for this? Turn all relays on so the speaker resistance is 1 ohm, then measure the resistance at the amplifier input and it should read 4 ohms?

EDIT - just tested it out and this is exactly the case. There is a 3 ohm resistor wired in series between the amp and the parallel wiring of the speakers within the speaker selector. With all six zones on, 8x 8 ohm speakers, I see 1 ohm at the speakers and 4 ohms at the amp. With 4x 8 ohm speakers on, I see 2 ohms at the speakers and 5 ohms at the amplifier. With 2x 8 ohm speakers on, I see 4 ohms at the speakers and 6 ohms at the amplifier. So I think my original idea worked.

Next idea - I want the elk to make voice announcements through some of these speakers via output 1 on the M1G. I am initially thinking about a source sensing a/b switch. The sinks goes into a and the elk output goes into source sensing b, and the switch output to my speaker selector. How is this idea? Any other ideas?

Thanks!

 

[apostolakisl]

Three probs I see with that.

1) Some lower quality amps are not OK with 4 ohms (require 8)
2) Turning speakers on and off will change the volume for all of the other speakers.
3) You have one extra piece of equipment (the speaker selector), which could be elminated by putting the resistors directly on the Elk relay board.

But, if it suits you, great.

Lastly, there is a post in here somewhere which gives the wiring diagram for converting the speaker out from the Elk into a line out that you can connect to a line in on your amp. I don't know how you would switch over, my home audio distributor/amp has a "PA" input that has that function built in.

 

[tmbrown97]

Lastly, there is a post in here somewhere which gives the wiring diagram for converting the speaker out from the Elk into a line out that you can connect to a line in on your amp. I don't know how you would switch over, my home audio distributor/amp has a "PA" input that has that function built in.

The elk itself won't really have the power to drive this directly - as Lou said you may want to find these posts about integrating a separate amp and tie that inline with the speakers. Use that with your source-sensing device. Problem with those source-sensing switchers is that they take too long to switch - the announcement could be half over before it confirms the switch. You'll want to see if you can find specs that indicate that i'll happen in time. You could probably use Elk rules with relays to make it faster (there's rules around when the amp turns on, etc).

 

[apostolakisl]

The elk itself won't really have the power to drive this directly - as Lou said you may want to find these posts about integrating a separate amp and tie that inline with the speakers. Use that with your source-sensing device. Problem with those source-sensing switchers is that they take too long to switch - the announcement could be half over before it confirms the switch. You'll want to see if you can find specs that indicate that i'll happen in time. You could probably use Elk rules with relays to make it faster (there's rules around when the amp turns on, etc).

I haven't noticed the "whenever" rules that let you create an action to preceed a voice output, but that would sure make switching easy. Just run your normal line-in to the amp through the NC side of a relay and the Elk side through the NC side and have the relay switch over during an announcement.

 

[apostolakisl]

Found It!

It's under "miscellaneous system -> other -> audio amplifier"

You would need two rules

whenever audio amplifier status turns on
then turn output x on

whenever audio amplifier status turns off
then turn output x off

Done!

I think I might add this to my system.

 

[Galun]

What is the power rating of the elk output 1? Can it drive 2x 32ohm speakers in keypads + 8x 8 ohm speakers? Doesn't look like it can huh...

I tried to search for posts that tie in an amp but have no luck. Probably not using the right keywords... Can someone point me to research down this path?

Thanks!

EDIT: thought about it a bit more... how about this.

Input sources: Sonos L/R, Elk -/+ from output 1. Output source: amp line in L/R.

Relay 1: NC = Sonos L, NO = Elk - , COM = output to amp line in L.

Relay 2: NC = Sonos R, NO = Elk + , COM = output to amp line in R.

If the relays are off, audio is directed from sonos through the amp to my speakers. If the relays are on, it switches over to the elk, goes to the amp, and to my speakers.

 

[apostolakisl]

You can't do what you said because you will be mixing negatives and positives.

Take your Elk line-out from the above wiring diagram and split the positive and negative so you have 2 positives and 2 negatives.

Relay 1: NC line-in music L+, NO line-in Elk +
Relay 2: NC line-in music L-, NO line-in Elk -
Relay 3: NC line-in music R+, NO line-in Elk +
Relay 4: NC line-in music R-, NO line-in Elk -

The output from the relays (the common central one)
Relay 1 to amp L+
Relay 2 to amp L-
Relay 3 to amp R+
Relay 4 to amp R-

 

[Galun]

Now I am confused on how to wire the system.

In my current "working" setup, I have the Sonos sending an amplified signal out to 6 speakers, being switched by the elk relays.

When I try to add the Elk announcements from M1G output 1, the problem that I see is that output is insufficient to power 8x 8ohm speakers + 2x 32ohm speakers from my two keypads. I need to add an amp.

I have a few AV receivers lying around, but they take line level red/white RCA plug inputs. I don't see L+/L-/R+/R- for inputs. I just see L and R RCA plugs. So how do I get my Sonos and Elk audio sources to go through the Elk relays into the amp inputs?

Thanks!

 

[apostolakisl]

You need to buy RCA plugs and solder them together with positive to the central pin and negative to the ring, just like in the photo above. The only difference is becuase Elk is mono you will need to split the positive and negative into two each so you can have sound on both the left and right speakers. Of course you will not solder the RCA jack on until after it comes out of the relay. You will also need to cut the RCA plug off of the end of your wires comming out of your music source so you can wire them into the relay. They can be bought at Radio Shack or ebay for cheaper.

Come to think of it, It would be easier just to take two suffient length RCA wires and cut them in half. Plug the RCA jacks into your music line-out and then strip the other end and use the pos/neg wires to run into the elk relay. (one pos/neg for left, one pos/neg for right).

Take the other half of your cut-in-half RCA wires, strip them, and use it to come out of your Elk relay and into the RCA line-in on the back of your amp.

Create your line-out from your Elk using the diagram above except don't attach the RCA jack. Split the wire and run them to your Elk relay as described above.

 

[Galun]

You need to buy RCA plugs and solder them together with positive to the central pin and negative to the ring, just like in the photo above. The only difference is becuase Elk is mono you will need to split the positive and negative into two each so you can have sound on both the left and right speakers. Of course you will not solder the RCA jack on until after it comes out of the relay. You will also need to cut the RCA plug off of the end of your wires comming out of your music source so you can wire them into the relay. They can be bought at Radio Shack or ebay for cheaper.

Come to think of it, It would be easier just to take two suffient length RCA wires and cut them in half. Plug the RCA jacks into your music line-out and then strip the other end and use the pos/neg wires to run into the elk relay. (one pos/neg for left, one pos/neg for right).

Take the other half of your cut-in-half RCA wires, strip them, and use it to come out of your Elk relay and into the RCA line-in on the back of your amp.

Create your line-out from your Elk using the diagram above except don't attach the RCA jack. Split the wire and run them to your Elk relay as described above.

Cool, thanks. I think I got it.

Any idea how to switch on and off my receiver with the Elk?

Thanks!

 

[tmbrown97]

Depends... what happens to your receiver if you just yank the power on and off? Will it resume as you want it to?

It looks like your wattage requirements would be too high but if it wasn't for that, the Elk800 is a cool little amp that can be tied in.

If you'll get the desired result by just interrupting/restoring power to the amp, you can use a variety of methods - either via powerline control or the use of a Relay or Contactor. That said I've noticed that all my receivers take about a second or 2 before audio comes out so turning them off may be a pita because of the delays involved.

Also - the audio output you're going from the Elk is amplified which will be much less desireable... Spanky once posted how to get to the low-level (pre-amplified) audio on the board - but a handful of searches across the forums here and the Elk site yielded no luck. Maybe someone else can help locate it.

 

[apostolakisl]

Also - the audio output you're going from the Elk is amplified which will be much less desireable... Spanky once posted how to get to the low-level (pre-amplified) audio on the board - but a handful of searches across the forums here and the Elk site yielded no luck. Maybe someone else can help locate it.

The diagram I posted is that.

 

[Galun]

Depends... what happens to your receiver if you just yank the power on and off? Will it resume as you want it to?

It looks like your wattage requirements would be too high but if it wasn't for that, the Elk800 is a cool little amp that can be tied in.

If you'll get the desired result by just interrupting/restoring power to the amp, you can use a variety of methods - either via powerline control or the use of a Relay or Contactor. That said I've noticed that all my receivers take about a second or 2 before audio comes out so turning them off may be a pita because of the delays involved.

Also - the audio output you're going from the Elk is amplified which will be much less desireable... Spanky once posted how to get to the low-level (pre-amplified) audio on the board - but a handful of searches across the forums here and the Elk site yielded no luck. Maybe someone else can help locate it.

Thanks. Yeah I looked into the Elk-800, but I am not sure if 10W is enough. Plus, I need to buy that and then a signal sensing A/B switch. I do have 4 relays left over and I have an amp lying around, so Lou's method is much cheaper (just a couple resistors / capicators and wires to turn Elk output 1 into a line level output).

If I leave the amp on (not off/standby), how much electricity am I wasting? Is there some way to take the receiver specs and figure that out? When the amp is on but no music going through (not amplifying anything), does it just consume idle power like in standby mode?

 

[apostolakisl]

Yes, amps consume power when on even if no sound is comming out. They do consume less power then when actually making sound and will consume the most power when making loud sound. The only way to know is to get a kill-o-watt and test it. I bet you are looking at 60 watts or so for an idle amp of reasonable size.

 

[Galun]

Yes, amps consume power when on even if no sound is comming out. They do consume less power then when actually making sound and will consume the most power when making loud sound. The only way to know is to get a kill-o-watt and test it. I bet you are looking at 60 watts or so for an idle amp of reasonable size.

I wired it up and was able to succesfully switch between Sonos sound and Elk sound. On the Sonos sound side I did make it line level output like in the document described above.

The problem now is that I get a popping sound in the speakers when I switch. On the elk sound side I also hear a lot of humming.

Any thoughts? Thanks!