I just plugged in a 12-volt self-driven siren to the Elk panel, and noticed the siren was producing a low-level siren sound. I checked and saw I had that output set to siren mode so I switched it to voltage mode, but the low-level siren sound is still happening. What can I do to silence it during non-alarm conditions?
Elk siren whispering to me during the day
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I put a resistor in parallel with the siren and it's quieter now, but still making a little bit of noise. It's definitely much better than it was. I'll assume that this is just a result of the siren supervision (low voltage or low current leak through the device to make sure it's still there), and hopefully it won't bug anyone at the current level of volume.
Sometimes the Piezo sirens do this from the supervisory voltage as you stated. Try playing with the resistor value or call ELK Tech support and ask what value resistor they reccomend.
Spanky
Senior Member
Normally the supervision current on Output 2 is what is causing a low level sound on a self contained siren driver. As mentioned above, a parallel resistor will reduce the voltage drop across the siren and keep it from turning on. You can go down to a 100 ohm 1/2 watt and it should stop sounding or any value that works above that.
Piezo sirens are prone to making a sound because they draw such a small amount of current and turn on easily.
Piezo sirens are prone to making a sound because they draw such a small amount of current and turn on easily.
BraveSirRobbin
Moderator
Curious as to the type/model of piezo you are using. My friend and I are using (multiple) Moose Piezos and we both don't have this problem. Doesn't the solution of installing an additional resistor defeat the main advantage of using a piezo because of its low current draw? 
Curious as to the type/model of piezo you are using. My friend and I are using (multiple) Moose Piezos and we both don't have this problem. Doesn't the solution of installing an additional resistor defeat the main advantage of using a piezo because of its low current draw?
The supervisory current would only be about 10 mA or so. The piezo's probably draw 70 to 100 mA each so it is really minimal in my opinion. I believe the bell/siren circuit rating is 1 A. So you could hook about 10 piezo's to the outputs compared to less than half that of other types of sirens.
Some piezo's are almost dangerously loud. For UL and NFPA requirements in Residential applications 85 dB at 10 feet is the minimum requirement. Imagine being less than 10 feet away where it might be 120 dB or more. It can damage your hearing easily if you are not careful.
BraveSirRobbin
Moderator
Actually if you think about it, putting in an additional 100 ohm resistor in parallel is almost like adding an additional piezo siren isn't it (in terms of current draw)?
Yes, this is the exact reason I like to use them!
Yes you are correct if you have to get down to 100 ohms. Typical supervision is 2.2K so teh current is very low. Its the price you have to pay sometimes.
I just noticed that my newly-installed self-contained siren (ELK-45 is the stainless enclosure) is whining at idle too. For the resistor, I assume it needs to be put at the siren, to keep supervision meaningful?
Otherwise, I also happen to have a ELK-44 speaker. Except for the (2x - since I am on millimiser anyway) loss of power if using it vs. the siren version, would it also whine or not?
BTW, talking about sirens, the most confusing option is the out2 hookup (G26). In RP, there are "Siren output" and "voltage out" options. If I interpret these correctly, "siren output" is for speakers and "voltage out" for self-contained sirens (pretty confusing)?
Laurent
Otherwise, I also happen to have a ELK-44 speaker. Except for the (2x - since I am on millimiser anyway) loss of power if using it vs. the siren version, would it also whine or not?
BTW, talking about sirens, the most confusing option is the out2 hookup (G26). In RP, there are "Siren output" and "voltage out" options. If I interpret these correctly, "siren output" is for speakers and "voltage out" for self-contained sirens (pretty confusing)?
Laurent
Spanky
Senior Member
Self contained sirens are a speaker with the siren driver electronics built into the speaker. Just add 12 VDC to turn it on, therefore the M1's output 2 needs to be set to voltage output.
If using a speaker only, set output 2 to siren output which drives the speaker with a siren audio tone.
If using a speaker only, set output 2 to siren output which drives the speaker with a siren audio tone.