It doesn’t need to be with a routine if all you want to do is turn off the siren. As long as the siren DTH has .switch capability, it will show up as a switch to echo and you can turn it on and off that way.
So name it “kitchen siren” or “backyard siren” or whatever you want and then it’s just Alexa, turn on and Alexa, turn off. The same as any switch. 
So @JDRoberts, which siren would you suggest? Least painful to tinker with…was considering the Dome vs. Gocontrol but browsing through the threads, seems like there is not write-up (dome) or issues with “device handlers(?)”.
Thanks for your input.
Different things work for different people. It just depends on what features are important to you.
Battery operated or wired or wired with the battery back up?
How loud does it need to be? In the US, sirens typically run anywhere from 80 dB to 110 dB. 80 is about the sound of a doorbell, 110 is about the sound of a smoke alarm.
Do you also need a strobe light?
Do you want to be able to customize how long the Tonys?
What sound do you want: siren wail, beat beep beep, Chime, or the ability to upload your own custom sounds?
Do you want to be able to use different sounds for different smartthings events? ( some sirens give you a choice of sound, but you can’t change the sound on the fly.)
Zwave, zigbee, or WiFi?
Does it need to be able to run locally with SmartThings?
Does it require custom code?
I’m not saying you can get everything you want in one device, but those are the main features where sirens will differ one from the other. But the answers to those questions will be different for different households. And of course there’s also the question of aesthetics.
How about “Alexa, turn off alarm” if alarm is a switch it would then be turned off, you could then use smart apps etc to make the alarms stop. At least that was what I was planning. I actually asked because I was wondering if my thought of how I could make it work was wrong. I do a lot of my smart apps using virtual switches. This way I can have a virtual switch called “Alarm” and saying turn it on/off would change it’s state and trigger what I want to happen. You asked if there is a way to do this “without adding custom apps” honestly I can’t make ST do anything I want it to do without Custom apps, Modified DTH, CoRE or something that isn’t a part of the basic product. In fact 90% of my devices are running custom device code so I can tweak them. For example when I buy one of these alarms I will modify the device code to add switch capability to so I can just directly call “off” and have it disable the alarm, etc.
Exactly what I was planning but good point that the trigger needs to not be something that is still happening.
I actually don’t plan to use this as a true alarm, just notifications and in one weird case make a sounds to distract my dog from doing something I don’t want her to do, haha.
I honestly don’t know if you can setup either SHM or SmartAlarm as a virtual switch. I haven’t tried using virtual switches yet so I’m sure another person would be better suited to answer that question than myself. I only had the ST system since December but from all the reading I have done on this forum, it appears to me that the more customization you have with ST the more prone to problems you have with this system so I try to keep things simple to be more reliable. I hope one day ST will have a native app like CORE, but until that time I’m trying to stay away from it and just use basic features.
Though I can tell you from experience do not name your Alarm setup with the word “alarm” if you want to use it with the Amazon Echo. The echo has native “alarm” commands and sometimes she get confused. On my setup, I call the appliance module “siren” and use the command “turn off siren” for example. When i used the word “alarm” she would work perfectly sometimes and others she would ask which “alarm” you were referring too.
Looks like am back to square one.
Hopefully i can narrow down my choices.
Thank you again for your inputs…
Here is my build. I strongly recommend building your own Siren/Strobe (much more flexibility with placement, can choose quieter or super loud siren, choice of strobe(s)/color).
@macombweare, we documented exactly how to use the Siren’s device handler along with different ways you can use the chimes/siren in your automations with SmartThings. You can find that by following this link.
Home automation can be pretty frustrating to get into - let me know if I can help in any other way!
Also, @Ron, I’m working on quantifying the volume right now, as I don’t have it on hand. Will get back to you with it!
Mike
link is dead(?)
Link required I login to AWS and then said ACCESS DENIED.
@mictha1 Seems to be throwing a 404 for me. I’m really interested in Dome’s siren, so get that fixed! 
Okay, now it should ACTUALLY be fixed. I used the wrong link - I edited the original post, or you can follow this link.
Mike
Google home can control sirens easily. If I say tell google to turn on panic all 3 of my sirens go off. I found this out because I had my sirens in rooms and when I asked to turn on a room the siren went on too!
Using a pocket socket with a non-networked siren works very well if you just want one siren sound for every event.
If you want different Siren sounds for different events, then a smart device will give you more options.
So as always, different things work for different people. Choice is good.
I have an extra GoControl siren for sale. PM me if you want. I don’t need 2 in my house. they are LOUD
This is another reason why I was strongly against removing the switch capability from the Dome Siren handler.
Any Device which accepts an on/off command should always have capability.switch so that you can set up a minimote to turn it on and off using the official smartlighting feature. I would think this is particularly important for sirens which may have been placed in fairly inaccessible places. 
As someone who is a wheelchair user, I am particularly aware of this issue, but it holds true for any household. It’s way easier to hit a button on a minimote and turn on/off a group of devices then to have to go around the house and physically access each device. Or even to open the phone app and individually access them.
Including capability.switch is also the easiest way to group multiple devices to come on and off together, using the official smartlighting feature.
And, of course, allows for Alexa or Google Home to turn the device on and off by voice without needing any special code.
My Echo dot is not seeing the Dome siren? i have ran “Discover devices” several times but the Dome siren is not showing up.
weve have strong winds here in Michigan and it blown open my basement window and triggered the alarm which is a good thing…the Dome Siren and my window sensors work… the problem is i am not able to Ask Alexa to turn the Siren off! i had to look for my phone, open the Smartthings app, then go to My Home, then look for Dome siren under things then turn it off…
Which device type handler are you using?
If you are using a device type handler with capability.switch, then the Siren should show up as a switch to Alexa.
But if the device type handler does not have capability.switch, Alexa probably won’t see it and you have to start using workarounds.
