I have an Elk M1 that has been up and running for about a year. I just now got around to adding the Elk 45 Siren outside and connected it to Output 2. I can hear a high pitched noise coming from the siren constantly. It is like a big mosquito in your ear when you get within 30 feet of the siren. I don't like the noise because it draws attention to the location of the siren. Is the noise something to be concerned about and is my siren defective?