Space Age 2DCD "sings"

I have 3 AV-32s with 2CDC horns. I noticed one of the horns was a little bit “weird” when I tested it for my upcoming home system.
Here is a video of this strange occurrence

ALT:
http://quickalert.weebly.com/collection
By the way my friend was filming and found the zoom feature of my camera)

If anybody knows how to fix this alarm, I would appreciate it because I really don’t want to have to buy another alarm.