The Old World Sirens

Old-world communication devices are a strange thing. Widely useless, as their networks have long since collapsed or decayed, they're best used for the valuable metals on the inside. However, if you take the time to charge them, then scroll through the empty channels, you just might hear the sounds of the Old World Sirens. 
It starts as a single voice, often saying something that the listener(s) can't quite make out before starting into their song. Faint singing, accompanied by many sorts of instruments, create a slow and mournful tune that pulls unfortunate listeners in, if they're in the wrong place at the wrong time. The genre isn't always the same, nor the arrangement or accompaniment, even the singer changes between performances. 
Well, saying it changes between channels is a rather large misnomer, as there isn't a set frequency that the song can be heard on. It's not even the same between individual listeners hearing the same broadcast, a source of tension that becomes more clear with the next effect we'll discuss.  
Those that hear the sound of the Sirens can develop a...connection to the music. They start to seek it out, sneaking away to listen to it whenever they can. It's a rather personal experience, as well. Should someone interrupt their listening session, the affected will react like they were caught doing something they shouldn't, turning off the music and trying to explain, even if the other person doesn't really seem to care or understand what they're talking about. 
The connection only grows from there, all the way to proper obsession. 
Some reports indicate the listener attempts to lay claim to the music and the players themselves. No one else can listen to them, and if they do, they've stolen something from the original listener. Something that has to be retrieved. Other times, the listener will attempt to find the point of broadcast with a feverish need to find the persons who produce the music. Maybe they have more of it?
In a few rare cases, multiple people have heard the music at the same time, and it brought them closer. Too close. They practically worship the music, resulting in small cults that share the behavior of the other singular listeners. Dangerous, but often ignorable as they keep to themselves. There are a few amongst them that can't, and should not be ignored. The most prominent of these organizations is the Communion of Angelic Voices, who purposely expose others to the music that has caused them to form their organization. They have become much more violent in their attempts since their founding, causing official law enforcement to drive them from most civilized places they make themselves known within. Whatever their end goal is, it has not been stopped by such actions.

Purpose

Completely unknown. The why and how of its function and operation are completely indiscernible, even to those with advanced and sensitive equipment. 
For all intents and purposes, there shouldn't even be any music playing in the first place, let alone music that rewires the brain into obsession.

Historical Details

Public Reaction

It sounds beautiful, doesn't it?

Medium

Analog Recording, Audio

Authoring Date

Unknown, thought to be the very end of the world