Enhanced synesthesia (also referred to as a "siren's song") is the ability to visualize sound waves as colorful light waves and manipulate these lights by combining them with a particular emotion.
- Emma Coolidge possesses this ability naturally.
- Peter Petrelli has replicated this ability from Emma but later discarded it in favor of space-time manipulation.
- Chris Coolidge was the first person chronologically to possess this ability.
Emma is able to see sound as a variety of colors. Some colors appear dim while others are bright and vivid. At first, Emma could only see seemingly random lights being emitted.
As time went on, Emma began to see more and more lights everywhere she went. When noises were typically loud and pressured, red lights usually appeared, but when sounds were calm and soothing, more peaceful colors would appear. While in a bad mood, Emma played a cello at her home and, much to her surprise, was able to make a large crack on a wall in her apartment. However, when she plays the cello at other times, many more colors were generated. While time is frozen, Emma also seems to be able to move the lights simply by touching them.
Emma did not believe that it was actually her that caused the concussive blast from her cello but, after a meeting with Samuel Sullivan, Emma learned that she is able to "combine" her emotions with her music and that her fear created the powerful blast. Samuel tells her that her music can lure people to her and, when Emma tests this out by focusing on Ian Michaels, Ian and a large crowd are drawn to her. She later validates this again by drawing Peter Petrelli to her apartment. While under Eric Doyle's control, Emma is forced to use this power to summon thousands of people to the Carnival, but when Sylar distracts Doyle and he loses control over her for a moment, Emma manages to purposely create a concussive blast which defeats Doyle.
The luring effects of Emma's melody can be channeled through amplifiers.
After replicating this ability from Emma, Peter was able to see bright colors flow from a trash can after he kicked it to the ground. Peter is still able to hear the sounds that he sees and, like Emma, he is able to create colors by playing soothing sounds such as music from a piano. Peter has yet to demonstrate the capacity to affect music by channeling his emotions.
Chris possessed this power since at least 1963 and could see music as color like Emma. He may also have been using it to draw crowds to him as well. Chris uses a guitar and harmonica to channel his ability. He is noted by Angela to not be a great musician but good at what he is doing. He has also shown that he is able to create blasts from his guitar which hit the policemen. He uses this to attack a police officer.
He later attempts to use this ability to soothe the crowd but is killed before he could succeed.
According to his assignment tracker profile (which calls his ability both "empathic manipulation" and "biological empathic manipulation"), Chris was able to draw crowds of thousands to his concerts, and his music apparently affected and inspired people like no other. His profile also states that, as Chris's popularity grew, his ability amplified. Also, due to the era's disenfranchised youth, it was very easy for Chris and his empathic transmissions to take over his audience.