Screamer has the ability to manipulate sound within roughly a mile's radius. She used it to amplify her voice, alter it to match others, throw it to speak directly into people's ears, or cancel out sounds she doesn't want to hear. Her abilities also allowed her to hear sounds in any given area.
It is almost impossible to cancel her out as she can transmit sound, and by extension words, through multiple mediums. This includes bone, thus earplugs or earmuffs would be ineffective. She can modulate the sound to the point that people will hear what she is saying as if it is the voice within her head, though she may have been aided in this with Cherish.
She earned her name as Screamer from a favored tactic of hers, overloading everyone in her range with a deafening jarring scream.
The original Screamer may have had greater control over then was showcased by her clones in story.
↑ 1.01.1Together, we’d gone over the various members of the Nine, past and present, we’d detailed battle plans, the techniques we knew about, even contacted heroes who had encountered them in the past, for stuff that might not have gone on record.
But Screamer was called screamer for a reason, and there wasn’t a lot we could do to stop it, not unless we wanted to deafen ourselves.
Crimson was three stories up the side of the building when Screamer used her namesake power. She could ensure that everyone within a mile’s radius could hear her voice as if she was right next to them, and she used it now, producing a high-pitched, full volume scream, right in my ears. In Golem’s ears. Everyone’s ears.
I joined Golem in doubling over, using my hands to try and ward off the sound. It didn’t help as much as it should have. It was loud, deafening, and it was leaving Golem vulnerable as Crimson closed the distance. He wasn’t recovering fast enough.
Bugs flowed into Screamer’s open mouth, much as they had with Alexandria. - Excerpt from Sting 26.2
↑“Screamer,” I informed the others. Early Nine member, psychological warfare, pressure, distraction. Sound manipulation. Her power meant her voice didn’t get quieter as it traveled great distances. That wasn’t the full extent of-
“Nice weapon,” Her voice sounded in my ear, at a normal speaking volume. I didn’t flinch. I could sense my surroundings with my bugs, and I could hear things with them, hear how the sound panned out in a weird way over the entire area.
“You’ve got friends, Theodore. I sure hope they aren’t planning on helping you.”
It was a sinuous sound, seductive in how convincing it was. Every time she spoke, she sounded a little more like me. It would be the same for the others, hearing themselves.
She was somewhere in the area. The question was how she’d gotten a sense of our voices so quickly. There was supposed to be a limit to how quickly she could pick up on that stuff just from overhearing us. - Excerpt from Sting 26.2
“No, I’m not standing next to you. Borrowing Screamer’s power to broadcast, to have a little chat.”
No. Couldn’t afford to listen to him. If any of us were problematic, or if it was someone listening in, anything he said could be the catalyst for the end of the world.
Problem was, Screamer was a bitch to shut down. Ear plugs wouldn’t be any guarantee. If she was forced to, she would use the vibrations of people’s bones to transmit words.
Jack continued, “I confess, I do like this part. The chatting. It’s safe to keep my distance, but it’s boring, really. You challenge somebody, pit mind against mind, but how much do you truly get to know them?”
“Move,” I said. “Fan out, find Screamer as soon as possible.”
Jack spoke, his voice smooth. Or Screamer spoke, mimicking what he was saying, quite possibly in the exact tone and cadence.
“Weaver.” Jack said. Screamer repeated the word after him, and it carried through the air, an echo. - Excerpt from Sting 26.6
↑Screamer’s voice reached all of us. “Cocky, cocky.“
Screamer turned her head, swatted at the bugs that crawled on her face, and then spoke, silent to the insect’s hearing.
Winter and Crimson reacted.
Sure hope your boy can fight. Screamer was talking in my head again. Not telepathy, only hearing a voice that sounded damn close to the one in my head.
“Fuck off, Screamer,” I muttered.
“Grue no!” Imp’s voice. I flinched despite myself, before I remembered they weren’t anywhere nearby.
↑Though it’s somewhat justified in this instance as they don’t retain their full memories – only cobbled-together personalities and histories. - Comment by Wildbow in Sting 26.3
↑The entity observed the ongoing conflict. No less than five seconds after it had been trapped, two figures had emerged from a doorway between worlds. The entity could see the paths forming, trace them back to the source. Another world, a living world without a shard occupying it.
They engaged the eight with their own perception abilities, intervening to assist a group of others. As a pair, they opened fire with guns, then waded into hand to hand combat.
↑Cherish was acting as the eyes, Screamer as communications. No doubt Screamer -all nine of the Screamers- was providing communications between this group and the nearest group of Nine. She was talking, in a low and steady voice, but her voice wasn’t more than a murmur. No doubt someone in a more distant location was receiving the intel at a normal volume. - Excerpt from Sting 26.2