Echo cell
From MediaWiki
An echo cell is a piece of technology that absorbs sonic waves and redirects them outwards.
Fiction
Marvel UK Generation 1 comics
An echo cell was built into Buster Witwicky's battlesuit by Wheeljack.
When Buster used the battlesuit in battle against Frenzy, he unknowingly activated the suit's echo cell, absorbing Frenzy's sonic attack. The absorbed attack was then fired out, incapacitating the Decepticon. Robot Buster!
