Researchers at Harvard University however have designed a new kind of speaker that operates with ionic signals, a technology that brings many interesting properties with it. Electrical signals carry information with electrons, a subatomic particle. Ionic signals however carry information with ions, which are charged atoms or molecules, and are thus much larger than electrons. This difference has made ionic technology hard to develop, as ions can be hard to move as quickly as needed. The Harvard researchers decided to prove they could be move very quickly by designing an ionic speaker, which consists of a sheet of rubber sandwiched between layers of a conducting, saltwater gel. With this configuration, the researchers realized that instead of having to move the ions, they could instead change their distribution, a much faster option. In fact, it is fast enough to respond to audible frequencies by 20 Hz and 20 KHz, so the researchers played some Peer Gynt on it.