There are several different types of rechargeable speakers that can be used to play music from various audio playback devices. Docking speakers are quite common and allow a portable device, such as an MPEG-1 Audio Layer 3 (mp3) player, to be placed in a small dock on them and then audio data is sent from the device to the speaker. There are also portable rechargeable speakers designed as individual units that can be connected to an audio device through cables. Different types of speakers can also be categorized based on how they receive a charge, including those that require batteries or can be plugged into a wall socket as well as solar-powered units.
Rechargeable speakers are typically designed to function with portable audio devices, which may not have sufficient energy to power external speaker systems. Docking speakers for portable electronics, for example, can usually hold a charge and include a small port into which a device can be connected. Once the audio device is secure, then it can be used as normal and the signal from it is sent into the rechargeable speakers for playback. Some of these speakers even charge the device that they are connected to during playback, allowing for longer listening times from such devices.
There are also rechargeable speakers that are designed as individual units, much like bookshelf speakers, which can be connected to an audio player. These can connect to small portable devices through cables, though unlike docking speakers, they usually have connections that can also function with larger audio players. Such rechargeable speakers can be quite portable, potentially smaller than the docking models, and allow someone to easily setup an audio system at any location. These devices can be fairly modular as well, allowing users to set up varying numbers of speakers with a single system, depending on the listener’s needs and the system available.
The different methods through which these devices can be recharged should also be considered with regard to rechargeable speakers. Many small, portable speakers can require batteries, and rechargeable batteries can typically be used to make simple, pocket-size speakers more easily useable. There are also rechargeable speakers that include a connection that can be used to plug them into a wall outlet, allowing a listener to charge his or her speakers ahead of time and then listen to them for many hours. Some outdoor speakers can include solar-powered rechargers that are connected to them and allow them to receive a charge through exposure to sunlight.