Multiple Input Adapter (Crab Box)

Last Updated: 16 October 2017 at 14:51


The multiple input adapter box has a variety of cables and connections (RCA, XLR, 1/4" and 1/8" phono jacks) that allow connections to be made from almost any electronic audio source (laptop computer, tablet, cell phone, DVD, VCR, CD, MP3 player, mixer, and so on) to the house sound system (the XLR mic-level input of the typical chapel and cultural hall). However, the adapter box cannot be used with mic-level audio sources (for example, a microphone). Because of its many cables, the box is sometimes referred to as a crab box.

The crab box comes in two models: EJ-10 (gray case) or EJ-8 (black case). Unlike the EJ-8, the EJ-10 has the ability to connect to telephone lines, so it can either feed audio to a remote site or receive audio through a telephone connection. For example, it can be used to back up the audio of a Church broadcast if the satellite or Internet stream fails.

Older meetinghouse sound systems do not have a line-level input (such as an RCA jack). Where this is the case, the EJ-8 and EJ-10 allow the connection of any non-mic-level signal into the building sound system. Since the EJ-8 and the EJ-10 each have a volume control, various input devices, such as a DVD player with soft audio, can be adjusted for appropriate sound levels.

Both boxes have a hum switch, which can help reduce unwanted noise in the system. The Church issues at least one audio adapter box to each building. It is usually stored in the library.

To learn more, visit:

EJ-2 Plus Information
EJ-8 Information 
EJ-10 Information