III. How Does it Work?
Instead of a speaker, the talkbox uses a compression driver, such as that made by JBL, Altec, and Electro-Voice. These drivers are actually designed to be used with PA systems to reproduce high frequency sound. A length of vinyl tubing is inserted into the open end of the driver. The other end of the tubing is placed in the performer's mouth to modulate the sound.
The talkbox is connected to the speaker output of the guitar amp. If a single amp is used, the output from the talkbox is plugged into the speaker cabinet. A switch on the talkbox sends the guitar amp output to either the internal horn driver of the talkbox, or direct to the speaker cabinet.
Note that a microphone is an integral part of the talkbox effect, since without it, the effect cannot be heard over the din of the average band.