In digital audio production, a butt splice is the abrupt connection of one audio file to another audio file so that they become one continuous audio file. The main alternative is a crossfade in which a smooth transition is made between two files, the volume of one file being lowered while the volume of the joining file is increased until it completely replaces the sound from the first file.
In analog audio production, butt splicing is accomplished using a splicer , a device that contains a track where the ends of two tapes being spliced together are laid down one over the other. The person splicing the tapes makes a vertical slice through both tapes with a razor blade and then pulls a piece of splicing tape (something like transparent Scotch tape) over the cut and trims the edges. Since such splices can come apart, a tape with a number of editing splices in it would typically be dubbed onto a spliceless tape.