Light physical alterations were made to the device to allow tape to pass from the recording head on the right to the playback head on the left. Sounds are recorded in through the device’s internal stereo microphones (located just above the speakers in the top corners) onto a tape and then played back a short time later through the device’s built-in speakers. Acoustic feedback causes the sound of the speakers to be recorded back onto the tape to be colored by the system and heard again. Some light electronic additions have been made to allow for more flexible signal output for amplification and recording. There is also an added feedback path that can be engaged to send electronic signals from within the device directly to the record head. This device uses consumer cassettes that have been modified to allow the tape to pass out of one shell through a slit in the side and be taken up by the opposite reel in a second shell.