The intentional reduction of bandwidth, or adding of distortion or noise, to a signal. The intent is to reproduce the effect of receiving the signal through an earlier-era receiving device, such as a 1960s-era portable radio, or a pre-1980 television, or a POTS telephone line. A variety of techniques are used, such as bandpass filtering to remove bass and treble, bit crushing, or playing the signal through a loudspeaker and re-recording it using a low-bandwidth microphone. Additionally, to give a "feel" for the eariler-era technology, samples of typical noises produced by those devices are sometimes mixed in, such as AM radio hetrodyning, or run-in/run-out groove noise from an old phonograph record.