A reverb effect, or reverb, is an audio effect applied to a sound signal to simulate reverberation. It may be created through physical means, such as echo chambers, or electronically through audio signal processing. The American producer Bill Putnam is credited for the first artistic use of artificial reverb in music, on the 1947 song "Peg o' My Heart" by the Harmonicats. Spring reverb, created with a series of mounted springs, is popular in surf music and dub reggae. Shimmer reverb, which alters the pitch of the reverberated sound, is often used in ambient music. Gated reverb became a staple of 1980s pop music, used by drummers including Phil Collins. Echo chamber The first reverb effects, introduced in the 1930s, were created by playing recordings through loudspeakers in reverberating spaces and recording the sound. The American producer Bill Putnam is credited for the first artistic use of artificial reverb in music, on the 1947 song "Peg o' My Heart" by the Harmonicats. Putnam placed a microphone and loudspeaker in the studio bathroom to create an echo chamber, adding an "eerie dimension". A plate reverb system uses an electromechanical transducer, similar to the driver in a loudspeaker, to create vibrations in a large plate of sheet metal. The plate's motion is picked up by one or more contact microphones whose output is an audio signal which may be added to the original "dry" signal. Plate reverb was introduced in the late 1950s by Elektromesstechnik with the EMT 140. Spring reverbs, introduced by Bell Labs, use a set of springs mounted inside a box. They work similarly to plate reverb, with a transducer and pickup placed at either end of the spring. They were popular in the 1960s, and were first used by the Hammond company to add reverb to Hammond organs. They became popular with guitarists, including surf musicians such as Dick Dale, as they could easily be built into guitar amplifiers. They were also used by dub reggae musicians such as King Tubby.