The growth and decay of sound in a one‐dimensional room was investigated by using a very special room, namely, a helical spring. Compressional waves in the audiofrequency range were sent down the spring by an electromechanical driver and received at the far end by an electromechanical pickup. Reflection occurred at each terminal, allowing standing waves to be built up. The length of the spring was 30 in. and the transit time was 53.6 milliseconds, giving a propagation velocity of about4612 ft/sec. The 30‐in. spring is thus equivalent to a room about 58 ft long.Oscillograms were obtained for frequencies below 100 cps, showing the discontinuous nature of the reverberation produced in the one‐dimensional room.During the analysis of the oscillograms, Eyring's mechanism of image sources was found to fail to explain some of the oscillograms. A new mechanism was therefore created, called the Two‐Pipe Mechanism, which seems to explain all the oscillograms.The Two‐Pipe Mechanism clarifies: (1) the behavior of a normal mode when decay is started before steady state has been reached; (2) the growth and decay of standing waves on a violin string, by demonstrating the quantized envelope‐levels which control this growth and decay; (3) the growth and decay of non‐normal modes, by showing how decay can consist of the steady‐state frequency alone, even though this is a “not‐allowed” frequency.