Three differing forms of distortion, which are associated with low-frequency signals in loudspeakers, are investigated.nIt is shown that distortion due to the Doppler effect can be compared with that due to wow and flutter in recording machines and subjective data obtained for this purpose can be applied to loudspeakers. Generalised design limits for loudspeakers are calculated and it is seen that present BBC designs lie within these limits.nIn loudspeakers designed to reproduce low frequencies, the voice coil is made longer than the magnetic field. At low frequencies, when the amplitude of vibration of the cone exceeds the difference in length, it is shown that instead of the peaks of the wave¬form being clipped, expansion of the input/output curve takes place. This effect, with its associated distortion, can be compensated by employing an appropriate non-linear suspension and thus a much greater useful output can be obtained than by using a linear suspension.
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