To minimize aliasing, it is helpful to use nonlinearities that are
approximated by polynomials of low order. An often-used cubic
nonlinearity is given by 
The cubic nonlinearity, being an odd function, produces only odd harmonics. To break the odd symmetry and bring in some even harmonics, a simple input offset can be used . It was found empirically that a dc blocker  was needed to keep the signal properly centered in the output dynamic range. Since amplifier loudspeakers have a dB/octave low-frequency response, at least two dc blockers are appropriate anyway.
While the cubic nonlinearity is the odd nonlinearity with the least aliasing (thereby minimizing oversampling and guard-filter requirements), it is sometimes criticized as overly weak as a nonlinearity, unless driven into the hard-clipping range where it is no longer bandlimited to three times the input signal bandwidth.