Harmonic Enhancer

EE 41 November 1988 HARMONIC ENHANCER by W. Teder An harmonic enhancer, or exciter, generates harmonics from, and superimposes these on to, a music signal that has none, or few, of these overtones. In that sense, it is a sound-correcting device that adds warmth to a sound. The principle of the operation of an ex- citer is shown in Fig. 2. Part of the original signal is fed to a variable clip- per, whose cut-off frequency can be set from 1-5 kHz. The filter output, whose amplitude should not exceed 10% of that of the original signal, is then recom- bined with the original signal. The basic set-up in Fig. 2 may be modified and refined in various ways. It is, for instance, possible to make several of the filter parameters adjustable exter- nally, but for most relatively simple needs this sophisticated approach is not really necessary. Moreover, the filter might be preceded by a compressor cir- cuit and followed by an expander circuit. This method obviates the serious distor- tion cau...