Georgius Bernardus Josef Sanders

Hybrid loudspeaker system for converting digital signals to acoustic signals

In a loudspeaker system for converting an n-bit digitized electric signal (6) into an acoustic signal a plurality of sections (voice coils 14.1, 14.2, 14.3, 14.p) of a digital loudspeaker (1) are driven directly by the p most significant bits of the n-bit digitized electric signal (6). The loudspeaker (1) comprises at least one additional section (14.p+1). This (p+1)th voice coil receives a signal from a digital-to-analog converter (5), the input signal of the digital-to-analog converter comprising at least the n-p least significant bits (FIG. 2). In a different embodiment the digital-to-analog converter (5) receives all the n bits of the digitized electric signal as the input signal. At least the p sections (14.1 to 14.p) which correspond to the p most significant bits are provided with means (the resistances r) for producing a signal which is a measure of the sum of their instantaneous drive signals and for applying the said signal to a signal combination unit (32) arranged in the line (10) from the output of the digital-to-analog converter (5) to the (p+1)th section (R1). By means of this correction circuit the distortion in the loudspeaker system can be reduced substantially (FIG. 3b).