shift). This bit shift is implemented differently between module generations. In first-generation modules, this bit shift is performed at the connection between the data bus and DAC: Original (non-shifted) data bit # Connection -------------------------------------------------------------------------------- 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 Output of LA32 synthesizer chip 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 Input to reverberation chip 15 13 12 11 10 09 08 07 06 05 04 03 02 01 00—input to DAC | | | +- most significant data-carrying bit +- sign bit This means that the reverberation chip will not "see" the overflow noise and thus not reverberate it. However, since bit 14 is dropped completely, the effective resolution is reduced to 15 bits, and since the DAC's least significant bit is not connected at all and thus not changing with the sign, additional one-bit noise is produced, audible at low signal levels. In second-generation modules, the bit shift is performed at the connection between the LA32 sound generation chip and the data bus: Original (non-shifted) data bit # Connection -------------------------------------------------------------------------------- 15 13 12 11 10 09 08 07 06 05 04 03 02 01 00 14 output of LA32 synthesizer chip 15 13 12 11 10 09 08 07 06 05 04 03 02 01 00 14 input to reverberation chip 15 13 12 11 10 09 08 07 06 05 04 03 02 01 00 14 input to DAC | | | +- most significant data-carrying bit +- sign bit This means that the reverberation chip will "see" the overflow noise and thus reverberate it. However, since the DAC's least significant bit is connected and does change with the sign, the sound quality is improved slightly over the earlier implementation. To prevent digital signal overflow and its audible result, the digital output volume must be kept low enough so that bit 14 will never be used. On the first generation MT-32, this can simply be done by selecting a lower main volume on the unit's front panel, which directly controls the software main volume setting, which in turn directly translates into the amplitude of the digital output signal. On later generation units, this does not work, as the main volume knob and the software main volume setting only modify the volume of the analogue output using voltage-controlled