rdq-6 instruction manual
z-systems audio laboratories
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most significant bits (MSBs) of the DAC. Roughly speaking, attenuating the signal
corresponds to “shifting the bits” to the right. Those against digital volume control would
argue that the loss of resolution begins to happen when the least significant bit (LSB) of the
CD data “slides” past the LSB of the DAC; we call this condition underflow. In the early days of
digital, when 16-bit DACs were the norm, even the smallest amount of attenuation could
cause the data to underflow the DAC. Today, with 20-bit DACs in common use, up to 24 dB of
attenuation can be made without DAC underflow. And, as the dither discussion illustrates,
resolution well beyond the LSB is possible; we typically claim a number of 12 dB beyond the
LSB. This “extension” beyond the LSB, in conjunction with the 20-bit DAC, allows for a full 36
dB of attenuation before any loss of resolution begins to occur. This is a significant amount of
attenuation. With a 24-bit DAC, a full 60 dB of attenuation is possible without any loss of
resolution.
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IGURE
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