Ct1745 Mixer; Features - Creative SB0350 Programming Manual

4-10 Mixer Chip Programming

CT1745 Mixer

This section describes the features and register functions of the CT1745 mixer chip
used on the Sound Blaster 16.

Features

The features of CT1745 have been greatly enhanced from CT1345 Mixer.
Volume Control
CT1745 provides independent 32-level volume control of both stereo channels for the
Master, Voice, MIDI, CD and Line-In sources.
The Microphone source is mono and has 32-levels of volume control.
The PC Speaker source is mono and has 4-levels of volume control.
Output Mixing Control
The output mixing path takes signals from the PC Speaker, Voice, MIDI, Mic, CD
or Line-In sources. On the CT1345, the only way of silencing a source (aside from
terminating the source activity) is to turn the source volume down to zero. On the
CT1745, three of the sources (Mic, CD and Line-In) can be silenced by toggling some
mixer switches to cut off these three sources from the output mixing path.
Input Mixing Control
In contrast to CT1345 which only allows single-source recording, CT1745 supports
recording from the Mic, CD, Line-In, and MIDI sources concurrently. Just as for
Output Mixing Control, it is also possible to disconnect all four sources from the
mixing path.
One novel feature of CT1745 is that it allows you to direct the left and/or right
channels of the stereo sources to the left and/or right channels of the input mixer.
Before making a recording, for example, you can direct the left CD channel to the
input mixer's right channel, and the right CD channel to the input mixer's left
channel. This way, you get left/right stereo reversal at the hardware level.