The mixer allows the mono sound produced by each separate virtual CoCo to be routed to a Right or Left channel as is or mixed with another sound source.
The Mixer Outputs are routed to the 3.5 mm jack on the back of the CoCo5 labeled Audio on the CoCo case and labeled "Stereo Audio Out" in the figure above.
The Figure below is a block diagram that outlines Mixer Operation.
The analog inputs i1 and i2 are connected by to two points on Terminal Block like device that accepts a screwed down wire in one side and connects to the iX trace on the other. So for instance you could take a stereo audio wire like the one that would connect an ORC90 to headphones and cut it, separating the Right and Left Chanel signal wires. This would allow an ORC90 cartridge in the internal cartridge slot to route it's audio into the Mixer you only need to connect the Right Channel Wire to i1 and the Left Channel Wire to i2 which would then let you mix the ORC90 sound with whatever is playing on the virtual CoCo's.
To best understand the Mixers capability's lets look at the X prompt commends for mixer configuration.
Mixer configuration commands at X prompt.
X>HRDMAN MIX VOLUME(i1)
= 5
This sets the weight of analog input i1 to 3db
above it's base value see table below for weight values.
X>HRDMAN MIX SHOW
This shows the mixer settings in a system overlay window SHOW is
written in grey because typing it is optional just MIX by itself does
the same thing..
X>HRDMAN MIX IN ="in","in",..
RESET ( MAX | MIN )
This command resets the mixer volume of all inputs to base
values unless "in" is used to specify which inputs if the MAX or
MIN parameters the volume is set to MINIMUM or FULL.
X>HRDMAN MIX IN="in","in"..
OFF
The Mixer cannot be completely shut off but mixer inputs
can be shut off for example MIX i1,i2 OFF would turn off all analog
inputs to the mixer.
X>HRDMAN MIX V
SAVE
This command saves mixer settings to MIX.TXT on /u1 if V
is specified only the Volume settings are changed.
X> HRDMAN MIX V
RESTORE
This command restores the settings from MIX.TXT
if the V option was specified only the volume settings are restored.
Note each of these commands starts with HRDMAN if you are in Dual CoCo mode you can instead use the Tandy code to put CPU#1 which is in Hardware Management mode in Focus that will put the H> at the bottom of the screen. At the H prompt these commands become the following in NOT VERBOSE format.
OK so lets look at the commands again in more detail.
Questions: What is meant by "CPU currently in Focus"?
Calling the CPU currently in Focus X then X becomes in
Focus by using the [TANDY] key which cycles through X= CPU's
3,2,1,0,3... or 0,1,2,3,0... with the [SHIFT] key held down or by
clicking on a Window who's TOP(Foreground) level is owned by
virtual CPU #X with the USB Mouse
The MIX.TXT file is searched for on uD0 by CPU#0 or CPU#1 when a command such as MIX R is issued. This file is either found in the ROOT directory in the case of RSDOS or in the /NVR directory if uD0 is formatted as either the OD-9 /ud0 or the MS-DOS A: drive. An example of the contents of this file is listed below.
MIXER SETTINGS
INPUTS
ANALOG
i1=4
i2=4
DIGITAL
#3=16
#2=16
#1=16
OUTPUTS
LCO=/i1+F
RCO=/i1+F
END
// OPTIONAL COMMENTS.
Some sources for the analog inputs might be an internally mounted ORC90
or Speech N' Sound Pack or perhaps a board interfaced to the advanced
adapter.
One possibility would be to use this connection to add the Texas Instruments SN76489 chip for a Tandy 3 Voice sound comparable system.
In addition to the two standard stereo jack outputs two further outputs
bA and bB are available and require codes in MIX.TXT to enable .
These outputs can provide either stereo sound for one Bluetooth channel or
Mono Sound for both. To implement stereo for both Bluetooth channels
the setting Audio-Tee must be turned on in settings memory in that case b2
gets sent a copy of the audio jack sound.