All hidden functions of the six-trak can be accessed thru key combinations:

Control record/select 0: dump current sequences and stacks
Control record/select 1: enable/disable program change
Control record/select 2: dump current program (sysex)
Control record/select 3: center pitch wheel (for service use only)
Control record/select 4: enable/disable wheels and parameters
Control record/select 5: ??Control record/select
Control record/select 6: manual tune
Control record/select 7: Zero DAC (for service use only)
Control record/select 8: Basic patch
Control record/select 9: Tune test toggle (for service use only)

Track record/select 0: ??
Track record/select 1: Mode 1, omni on/mono off
Track record/select 2: Mode 2, double mode
Track record/select 3: Mode 3, omni off/mono off
Track record/select 4: Mode 4, omni off/mono on
Track record/select 5: ?? shows the revision number on the display
Track record/select 6: ?? saves the base channel (parameter 36)
Track record/select 7: Local on (enable keyboard)
Track record/select 8: Local off (disable keyboard)
Track record/select 9: dump 100 programs

Track record+Control record/select 0: Erase all sequences


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                        SCI 6TRAK MODE NOTES

The 610 powers-up in Omni Mode (Mode 1).  The Channel Number can
be changed from the front panel (see Parameter 36. under CODED
FUNCTIONS).  The Channel Number is ignored while in Omni On Mode,
except for the Omni Off command.  Mono On commands are ignored in
Omni On rnode (i.e., Mode 2 is not recognized).  On power-up,
only Note On/0ff and Program Dump messages are sent and received.
Wheel changes and program changes can be enabled from the front
panel (see CODED FUNCTIONS).

When Omni Off is selected (Mode 3), all messages without the
Basic Channel number are ignored.

When Omni Off and Mono On (Mode 4), the 6;0 will assign one each
of its six voices to channels N to N+5, where N is the current
basic channel.  Note that this will normally mean channels 3 - 8
(n = 2 - 7).  Note also that the basic channel must not be set
above 11, to allow room for six voices.  When Mode 4 is selected,
it will automatically be set to 11 if the channel is higher.

If Omni On is selected while Mono is On, Poly On/Mono Off will
automatically be executed.

Basic Channel number can be changed by selecting PARAMETER #36,
and adjusting for a value for 1 - 16.  The channel number is
non-volatile--it will remain as selected even through power off.
The Basic Channel is set to 3 at the factory.

Note that the Basic Channel number is sent with transmitted data.

CODED MIDI FUNCTIONS

While holding the RECORD switches, press the indicated SELECT
switch.  CONTROL RECORD is on the right.  TRACK RECORD is on the
left.

                             Modes

Mode l--Omni On/Mono Off TRACK RECORD/SELECT 1

Mode 3--0mni off/Mono Off TRACK RECORD/SELECT 3

Mode 4--0mni Off/Mono On TRACK RECORD/SELECT 4

                             Dumps 
Dump Current Sequences and Stacks 
CONTROL RECORD/SELECT 0.

Dump Current Program 
CONTROL RECORD/SELECT 2. 
This sends 16 bytes of the program data of the program currently
displayed.

Dump 100 Programs 
TRACK RECORD/SELECT 9.

                        Control Options 
Change Channel #
Select PARAMETER #36. Switch VALUE on and adjust VALUE knob to
select desired channel (l - 16). Note that in Mode 4, channel 11
is the maximum usable channel. Channel number can also be changed
remotely by a Select Double Mode command over MIDI.

Select Double Mode 
TRACK RECORD/SELECT 2.
For 610/610 or 610/210. In the master instrument, enables wheel
changes, voice-to- voice program changes and note information
(Mode 4). Selects Channel 11 if set to higher. Sends SYS EX 7B
Double Mode Command to slave, to effect similar changes.

Select MIDI Clock Input 
Turn SPEED knob fully counterclockwise.

Enable/Disable Program Change 
CONTROL RECORD/SELECT 1. 
This toggles Program Change over MIDI, send and receive. On
power-up, Program Change is disabled.

Enable/Disable Wheels and Parameter Changes 
CONTROL RECORD/SELECT 4. 
This toggles PITCH and MOD wheel send/receive and Parameter
changes (receive only) over MIDI. On power-up, disabled.

Local On 
TRACK RECORD/SELECT 7. 
Enables the 610's keyboard, switches, and wheels. Enabled on
power-up.

Local Off 
TRACK RECORD/SELECT 8. 
Disconnects the keyboard, wheels, and switches from the
sound-generating circuitry. The information will be sent over
MIDI, but only MIDI received data will play the 610. This code
will be ignored when the sequencer, arpeggiator, or stack mode is
on.


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- Set parameter #36 to your base MIDI channel.Multitimbral operation
- Hold Track Record and press Select-2.  This will
  put the Six-Trak into multitimbral mode and will respond to
  program change and controllers.  There's a sysex string you
  can send to do this too.  Also, if you send MIDI mode 4
  (omni off, mono) it should also do it.
- Send program changes on channels base to base+5.
- Caveats: multitibral mode is MONO only.  Also, while multitimbral
  mode is in effect, playing on the six-trak keyboard is confusing, 
  because each key is associated with a different patch.  I wish there
  was a way to set the keyboard patch and channel number for recording
  into a sequencer.  The best way to record one track while in
  multitimbral is by using another keyboard as the controller.  Use
  MIDI thru on your sequencer or set up your MIDI patch bay to do this.
Monotimbral operation
- The easiest way to do single timbre is to send omni off, poly on from
  the sequencer.  Otherwise there's a Record+number key combo that will
  do it for you.  I don't know which one offhand, check TFM.
  
  
Ok, I was spacing.  Now that I'm at home with the manual, here's
the deal.  SysEx can be used for program dumps (where all the
parameters for a program are encoded in 16 bytes).  Parameter
changes (aka continous controller) ARE supported -- each
parameter change message will change one parameter on one
channel.  So it seems feasible to do on-the-fly edits.
To select "double mode" via the keyboard, use track record/select 2.
The multitimbral info is given on page 8 and 9 of the MIDI section.


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> >Yes, you can put the Sixtrak into MIDI Mode 4 where it will spread its
> >6 voices across 6 MIDI channels, starting from the basic channel (the
> >current one). However, it is monophonic per channel.> 
> This is apparently not documented in the manual in a clear fashion, 
> according to someone who has one and has been trying to do this. Could
> you provide a pointer to exactly how to set it up, as a public service?
The manual is not real clear about it, that's for sure.  You need to
"Select Double Mode", either from the Keypad (Record + something) or via
SysEx.  This will set up MIDI Mode 4, enable program change, enable wheels,
and set up Mono multitimbral for the channels "basic" to "basic+5".
The basic channel is set up via parameter 36.  Then send program changes
on the 6 channels to set up your patches.
> I strongly doubt this. In 1984, SysEx was terra incognita for most
> manufacturers. I have racked my brains to try to remember if Sequential
> had implemented sysex parameter editing or access for the SixTrak, and
The SysEx implementation is pretty minimal, no parameter changes, but
patch dumps are supported.  It looks possible to do editing on the
fly via parameter change commands but this would be pretty tricky since
each parameter change command changes all the parameters, and the ones
you want are encoded in a few bits.