Two players sharing one G-Force

Together with the page about making an effect loop this trick is a bit of overkill. It's also among the most difficult (programming-wise) on the site, and like any page may contain errors.

Since the G-Force features stereo inputs it can be used as two parallell effect processors, each with its own separate effects. Guitars with stereo pickups can also be processed with separate effects on each side of the stereo image, or you can split the guitar signal with an external stereo effect before it enters the G-Force and process each stereo side independently.

Basic principles

The two input signals can either be mixed together in the G-Force effects or be kept separate. In both cases the G-Force output can be sent to a stereo power amp for stereo effects, or two separate mono power amps.

How to split the stereo signal

Normally the signals from the two G-Force input jacks are sent through one stereo pipeline, but to process them separately they must be split up:

• The Advanced Tremolo can be programmed to block one of its inputs by choosing LFO phase 180 degrees, Depth 100% and Mix 100%, and turning off Speed at the desired pan position (Speed can be turned off from G-Force software version 1.12). Effects routed after the Advanced Tremolo will now only receive signals from one of the input jacks.
• The Dual Delay can both block one of its inputs (by turning down that Delay Line's Level) and pan its output. This means that it can allow say only the right side to enter, yet still pan it hard left at its output. Like the Panners (below) it can also mix its stereo input into mono with the Pan parameters. (If you want to use the Delay block for actual delay effects you can use the Dual Two Tap delay, were each Delay Line features two taps, one of which can be used as a delay, the other for the dry signal. Be aware of its software bugs, though.)
• Stereo input effects never mix the left and right inputs, except for the Dual delays (depending on their Pan positions).
• Mono input effects mix the left and right side into mono when routed directly after the Input section. When another effect is routed between them and the Input section, they instead block their right input and only allow the left stereo side to enter (the Panner is an exception; it always mixes the left and right input into mono).
• The Panners will mix the left and right stereo sides into mono, regardless of where they are routed. This mono signal can then be panned to a fixed position by choosing Speed Off (software version 1.12 and higher). In the Surround Panner a better way might be to choose Speed Off, Width 0%, and adjust Center to a value where it's really centered.

How to pan the split signals to the outputs

Unless you want the two players to share a power amp you must make sure that the signals reach the appropriate output jacks:

• The Delay and Pitch Shift blocks can be used to pan a signal to the desired output jack. The Panners may also be used for this, but in most cases the Panner/Tremolo block is used most effectively when the Advanced Tremolo splits a stereo input signal (see above).
• A signal that's sent through a stereo input effect will retain its panned state. For example, a signal that's panned hard left will stay like that even after passing through a Chorus.
• Since Mono input effects block the right side of a signal you can't use them if you've already blocked the left side. Since they create a stereo signal from a left only input, the signal will reach both G-Force output jacks unless the signal chain ends with an Advanced Tremolo, Delay or Pitch Shift effect where it can be panned to the desired output jack.

External setup

• In I/O Setup > Audio, use the Stereo input option.
• The Input level and the Gate will affect both input jacks. If you want separate settings you can make your own Gate from internal modifiers.
• The Output level and the Speaker filter will also affect both output jacks. You can make two separate speaker filters using Delay or Resonance filters.

Examples

A pipeline normally consists of both a left and right signal. Here I instead use lines of xxxx and oooo characters to indicate left and right input signal flow. A line of xoxo means the left and right input signals are mixed, a + means two lines are crossing.

1. Mixed effects into a common stereo power amp

            _________    _______    _________       _______
 Left xxxxx|Mono in  |xo|Left in|xo|Stereo in|xoxox|       |
       x   |effect   |  |effect |  |effect   | x   |Stereo |
       x oo|_________|  |_______|xo|_________|o+ox |power  |
       x o  _________    _______    _________  x o |amp    |
       xx+x|Stereo in|  |Mono in|xo|Left in  |xo x |       |
         o |effect   |xo|Panner |  |effect   |   o |       |
Right ooooo|_________|  |_______|  |_________|oxoxo|_______|


xxxx = Left input signal
oooo = Right input signal
xoxo = Mixed Left and right input signal
   + = Crossing lines

Here the left/right signal sides are never really separated, instead they are mixed and processed together and finally sent out to a common stereo power amp.

In the top row, the first mono input effect mixes the Left and Right input signals together (because it's routed next to the Input), so even though the following left input effect mutes its right input the signals are already contaminated. (If a stereo input effect was routed directly after the Input and followed by a left input effect, the Right input signal would be blocked.)

2. Separate effects into a common stereo power amp

         _________    _______    _________       _______
 Left xx|Stereo in|xx|Left in|xx|Optional |xoxox|       |
        |effect   |  |effect |  |effect   | o   |Stereo |
        |_________|  |_______|xx|_________|x+xx |power  |
         _________    _______    _________  o x |amp    |
        |Stereo in|  |Dual   |oo|Optional |oo x |       |
        |effect   |  |Delay  |  |effect   |   x |       |
Right oo|_________|oo|_______|  |_________|oooxo|_______|

xxxx = Left input signal
oooo = Right input signal
xoxo = Mixed Left and right input signal
   + = Crossing lines

From the Left input jack the signal passes through a stereo in effect and then enters a left in effect, where the Right input jack signal is muted. From there on you can use any effects you like in the top row, since separating the outputs is not an issue in this example.

From the Right input jack the signal passes through a stereo in effect and then enters the Dual Delay, where the Left input signal is muted while the Right output is panned left. After the Dual Delay you can use any effects you like. (If you only intend to use stereo in effects after, you might use the Advanced Tremolo instead of the Dual delay, which allows you to use the Delay elsewhere).

3. Separate effects into separate mono power amps

         _________    ________    ________    _________    _________
 Left xx|Stereo in|xx|Optional|xx|Advanced|xx|Optional |xx|Left     |
        |effect   |  |left in |  |Tremolo |  |stereo in|  |power amp|
        |_________|  |________|  |________|  |_________|  |_________|
         _________    ________    ________    _________    _________
        |Dual     |oo|Optional|oo|Pitch   |  |Optional |  |Right    |
        |Delay    |  |effects |  |Shift   |  |stereo in|  |power amp|
Right oo|_________|  |________|  |________|oo|_________|oo|_________|

xxxx = Left input signal
oooo = Right input signal

From the Left input jack the signal passes through a stereo in effect and into a left in effect, where the Right input jack signal is blocked. Several left in effects can then be used in series in the top row (each one will block the previous one's right stereo side), but they must be ended with the Advanced Tremolo in order to block the right side of the last one's stereo output (otherwise it will reach the Right output jack). You can still rout a stereo in effect before or after the Advanced Tremolo, since a stereo-in effect will not affect the channel separation in either position.

From the Right input jack the signal enters the Dual Delay, where the left side is blocked. In addition the Dual Delay pans its output signal hard left, so that it can enter any left in effects after. After the Delay you can rout any left- or stereo in effects, but they must end with the Pitch Shifter in order to pan the signal hard right again (so it only reaches the right output jack). If you want you can add stereo after the Pitch Shifter, since they will not affect the channel separation.