In this article we're going to be talking about setting up external expression pedals and assigning effects to your expression pedals. Expression pedal based effects are a little bit of a different animal than your standard "set-it-and-forget-it" pedals. The normal effects that come to mind like Volume or Wah pedals are all very popular effects, but ideally anything with incremental parameters can be set, even parameters inside your pedals- Gain, Treble, Pan, etc. For the purposes of this guide, we're going to use a volume pedal as an example.
How they are Assigned
As the volume pedal is an expression based effect, it's automatically assigned to your expression pedal when dropped into your rig right onto the A slot. If you have something expression based in the rig already(whammy, wah, etc.), it should assign volume to the B slot of your expression pedal(switched over by clicking the pedal at the top of it's range, known as the toe switch on any Headrush expression). This can be edited from hardware assign mode if you'd like it to be the primary expression effect, which is achieved by tapping the three dots in the top right and tapping "Hardware Assign" in the menu that pops up.
A note on Advanced Expression
This screen also allows you to create an Advanced Expression based setting, which is a way of setting multiple expression based effects to one pedal setting that all change at the same time. You can set up to 4 effects this way. More on this setting can be found in your manual.
Polarity and Physical Pedal Parameters
From here, the polarity of your pedal should be determined if you're using an external one. Your global settings have a setting which should cover the expression pedal's polarity, but any limitations of range to accommodate the expression pedal's range is going to be set mechanically via the pedal(for example, the M-Audio Expression Pedal has a knob to set the CC range to match the Headrush). Please note that the one caveat to this is that your pedal must support TRS cables to function with the Headrush. That specific instruction is outlined in the labelling of the actual ports of every board's manual in the first few pages as it gives descriptions of everything.
A quick note on the MX5 and the Pedalboard- As these boards already have expression pedals built in, plugging a second expression pedal will only give that external pedal control over the B slot effects. As such, the toe switch on the official Headrush Expression Pedal is to be used with the Gigboard. Likewise when using the Gigboard, any expression pedal that does not have a toe switch built in is going to need an external footswitch, like a tap tempo switch, to change from the A/B slots.
Settings inside the actual effect
Finally the actual volume effect settings are listed by double tapping the volume pedal from your rig screen. Now, to make things easy we've included a preset to cut off the actual floor of the pedal to half range. This is done because some people use the expression pedal strictly as a volume boost to switch from rhythm to lead guitar, and finagling their balance to get themselves back down in the mix can be distracting while playing. However you are free to set the minimum volume to whatever you want it to by tapping the minimum volume field and setting it where you want. From there the only setting left to check is whether you want your volume pedal to be Linear or Logarithmic(Linear Off). Honestly if you're not using volume swells as a performance technique then Linear is fine.