Mod Squad: Soundmachines LP1lightplane

Use this gestural controller to shape sounds with your finger, then loop them

Vertical and horizontal LEDs show the x and y position of your finger, while the LED in the corner indicates when the gate is on. The lights behind the capacitive Rec and Hold buttons show which of the three performance modes you are in. The z axis, pressure, is not indicated with LEDs. GESTURAL CONTROLLERS are an important part of any performance instrument, and modular systems are no exception. Using a capacitive touch-surface, the Soundmachines LP1lightplane ($160 street) generates control voltages based on the position of your finger in three dimensions—x, y, and z (pressure)—as well as a gate signal when touched. Meanwhile, an integrated microcontroller provides modern, performance-oriented features that make this module stand out among its peers.

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The LP1 is very light and skiff-compatible because the front panel is also the main circuit board; all components are attached underneath. To fit your playing needs, the LP1 can be positioned with the outputs at the top or bottom. A jumper on the back matches the touchpad’s behavior to the orientation of the module. Jumpers also independently set the range of each CV output (0-5V or 0-10V), and whether the gate jack sends or receives a signal. (More on this shortly.)

The z axis, pressure, is determined by the amount of skin contact on the panel: As you press harder, the surface area of your finger spreads out, and the microcontroller interpolates the values and smoothes the voltage output.

As a digital controller with a 9-bit output DAC, the input resolution of the touch surface (128 points for x/y axes; 32 to z axis) does not offer the fully continuous voltage you’d get from an analog capacitive touch-plate. Consequently, you will hear some stepping and the output can be a little jumpy if your finger moves subtly when you hold a note.

Still, the LP1 isn’t relegated to broad brushstrokes, but provides a surprising amount of subtlety.

A La Mode Even with three performance modes, the LP1 is very easy to use. In Live mode, the module tracks your finger position and sends a gate signal only when you touch the playing surface. Tap the Mode button to enter Hold mode and freeze the x and y CV output levels to the last spot you touched on the matrix. While in Hold mode, the gate stays at full positive value until you return to Live mode, but you retain continuous control over the z-axis voltage level.

The most exciting feature of the LP1 is its ability to immediately loop 4.5 seconds of your performance using the playing surface. To record, touch the Rec button with one finger as you move another finger around the control matrix. As soon as you let go of the Rec button, the module begins repeating the loop. This allows you to draw and repeat custom voltage contours instantly.

You can still play the touchpad while a loop is repeating, although touching the matrix temporarily interrupts the loop. To pause the loop, tap the Hold button, or touch the Rec button again to stop the loop altogether. Unfortunately, you cannot save or recall your looped performances once you stop them.

The controller offers two modes for record/playback resolution—Standard and High Quality. In High Quality mode (the default), the x and y axes and gate are recorded with a sampling resolution of 15 ms, but you forfeit the ability to record the z axis (pressure). Standard mode allows you to record all three axes and gate, but with a lower timing resolution of 30 ms. Switching between modes is as easy as holding the Rec and Hold buttons until the x and y LEDs flash.

If you set the gate jack to accept an external signal, you can use an incoming voltage to trigger the loop from the first sample. It was fun using a VCLFO to restart the loop from different spots in its cycle: I wish the module had a dedicated external-gate input or at least a front-panel switch for the gate jack.

Although there are other touchplates on the market, the LP1’s performance modes, looping feature, and low price make it a must-have for nearly any performance-oriented rig.

(Special thanks to Control Voltage in Portland, Ore., for the review unit.)