http://www.earthquakerdevices.com/shop/Spatial%20Delivery/cat/13097
The Spatial Delivery is an oddball, a voltage controlled envelope filter that allows you to step outside the universe of funk while reinforcing your secret love affair with auto-wah. It has 3 modes- Up Sweep, Down Sweep and Sample and Hold. With Range, Resonance and Filter controls you can get super emphasized filter sweeps in the Up and Down modes. The Range, in combination with pick attack, controls the sensitivity and reaction time of the envelope and thus the width of the frequency sweep. The higher the Range and harder the attack equals a faster reaction time and higher frequency sweep and vice versa. Reign in the controls a bit, add your favorite overdrive/fuzz after the Spatial Delivery and you've got a real nice resonant, cut-through-the-mix lead tone. Crank the controls back up and you're a neo-bedroom rock god. In the Sample and Hold mode the filter is controlled by random voltage and the Range controls the speed. Add a sub octave into the mix (before or after) and you've just created a deep fried space droid computer freak-out. The filter can be cross faded between high pass (counter clockwise), band pass (center) and low pass (clockwise) for a wide variety of voices. The Resonance control goes from zero to the brink of oscillation and adds more body and ring to the filter voice. We recommend placing the Spatial Delivery first in your signal chain. However, due to its envelope control, experimenting with pairing and signal chain placement can take the potential of the Spatial Delivery even further. Each Spatial Delivery is hand made bit by damn bit in silver studded Akron Ohio.
Controls
Mode Toggle: This toggles between upward sweep, downward sweep or sample and hold.
Range: Adjusts the sensitivity of the envelope in Up and Down mode. In Sample and Hold mode, this controls the speed.
Filter: This crossfades between high pass and low pass filters and allows you to get everything in betwee. High pass is fully counter clockwise, low pass is full clockwise and center is band pass. This is much more useful than a simple switch because it allows you to blend the filters for different sounds!
Resonance: This is the filter feedback control, it adds more body and ring to the filter voice.
Power: Please use a standard 9 volt DC power supply intended for musical instruments with a negative center 2.1mm barrel.
Current Draw: 69ma
(description lifted from EQD website.)