Intended for electric bass, the Soundblox Pro Bass Envelope Filter from Source Audio provides 22 different envelope filter effects, giving you 2-pole and 4-pole low-pass options, as well as single peak filters, triple peak, peak/notch, and a few phasers to boot. These effects have their analog equivalents and inspirations, such as the 3Leaf Audio Groove Regulator and the Pigtronix EP-1. Nevertheless, as is the case with many Source Audio pedals, the emulated hardware is merely a jumping-off point, as a slew of controls are offered to encourage much in the way of experimentation. For instance, in addition to knobs affecting the sweep range, attack/decay speed, and center frequency, you’ll find loads of secondary controls over LFO shapes, Q levels, customized expression pedal routing, and more. Combine the level of control with a seven-band equalizer and six user-assignable presets, and you’ll find yourself with a very flexible effects processor indeed.

Note that there are multiple methods for controlling effects, including an envelope follower, a low-frequency oscillator (complete with tap tempo option), or various types of external control. For example, you can plug an expression pedal into its TRS input to manipulate filters as you would a wah pedal. You can also manipulate various secondary functions externally. MIDI control is also possible via a standard 5-pin DIN connection.

Then you have a quirky method of manipulation sure to pique an adventurous bass player’s fancy: Hot Hand control. The Hot Hand technology provided by Source Audio lets you smoothly control parameters of the pedal through its onboard sensor and a corresponding two-axis accelerometer that you can wear like a ring. In essence, by changing the position of your hand, you can modulate parameters of the pedal in a fluid fashion. A calibration button allows you to find a “zero point,” while an additional sensor is built into the pedal to facilitate the daisy-chaining of other Hot Hand enabled pedals, giving you one ring to rule them all (your pedals, that is).

All the effects are achieved digitally, via the pedal’s 56-bit DSP architecture, and utilizing 24-bit conversion stages at the AD and DA stages to preserve signal integrity as your audio travels through the pedal. A 9 VDC power supply is provided with the unit.