4ms Percussion Interface + Expander Eurorack Modules (4+4 HP)

4ms PIEXP MODULE Overview

Convert microphone, instrument, line, and modular signals into CV and clock/gate signals with the 4ms Percussion Interface + Expander, a pair of Eurorack modules capable of generating gate and envelopes from almost any audio source including acoustic drums, samplers, and drum machines.

The Percussion Interface and Expander work well for synchronizing sequencers or other modules to the rhythm of an audio track or live percussion. The modules can simultaneously be used as a preamp for microphone- or line-level signals, while generating inverted envelopes useful for side-chaining. The Expander requires the main PI module and adds three gain stage options, a modular-level audio output jack, a 1/4" input jack, and envelope attenuation capabilities. The PI + PI Expander modules ship with a ribbon power cable and mounting screws.

Percussion Interface and Expander Overview

• Sensitivity knob, Low|Medium|High gain switch, and clipping LED
• Sustain control to prevent misfires, increase gate length, and control the envelope
• Envelope decay control
• Non-inverted and inverted envelope outputs, useful for side chaining
• Four envelope outputs: two attenuated with independent attenuators, and two non-attenuated
• Envelope following or generation modes
• Gate output for clocking sequencers or any unit with a clock or trigger input
• Compatibility with drums, samplers, microphones, drum machines, etc.
• 1/4" input jack

Percussion Interface Controls and Jacks

• In Jack: Accepts a wide range of signals from microphones directed at acoustic sounds such as drums, electronic drum machines, samplers, guitars, synthesizers, line-level equipment, or any other audio source. With the exception of microphones that require power (phantom-powered and electret microphones), any microphone or piezo transducer will work. The In jack is mono but will work with a stereo or balanced cable.
• Sensitivity Knob and Light: The Sensitivity knob controls how much the input signal is boosted. At maximum gain settings, the smallest input signal that will trigger a gate output is roughly 5 to 10mV. The Sensitivity range is determined by the position of the L|M|H switch on the PI Expander. The light will show blue when a signal is detected and will gradually turn red as the unit begins to clip at the input. Clipping may result in undesired gates or envelopes, also known as misfires.
• Sustain Knob: The Sustain knob controls the pulse width of the gate output as well as the sustain time of the envelope while in Gen. mode. When the gate output is high, no additional triggers will be generated, so misfires can be reduced. The minimum pulse width is 5 ms, and the maximum is 0.5 sec.
• Envelope Decay Knob: The Env. Decay knob sets the decay time of the envelope. The envelope has an exponential curve.
• Follow/Gen. Switch: The Follow/Gen. switch selects between two envelope modes. In Gen. mode, the envelope has a sharp attack, followed by a sustain period and an exponential decay.The attack and sustain period are synchronized with the gate output, that is, the envelope remains high as long as the gate is high. In Follow mode, the envelope responds to the peaks and valleys of the input signal and ignores the gate.
• Gate Out Jack and LED Indicator: The Gate jack outputs a pulse which is generated from the input signal. It can be used to clock sequencers and trigger other modules. When high, the Gate jack outputs 8V, indicated by the white light above the jack.
• Envelope Output Jacks: The top left jack, marked by the + symbol, outputs a 0V to 9V envelope when triggered by the input signal. The blue light above the jack indicates the envelope s level. The jack at the bottom right, indicated by the symbol, outputs an inverted copy of the envelope. When the envelope is at rest, this jack outputs 9V and the green light above the jack is fully bright. When the envelope is triggered, it falls to a minimum of 0V and the green light will dim. This envelope is useful for side-chaining.

Percussion Interface Expander Controls and Jacks

• Env. Level Knob: The Env. Level knob attenuates the signal of the Env Out jack on the PI Expander. When the knob is turned all the way down, the jack will output 0V (no signal). As the knob is turned up, the signal will increase in amplitude to a maximum of 9V.
• Inv. Level Knob: The Inv. Level knob attenuates the inverted envelope signal of the Inv. Out jack. When the knob is turned all the way down, the jack will output 0V (no signal). As the knob is turned up, the signal will increase in amplitude to a maximum of 9V. For example, if the knob is at 50%, the Inv. Out jack will output a steady 4.5V until an envelope is triggered, at which point it will fall to 0V and then decay back to 4.5V.
• Env. Out Jack: The Env. Out jack on the PI Expander outputs an attenuated envelope signal. This jack functions like the + Env. Out jack located on the main percussion Interface module, except that it can be attenuated with the Env. Level knob.
• Inv. Out Jack: The Inv. Out jack outputs an attenuated inverted envelope signal. This jack functions like the - Env. Out jack located on the Percussion Interface module, except that it can be attenuated with the Inv. Level knob.
• Audio Out Jack: The Audio Out jack outputs an amplified version of the input signal. It can be used as a preamp for microphones or other low-level signals to boost them to modular level. The gain/boost amount is determined by the position of the Sensitivity Knob on the Percussion Interface and the L|M|H switch on the PI Expander.
• L|M|H Switch: The L|M|H Switch selects the gain range of the input signal. The L setting corresponds to low gain, the M to medium gain, and the H setting to high gain.
• 1/4" Input Jack: The 1/4 Input jack allows for the use of a mono 1/4 instrument cable. The 1/4 Input jack can only be used when the IN jack on the main PI module is unpatched patching into the main IN jack will disable the 1/4 Input jack. This jack is mono (TS), so only the left channel of a stereo TRS cable, or the + signal of a balanced cable, will be used.

Eurorack Ready

• 4+4 HP Eurorack format modules
• Maximum Depth: 0.98" (25mm)
• Percussion Interface: Includes power ribbon cable with 10-pin Eurorack power header
• PI Expander: Includes 8-pin cable that connects to Percussion Interface module
• Power consumption: +12V: 104mA, -12V: 65mA