The 2hp Arp is a gate-driven arpeggiator that turns a selected chord into a stepped V/Oct melodic sequence. It’s very compact, but musically it can do a lot: chord-based riffs, repeating ostinatos, pseudo-basslines, harmonic motion, and generative melody when paired with clocks, gates, modulation, and quantized pitch destinations.
At its core, Arp outputs pitch CV based on:
Threshold: 0.4V
Reset Input
Threshold: 0.4V
Root Knob
Sets the base pitch / chord root
Root CV Input
Range: 0V to +5V
Chord Knob
Selects chord type
Chord CV Input
Range: 0V to +5V
Mode Knob
Selects playback direction/order
Output
The module can arpeggiate these chord qualities:
This makes it much more than a simple “up/down notes” utility — it’s really a harmony-to-melody converter.
Playback modes include:
These modes strongly affect the melodic character:
This is the most direct use.
Each trigger advances to the next note in the chosen chord, creating a melodic line that stays harmonically coherent.
The Reset input is one of the most important features musically.
The arp restarts on the root at regular intervals, producing a repeating phrase instead of endlessly drifting.
Without reset, the pattern may feel more circular or continuous.
With reset, it becomes more song-like:
- downbeats land on root notes
- phrases become easier to hear
- basslines feel more intentional
This is especially strong in: - techno - trance - arpeggiated pop lines - sequenced ambient
The Root CV input lets you transpose the entire arpeggio.
The arpeggio pattern stays structurally similar, but shifts to new tonal centers.
Send stepped voltages to Root CV corresponding to: - I - vi - IV - V
Then set the chord quality manually or by CV.
This gives you a complete harmonic progression generator with only a few signals.
The Chord CV Input is where things get especially interesting.
The chord quality changes while the note stepping continues.
For musical results, clock chord changes at slower divisions: - note changes every 16th - chord changes every bar or half-bar
This creates a strong hierarchy: - fast motion = melody - slow motion = harmony
This is where Arp becomes a compact composition tool.
You get a melody that reflects: - harmonic root movement - chord quality changes - pattern direction - octave span
This is enough to generate: - evolving arpeggiated hooks - soundtrack patterns - melodic techno motifs - generative tonal lines
The manual only covers the Arp itself, but musically, here’s how it works with common module types.
A clock or trigger sequencer is essential because Arp is gate-driven.
Use: - master clocks - trigger sequencers - Euclidean triggers - clock dividers/multipliers - manual gate buttons
The timing source determines: - note density - groove - syncopation - phrasing
A rigid clock gives machine-like precision.
Irregular trigger sources give broken, human, or generative melodies.
Arp outputs pitch CV only, so it needs a sound source.
Good destinations: - analog VCO - wavetable oscillator - FM voice - pluck voice - physical modeling voice - any full synth voice with V/Oct input
Different voices change the role of the arp: - sine/triangle = bass or minimal melody - saw/pulse = classic synth arps - wavetable = modern animated sequences - FM = metallic/cinematic patterns
To hear discrete notes, patch triggers to an envelope and VCA.
Each pitch step becomes an articulated note.
Use a different rhythmic trigger for the envelope than for the arp advance: - arp moves on every 16th - envelope opens only on selected steps
This creates implied melodies and rhythmic variation.
If you patch the voice through a filter, you can make the melodic line feel more expressive.
The harmony may stay constant while timbre adds motion, making the arp more musical and less static.
Sequencers pair beautifully with Arp, especially if you use them not for direct pitch, but for meta-control.
Use a sequencer to control: - Root CV - Chord CV - Mode changes via manual performance between takes - resets and phrase length
Instead of sequencing every note directly, you sequence the rules that generate the notes.
That gives: - coherent tonal output - less programming - more happy accidents
These are great for generative work.
A self-moving melodic network that still sounds harmonically structured because Arp constrains note choices to chord tones.
This is one of the best uses of the module:
randomness with harmonic containment.
You may not always need a quantizer after Arp, since it already outputs pitch in a structured harmonic system. But quantizers can still help upstream or downstream.
This helps keep chord roots aligned to a chosen scale or song key.
A precision adder is very useful if you want to transpose the arp while preserving interval relationships.
Sound: tight, classic, musical arp line
Sound: repeating bass figure that follows a progression
Sound: evolving melodic fragments with harmonic identity
Sound: unresolved, floating melodic texture great for intros and breakdowns
Sound: ominous, unstable, tension-heavy melodic movement
If you manually or rhythmically fire reset at section starts, the pattern feels intentional and anchored.
The Chord knob is performance-friendly. Sweeping between major, minor, suspended, augmented, and 7th-based chords can dramatically change mood without repatching.
Even with the same root and chord: - Ascending = verse energy - Pendulum = flowing bridge - Random = breakdown or ambient section - Two-octave = lift or climax
Fast note triggers with slow root/chord modulation give a musically readable hierarchy.
Mult the Arp output to: - a bass voice - a higher pluck voice - a delayed or reverb-heavy texture
If transposed or timbrally separated, one arp stream can become a complete melodic stack.
That means it plays in a fairly standard Eurorack pitch space and should work well with most V/Oct inputs.
So standard Eurorack triggers and gates should work fine.
Very easy to fit into a small system, especially if you want a compact melodic utility.
The 2hp Arp is best thought of as a melodic engine rather than just an effect or helper module. It works especially well when combined with:
Its strength is that it creates melodies that are: - rhythmically driven - harmonically constrained - easy to transpose - compact to patch - performable in real time
So if you want musical melodic content quickly, this module is excellent for: - arpeggios - ostinatos - basslines - harmonic motifs - generative tonal melodies