# Arcus Audio — Unity Mixer - [Manual PDF](../../manuals/Unity Mixer - Arcus Audio.pdf) --- [Manual PDF](https://arcusaudio.com/product/unity_mixer/) # Arcus Audio Unity Mixer — melodic use analysis The PDF/page provided is for the **Arcus Audio Unity Mixer**, a **2HP dual 3:1 unity gain summing mixer** that can also function as a **single 6:1 mixer**. It is **DC-coupled**, so it can mix both **audio and CV**, which is what makes it especially useful for melodic patching in Eurorack. ## Module identified from the manual ### Unity Mixer - **Type:** Dual 3:1 unity gain mixer / 6:1 mixer - **Width:** 2HP - **DC-coupled:** yes - **Use with:** audio or CV - **Input impedance:** 10kΩ - **Indicators:** bi-color LEDs on outputs 1 and 2 for level/polarity - **Power:** 15mA on +12V, 15mA on -12V --- # What this module does musically A unity mixer does not amplify or attenuate by itself; it **adds signals together at fixed gain**. In melodic systems, that is extremely valuable because melodies often come from **combining pitch-related voltages**: - sequencer pitch CV - keyboard CV - quantizer output - transposition voltage - octave offsets - envelopes used as temporary pitch bends - LFO or vibrato - random voltage - chord intervals Because the Unity Mixer is **DC-coupled**, it can combine all of those control voltages directly. --- # Best melodic uses ## 1. Transposing a sequence Patch: - **Input 1:** pitch sequence CV - **Input 2:** offset voltage from a precision adder, keyboard, fader, or fixed voltage source - **Output:** oscillator 1V/oct Result: - Your melody plays normally, but the second voltage shifts it up or down. - This is one of the simplest and most useful melodic applications. Example: - Sequence sends the melody - A slow manual offset or another sequencer row transposes the entire line every bar --- ## 2. Adding vibrato or pitch animation Patch: - **Input 1:** main pitch CV - **Input 2:** attenuated LFO - **Output:** oscillator pitch input Result: - The oscillator follows the melody, while the LFO adds vibrato. Important note: - Since this mixer is unity gain and has **no attenuators**, the modulation source should already be reduced elsewhere. - If your LFO is too strong, vibrato may become wide pitch wobble. --- ## 3. Creating pitch slides and bends Patch: - **Input 1:** sequencer pitch CV - **Input 2:** envelope or function generator - **Output:** oscillator 1V/oct Result: - The envelope adds a temporary pitch rise or fall at each note. - Great for acid-style attacks, plucks, or expressive bends. This works especially well if the envelope is short and subtle. --- ## 4. Layering interval voltages for harmony Patch: - **Mixer A output:** root melody CV + interval offset - **Mixer B output:** root melody CV + different interval offset Send: - Output A -> oscillator 1 pitch - Output B -> oscillator 2 pitch Result: - You get harmonized melodic lines from one source melody. Example uses: - root + fifth - root + octave - root + third If you have fixed voltage sources or a sequencer channel producing stable interval voltages, this mixer lets you build simple harmonic structures. --- ## 5. Mixing several melodic CV sources before quantization Patch: - **Input 1:** slow random CV - **Input 2:** stepped sequencer row - **Input 3:** manual offset - **Output:** quantizer input Result: - The mixed voltage becomes the raw melodic material. - The quantizer then forces the combined result into a musical scale. This is one of the most powerful uses for a unity mixer in melodic composition: - random provides variation - sequence provides structure - offset provides phrase movement --- ## 6. Mixing after quantization for controlled transposition Patch: - **Input 1:** quantized melody CV - **Input 2:** octave offset or transposition CV - **Output:** oscillator 1V/oct Result: - Keeps the melody stable while allowing phrase-level movement. - Very useful when you want musical transposition without changing the contour of the melody. --- ## 7. Building a 6-input melodic control bus Since the two 3:1 mixers can act as a **single 6:1 mixer**, you can combine many melodic influences into one pitch stream. Possible combined sources: - sequencer - keyboard CV - offset voltage - vibrato LFO - envelope bend - random modulation Result: - One “composite melody CV” controlling an oscillator or quantizer. This is excellent for experimental melodic systems where pitch is generated by several interacting sources. --- # How to use it with common melodic module types Even though the provided PDF only directly documents the Unity Mixer, here is how it fits into a typical melodic Eurorack voice. ## With a sequencer Use the Unity Mixer to: - transpose the sequence - add accents as pitch offsets - combine two rows into one more complex pitch line ## With a quantizer Use the Unity Mixer: - **before quantizer** for generative note creation - **after quantizer** for octave transposition and controlled shifts ## With oscillators Send mixed pitch CV to: - one oscillator for a single animated melody - two oscillators from separate summed outputs for harmonized lines ## With envelopes and LFOs Add: - envelopes for bends - LFOs for vibrato - stepped modulation for melodic ornamentation ## With precision voltage sources Although this is not specifically described as a precision adder in the manual, it can still be used for **practical pitch summing** in many patches. For highly exact long-range 1V/oct transposition, a dedicated precision adder may be better, but for many real-world musical patches this mixer is still very useful. --- # Patch ideas for melodic music ## Patch 1: Simple transposed bassline - Sequencer pitch out -> Unity Mixer input 1 - Manual offset/fixed voltage -> input 2 - Mixer output -> VCO 1V/oct - Sequencer gate -> envelope -> VCA Use: - offset voltage to move the bassline between sections Sound: - classic structured melodic bass part --- ## Patch 2: Lead with vibrato and pitch envelope - Sequencer pitch -> input 1 - attenuated LFO -> input 2 - short envelope -> input 3 - mixer output -> lead oscillator pitch Sound: - stable melody with animated vibrato and slight attack bend --- ## Patch 3: Generative melody source - stepped random -> input 1 - slow triangle LFO -> input 2 - manual offset -> input 3 - mixer output -> quantizer -> oscillator Sound: - evolving but scale-locked melodic line --- ## Patch 4: Two-voice harmony from one sequence **Mixer 1** - root melody -> input 1 - +third offset -> input 2 - output 1 -> oscillator A **Mixer 2** - root melody -> input 1 - +fifth or +octave offset -> input 2 - output 2 -> oscillator B Sound: - instant harmonized melodic texture --- ## Patch 5: Phrase modulation bus Use all 6 inputs: - main sequence - bar-by-bar transpose CV - vibrato - occasional random step voltage - envelope bend - fixed offset Then: - output -> quantizer -> oscillator Sound: - a melody with internal motion and larger-form phrasing --- # Strengths of this module for melodic work - **Tiny 2HP footprint** - **DC-coupled**, so it handles pitch and modulation CV - Can support **two separate melodic voices** - Can be combined into a **single complex melody CV mixer** - LEDs help visualize polarity and signal activity - Great for adding small melodic utilities without sacrificing rack space --- # Limitations to keep in mind ## No attenuators This is the main limitation in melodic patching. If you are mixing pitch CV with LFOs, envelopes, or random voltages, you will often want: - attenuators - offset generators - utility VCAs Without attenuation, modulation depth may be too large. ## Not explicitly presented as a precision adder For very exact pitch transposition across many octaves, a dedicated precision adder is usually safer. But for many melodic and experimental applications, this mixer is still very useful. ## Summing can push voltage ranges high If you combine several CV sources, the total voltage may exceed the musically useful range for the destination. A quantizer or attenuator downstream may help. --- # Overall musical verdict The **Arcus Audio Unity Mixer** is not a melody generator by itself, but it is an extremely useful **melodic utility**. In a Eurorack system, melodic content often comes from **summing multiple control voltages**, and this module is built exactly for that. It is especially good for: - sequence transposition - harmonic interval stacking - adding vibrato or pitch envelopes - combining generative CV sources before a quantizer - making two related melodic voices in minimal space If your rack already has: - a sequencer - quantizer - oscillator - envelopes/LFOs - a few offset or attenuator tools then the Unity Mixer becomes a very effective **melodic glue module**. --- [Generated With Eurorack Processor](https://github.com/nstarke/eurorack-processor)