F_MX

F_MX — 8+1 Stereo Utility Mixer

Overview
F_MX is a compact utility mixer for Voltage Modular with eight input channels and one master output stage. Each of the first eight channels accepts mono or stereo audio, provides its own level control, pan control, mute, solo, and a dedicated pan CV input. Every channel also has its own direct stereo output pair, so F_MX can be used both as a submixer and as a signal router. The ninth row acts as the master mix stage: it receives the summed result of channels 1–8, applies master level and master pan, and sends the final stereo mix to the main output pair.

Signal Flow
Channels 1–8 are the actual input channels. Each channel has a left audio input, a right audio input, a pan CV input, and a left/right direct output pair. The signal from each channel is first interpreted as mono or stereo depending on which jacks are connected, then processed by the channel pan setting and its pan CV input, then scaled by the channel volume control and mute/solo state, and finally sent to both the channel’s own direct outputs and the internal master summing bus. The master stage then sums all active channels, applies the master pan and master volume, and sends the result to the final OUTL and OUTR pair on the bottom row.

Channel Structure
Rows 1–8 all work in the same way. Each row contains two audio inputs on the left side, one pan CV input near the center, a volume knob, a pan knob, solo and mute buttons, and a stereo output pair on the right side. This makes every channel independent and immediately patchable. You can use the direct outputs as post-channel outputs while still feeding the master bus at the same time.

Mono and Stereo Input Behavior
If both left and right input jacks of a channel are connected, F_MX treats the signal as stereo. If only one of the two audio inputs is connected, that single signal is copied internally to both sides before panning, so the channel behaves like a mono source. This is useful when you want to place a mono oscillator, drum voice, or modulation-derived audio signal somewhere in the stereo field without needing an external mono-to-stereo utility.

Volume Controls
The white knobs are the level controls. On channels 1–8, the volume range goes from 0.0 to 2.0, with a default of 1.0. That means each channel can be fully muted, kept at unity gain, or boosted up to double level. The master channel also has a volume control, but its default is lower, set to 0.5. This gives the full mixer some headroom at startup and helps avoid accidental overload when many channels are summed together.

Pan Controls
The yellow knobs set pan position. Their range is 0.0 to 1.0, where 0.0 is full left, 1.0 is full right, and 0.5 is the center position. Pan is implemented as a simple linear balance-style control. For mono sources, this behaves like straightforward left/right placement. For stereo sources, it scales the existing left and right sides rather than cross-mixing them, so it behaves more like narrowing, weighting, or rebalancing the stereo signal than a full stereo imaging processor.

Pan CV Inputs
Every channel, including the master stage, has a PAN input. This input modulates the corresponding pan knob. The incoming CV is scaled internally by dividing by 5, so a ±5V signal becomes approximately ±1.0 pan offset before clamping. The final pan value is always limited to the valid 0.0–1.0 range. In practice this means you can animate channel placement with LFOs, envelopes, random voltages, or sequencer lanes. Because the pan CV is added directly to the knob setting, the knob acts as the base position and the CV acts as an offset around that base.

Mute
Each channel has a green M button for mute. When mute is active, that channel’s gain is reduced to zero. The master stage also has its own mute button, which silences the final summed output without changing the state of the individual channels.

Solo
Channels 1–8 include a yellow S button for solo. Solo works globally across the eight input channels. If one or more solo buttons are active, only those soloed channels are heard in the mix and all non-soloed input channels are suppressed. The master row does not include a solo button, because it is the summed destination rather than a source channel.

Direct Outputs
Each of the first eight channels has its own OUTL and OUTR pair. These outputs carry the channel signal after pan, volume, mute, and solo processing. This is useful when you want to feed separate effects, parallel processors, recorders, or additional mixers while still keeping the signal inside the master mix. In other words, F_MX is not just a final mixer; it can also serve as a patching hub and signal distribution point.

Master Stage
The ninth row is the master section. It does not accept audio inputs of its own. Instead, it receives the summed output of channels 1–8 internally. It has its own pan knob, volume knob, mute switch, pan CV input, and final stereo outputs. This lets you shape the complete mix after all channels have been combined. Because the master stage is separate, you can control the overall stereo position and level of the full submix with a single set of controls.

Important Behavior Notes
F_MX is intentionally simple and direct. It does not include EQ, aux sends, channel meters, clipping protection, or constant-power panning. Pan is linear, and channel boosts can go above unity, so it is possible to overload downstream modules if many hot channels are summed together. Keep an eye on gain staging, especially when using the 2x channel boost range. Also note that solo affects only channels 1–8, not the master stage itself.

Typical Uses
Use F_MX as a compact stereo line mixer for oscillators, drum voices, sample players, and effects returns. Use the direct outputs to split channels into separate processing paths while still keeping a central submix. Use the pan CV inputs to animate stereo movement across multiple channels. Use the master row as a final submixer before feeding a larger mixer, recorder, limiter, or output module.

Control Summary
Channels 1–8: stereo audio input pair, pan CV input, level, pan, solo, mute, stereo direct outputs. Master channel: master pan CV input, master level, master pan, master mute, final stereo outputs.

In Short
F_MX is an 8-channel stereo utility mixer with per-channel routing and a dedicated master bus. It is built for fast patching, simple control, CV-driven stereo movement, and practical modular mixing without extra complexity.