MELT routes its AUX input around the filter core and into both output VCAs by default. The auxiliary signal avoids cutoff, resonance, slope selection, and Core Temperature, yet it still shares MELT’s final level-control stages. That placement supports parallel layering without another output mixer.
The path is most useful when one element must remain intact while related material is filtered. A sine fundamental can preserve low-end weight, a noise burst can sharpen percussion, and an overtone-rich signal can strengthen an attack. Each layer reaches the output without entering the driven filter core.
That routing makes voltage-shaped unfiltered layering possible without consuming a separate VCA and mixer channel. Patch an oscillator into a main input, then send a sine wave at the same fundamental pitch into AUX. You can filter the harmonically rich oscillator while the sine remains unaffected by the cutoff sweep.
Keep the AUX contribution restrained at first. A direct fundamental can dominate after the filtered signal loses upper content, especially when resonance changes its apparent body. Set the filtered voice alone, add AUX slowly, and compare at both open and closed cutoff positions.
Transient layering uses the same path with different control. Send a bright waveform or brief noise source into AUX, then apply a short envelope to the AUX VCA CV input. The unfiltered material appears at the attack while the main signal continues through MELT’s low-pass or band-pass response.
This is a practical extension of MELT’s built-in parallel signal path rather than another audio input with identical behavior. The distinction matters when Core Temperature is high. AUX material does not acquire the filter core’s asymmetric saturation, even though it exits beside the saturated signal.
A second filter can also feed AUX. One path then passes through MELT while the other arrives after its filter core, letting both reach the output VCAs together. Check polarity and level at the blend, since related signals can reinforce or cancel when their processing changes phase.
The AUX knob attenuates the control voltage for that VCA. Patching a cable into AUX VCA CV replaces the normalled voltage, so the external signal now determines when and how far the path opens. The knob sets the influence of that CV rather than acting as a conventional audio-level control.
This behavior explains an apparently silent patch. If AUX passes audio before a CV cable is inserted but disappears afterward, confirm that the connected source is producing positive voltage and that the AUX control is raised. Removing the CV cable should restore the normalled fully open state.
Use a gate when the auxiliary layer should switch firmly with an event. Use an envelope when its level needs an attack or decay contour, such as a short noise snap or slowly introduced sub oscillator. A changing control voltage can also make the unfiltered component move independently from the filtered material.
Remember that AUX then passes through the output VCAs. An envelope closing the low-pass output VCA will also close the AUX contribution routed there. This is useful for keeping the complete voice under one amplitude contour, but it can surprise you when AUX is expected to remain continuous.
That duplication may raise the layer’s combined level or place identical material in two processing chains. It can also weaken the contrast between outputs because both contain the same unfiltered component. Mute one channel during setup so you can identify what the filtered output contributes and what AUX contributes.
Internal jumpers determine which outputs receive AUX. Removing the corresponding jumper prevents the auxiliary signal from reaching that path, allowing a filtered low-pass channel and an AUX-free band-pass channel, or the reverse. Power the Eurorack case down before removing the module or changing an internal connection.
Choose the jumper configuration from the job of each output. Keep AUX on the low-pass side when a sub layer should accompany the main voice, or reserve it for the band-pass side when a gated transient belongs only in that channel. Verify both outputs separately after reinstallation before rebuilding the full mix.
The path is most useful when one element must remain intact while related material is filtered. A sine fundamental can preserve low-end weight, a noise burst can sharpen percussion, and an overtone-rich signal can strengthen an attack. Each layer reaches the output without entering the driven filter core.
AUX remains separate until the output stage
Signals patched into inputs 1, 2, and 3 are summed before the filter. AUX follows another route and joins the signal at the low-pass and band-pass output VCAs. The filtered and auxiliary components therefore remain separate through tone shaping but leave through the same controlled outputs.That routing makes voltage-shaped unfiltered layering possible without consuming a separate VCA and mixer channel. Patch an oscillator into a main input, then send a sine wave at the same fundamental pitch into AUX. You can filter the harmonically rich oscillator while the sine remains unaffected by the cutoff sweep.
Keep the AUX contribution restrained at first. A direct fundamental can dominate after the filtered signal loses upper content, especially when resonance changes its apparent body. Set the filtered voice alone, add AUX slowly, and compare at both open and closed cutoff positions.
Transient layering uses the same path with different control. Send a bright waveform or brief noise source into AUX, then apply a short envelope to the AUX VCA CV input. The unfiltered material appears at the attack while the main signal continues through MELT’s low-pass or band-pass response.
This is a practical extension of MELT’s built-in parallel signal path rather than another audio input with identical behavior. The distinction matters when Core Temperature is high. AUX material does not acquire the filter core’s asymmetric saturation, even though it exits beside the saturated signal.
A second filter can also feed AUX. One path then passes through MELT while the other arrives after its filter core, letting both reach the output VCAs together. Check polarity and level at the blend, since related signals can reinforce or cancel when their processing changes phase.
Normalled voltage changes how the AUX knob behaves
The AUX input includes a dedicated VCA. With no cable connected to its CV socket, an internally normalled 7.5-volt signal holds that VCA fully open. In this state, audio reaches the selected outputs without requiring an external control voltage.The AUX knob attenuates the control voltage for that VCA. Patching a cable into AUX VCA CV replaces the normalled voltage, so the external signal now determines when and how far the path opens. The knob sets the influence of that CV rather than acting as a conventional audio-level control.
This behavior explains an apparently silent patch. If AUX passes audio before a CV cable is inserted but disappears afterward, confirm that the connected source is producing positive voltage and that the AUX control is raised. Removing the CV cable should restore the normalled fully open state.
Use a gate when the auxiliary layer should switch firmly with an event. Use an envelope when its level needs an attack or decay contour, such as a short noise snap or slowly introduced sub oscillator. A changing control voltage can also make the unfiltered component move independently from the filtered material.
Remember that AUX then passes through the output VCAs. An envelope closing the low-pass output VCA will also close the AUX contribution routed there. This is useful for keeping the complete voice under one amplitude contour, but it can surprise you when AUX is expected to remain continuous.
Rear jumpers keep duplicated layers intentional
MELT sends AUX to both the low-pass and band-pass output paths in its default configuration. If you use only one output, that duplication creates no practical conflict. When both outputs feed separate mixer channels, the same AUX layer appears in each unless the routing is changed.That duplication may raise the layer’s combined level or place identical material in two processing chains. It can also weaken the contrast between outputs because both contain the same unfiltered component. Mute one channel during setup so you can identify what the filtered output contributes and what AUX contributes.
Internal jumpers determine which outputs receive AUX. Removing the corresponding jumper prevents the auxiliary signal from reaching that path, allowing a filtered low-pass channel and an AUX-free band-pass channel, or the reverse. Power the Eurorack case down before removing the module or changing an internal connection.
Choose the jumper configuration from the job of each output. Keep AUX on the low-pass side when a sub layer should accompany the main voice, or reserve it for the band-pass side when a gated transient belongs only in that channel. Verify both outputs separately after reinstallation before rebuilding the full mix.
