Levels
Two settings decide whether the HX Stomp sounds like the demo or sounds broken. Neither of them is a tone control, and both are buried in a menu.
Almost every "it sounds thin", "it sounds quiet", "it sounds harsh" or "it sounds fizzy" report comes down to two settings, and neither is a tone control. One is what you told the box your instrument is. The other is what you told it your speakers are. Get both right and the preset that sounded broken sounds like the demo. Line 6 are blunter about it than usual in this manual: if you go online saying it sounds bad, the first thing anyone will ask is whether you read this section.
HX Stomp 3.80 Owner's ManualFirst, tell it what you plugged the outputs into
Global Settings > Ins/Outs, Knob 2 — Output Level. There is one pair of outputs and one setting, so unlike the bigger Helix boxes you have to pick the destination that matters most. Usually that is whatever the audience hears.
- The Guitar In of a guitar or bass amp
- Inst
- The guitar input of a stompbox or another multi-effect
- Inst
- The instrument-level effects return of an amp — four-cable method, or post effects
- Inst
- The line-level effects return of a guitar or bass amp
- Line
- The inputs of a studio rack effect, or a mixer
- Line
Then tell it what you plugged in
Global Settings > Ins/Outs, Knob 1 — Input Level. This decides whether a hot pickup clips the converter before any modelling happens, which sounds like fizz that no EQ will remove.
- A guitar or bass with passive pickups
- Inst
- A guitar or bass with really loud active pickups
- Inst or Line — trust your ears
- A keyboard, synth, or drum machine
- Line
You do not have to guess whether a level is wrong. The Input and Output blocks in the chain fill green when a signal is present and red when it is too hot. Red means turn something down before that point. Send and Return blocks carry their own clip indicators too, so you can see rather than assume whether the loop is the problem.
The effects loop has the same choice
The Send and Return pair is set to Instrument or Line separately from the main outputs — Instrument for stompboxes in the loop, Line for a rack processor, or for using the pair as extra ins and outs.
Impedance changes feel before it changes level
The Input block carries an In-Z parameter. A lower value rolls off some highs, drops a little gain and feels softer; a higher value is full-range, hotter and tighter. It is loading your pickups the way a real pedal or amp input would, which is why the same preset can feel different with a fuzz in front of it.
Global EQ is for the room, not the preset
Three parametric bands plus low and high cut, sitting after everything. It exists for the day the backline or the room makes every preset too dark or too bright — not for fixing one sound, which belongs in the preset.
Watch the block levels too
One more level worth knowing about: every block has its own Level parameter, and Line 6's advice is to leave it at 0.0 dB on most of them. Nudging three or four in a row is a common way to clip the output while every individual setting still looks reasonable.
Levels are half of it. The other half is the cab block — on into anything full-range, off into anything that ends in a real guitar speaker. Get both right and almost nothing else can make it sound broken.