Everything DeltaComp does.

1 · What DeltaComp is

DeltaComp is a transparent, everyday compressor built on one idea: you should see what a compressor does, not imagine it. The scope scrolls your signal before compression, the signal after it, and draws the difference between them as a coloured band — every dB the compressor removed (or added back), on your material, in real time.

Because the dry reference is tapped inside the plugin, none of this needs any special routing. Drop it on an insert like any compressor — the honest picture comes free.

2 · Install & formats

DeltaComp is currently built as VST3; AU and CLAP are on the roadmap. The installer places the VST3 in C:\Program Files\Common Files\VST3 — rescan plugins in your DAW.

Beta builds are unsigned — Windows SmartScreen will show "Windows protected your PC" → More info → Run anyway. Expected for a beta.

3 · Quick start

1. Insert DeltaComp on a track — no sidechain routing needed for the display.
2. Play the track. The scope fills: the coloured body is your input, the teal core is the output, and the magenta band between them is the gain reduction.
3. Drag the THRESH chip down until the band appears on the moments you want controlled.
4. Drag ATTACK and watch the transient survive (or not) at the left edge of each dip. Drag RELEASE and watch the recovery tail.
5. Enable AUTO (auto-makeup) and A/B with BYP — level-matched, so you judge the compression, not the volume change.

4 · The interface at a glance

5 · Reading the scope

The scope is a scrolling level-over-time picture, 0 dB at the top, −42 dB at the bottom:

• The coloured body is the dry input envelope (its colour follows the channel lane — gold for Stereo, green/amber for L/R, teal/magenta for M/S).
• The teal core inside it is the wet output — what actually leaves the plugin.
• The band between them is the compressor's work: magenta = level removed, green = level added (makeup or parallel blend lifting the signal above the input).

Attack quality lives at the left edge of each magenta dip — a surviving transient pokes through before the band clamps. Release lives in the tail — a band that lets go too fast pumps, one that holds too long ducks the next hit.

Time window: drag the scope's left edge up/down to zoom between 1 s and 15 s of history; double-click it to reset to 8 s.

6 · The compressor controls

Every control is a chip — drag it vertically to change the value (time-based chips drag exponentially, so fine values stay fine), double-click to reset to the default. All chips are host-automatable parameters.

Output Gain (−24 … +24 dB) exists as a host-automatable parameter for final trim; it currently has no on-screen control.

7 · Channel modes

The channel switcher offers Stereo · L/R · L · R · M/S · M · S. This is DeltaComp's superpower: each domain keeps its own full parameter set — threshold, ratio, knee, timing, makeup and mix per lane.

• Stereo — one linked core, one lane. Classic.
• L/R — two independent cores, two stacked lanes (green = Left, amber = Right). Tame a one-sided element without touching the other half.
• M/S — Mid and Side compressed separately (teal = Mid, magenta = Side). Glue the centre, let the width breathe.
• L · R · M · S — solo variants: only the soloed channel is compressed; the other passes through untouched (marked THRU) and is recombined. Solo isolates processing, it never mutes.

8 · Detector & timing

• PK / RMS — the detector character. PK reacts to peaks (grabs transients), RMS averages ~10 ms (rides the body — smoother, more musical on sustained material).
• A.REL — auto release. Program-dependent: the release stretches (up to ~3×) as reduction gets deeper, so loud passages don't pump and quiet tails recover naturally. Your RELEASE chip sets the base speed.

9 · Sidechain & ducking

Two independent tools that combine:

• SC — switch the detector to the external sidechain input. Route a key signal (e.g. the kick) to DeltaComp's sidechain bus, enable SC, and the compressor ducks the track in response to the key. The gain always acts on the main audio; the scope shows the duck as it lands.
• LC · OFF · HC — the permanent detector filter. It shapes what the detector hears — never the audio. LC (low cut) keeps rumble and kick energy from pumping the whole mix; HC (high cut) keeps hi-hat spill out of the decisions. When active, an SC LC / SC HC chip appears for the cutoff (20 Hz … 20 kHz, default 120 Hz). Works on the internal detector too — you don't need an external key to use it.

10 · Monitor — DRY · Δ · WET

• Click the Δ logo (top right) to flip between WET and Δ instantly.
• MONO — collapse L/R to check mono compatibility.
• AUTO — auto-makeup: continuously level-matches the WET output to the dry signal's loudness (a slow ~0.4 s glide). With AUTO on, bypassing compares compression, not volume — louder can no longer masquerade as better. Δ and DRY stay honest (un-matched).
• BYP — true bypass, for exactly that comparison.

11 · Meters & readouts

The readout card (bottom-left)

• Current GR — the big number: reduction right now (magenta), or net lift (green).
• peak — the deepest reduction held since the last reset.
• makeup — total gain added back: your MAKEUP chip plus whatever AUTO is contributing.
• crest — dry → wet crest factor: exactly how much punch the compression traded for density, as a number.

The rails (right edge)

• GR meter — reduction downward from 0, with a held-max cap line. Double-click resets the held max (a single click is deliberately inert, so inspecting never wipes your measurement).
• Frequency rail — a thin per-frequency strip: magenta where the compressor is cutting a band, green where it's lifting one. Compression is never broadband-neutral; this shows where it leans.
• Loudness rail — wet L/R bars with peak-hold caps (optionally a dimmed dry mirror — see Settings). Hover anywhere on it to read the exact dB at your cursor.

12 · Presets

The centre-top bar is the house preset browser: ‹ › step alphabetically through your presets, clicking the name opens the menu — every preset, plus Save As… · Overwrite · Rename… · Delete… · Reveal presets folder. Presets are plain files in Documents\DeltaComp\Presets — share them, back them up, rename them in the file manager. A preset stores the sound (all parameters), not the window layout.

13 · Settings

The ⚙ cog (bottom-right) opens the settings flyout:

• GPU rendering — draws the scope on the GPU (default on). Turn off only on problem drivers.
• 60 FPS refresh — smoother scroll at slightly higher CPU (default 30 fps).
• Loudness meter — show/hide the right rail, plus its dry mirror and dB scale sub-options.
• Shading / Flat shading — the scope's fill intensity and gradient look.

ZEN (bottom-left icon) hides all chrome for a clean, full-canvas scope — same scope, no controls. Click again to come back.

14 · Interaction cheat-sheet

15 · Troubleshooting

• SC is on but nothing ducks. The sidechain bus isn't routed in your DAW — SC switches the detector to the external input, so it needs a key signal arriving on DeltaComp's sidechain. Route one (per your host's sidechain routing) and the duck appears in the scope.
• The scope doesn't scroll. It advances while audio flows and holds on silence. Play the track, or arm + monitor it.
• Bypass sounds quieter, not different. That's the point being hidden: enable AUTO so wet and dry are level-matched, then bypass again and judge the compression itself.
• Two lanes behave differently than expected. Check which lane your chips belong to — in L/R and M/S each lane has its own full parameter set. The lane tag (L, R, MID, SIDE) sits at the left of each chip bar.
• Peak GR seems stuck. It's the held maximum — double-click the GR meter to reset it.

DeltaComp — compression you can see. 🖤