Crestwave Multibend is a multiband saturation plugin by UDI DSP.

01 What Crestwave Multibend is

Crestwave Multibend splits your sound into four frequency bands and saturates each one on its own terms. The low end can take a whisper of warmth while the mids get real grit and the top gets a little air — all at once, from one plugin, without the bands smearing into each other.

In every band you choose a TYPE — WARM, GRIT or CLIP — and turn that band’s DRIVE. Each type runs its whole range on that one knob: inaudible at the bottom, unmistakable at the top, and one character growing stronger in between rather than turning into a different sound.

It is built transparent first: it opens clean, holds the loudness steady while you drive it, and shows you how much each band is adding and where colour turns into distortion. That is where it starts, not where it stops — every type goes all the way to obvious, deliberate distortion when a part calls for it, and you always know which side of the line you’re on.

At a glance

• Four bands, side by side — LOW, LOW-MID, HIGH-MID and HIGH, each with its own TYPE, DRIVE, HOT, MIX and Stereo/Mid/Side switch, all visible at once, like channels on a mixer. Or one, two or three: BANDS in the footer.
• Crossovers you drag — straight on the spectrum.
• Two ways to split — Zero Latency (the default) or Linear Phase, in the menu.
• A spectrum coloured by heat — each band’s part of the live spectrum takes the colour of what that band is adding: steel for clean, amber for colour, red past the line.
• Any band’s own scope — click a band, or its expand icon, to see its waveform, its curve and what it adds.
• Solo and mute per band — several at once, saved with your project and automatable.
• Mid/Side per band — keep the low end mono and tight while the top band adds width on the sides.
• AUTO GAIN and CALIBRATE — judge tone, not volume, and get the same result from one DRIVE setting on any track, band by band.
• The ADVANCED page — EVEN/ODD, ENVELOPE, DUCKING (from the track or a sidechain) and PULSE, for every band.
• Oversampled 2× by default — Off, 2×, 4×, 8× and 16× in the menu, set separately for playing and for exporting.
• CPU — about 5.0% of one core at the defaults (four bands, 48 kHz stereo), about 0.6% while no audio plays, and less with fewer BANDS (chapter 09).

Which one do I need?

Crestwave Multibend has a single-band sibling, Crestwave. Reach for Multibend when different parts of the spectrum want different treatment; reach for Crestwave when one character across the whole sound is the job — its FLOOR control already keeps the low end clean, which covers a lot of what people buy a multiband saturator for.

The two are separate products with separate preset libraries. A Crestwave preset doesn’t load in Crestwave Multibend, or the other way round: Multibend’s presets are written to use its four bands.

02 The ideas behind Crestwave Multibend

Three types in every band

Saturation is what happens when a sound is pushed into a curve that bends: its peaks are rounded, and the bending adds harmonics — new tones above each note — that make a sound denser, warmer or more present. How the curve bends decides which harmonics you get, and that is what a type is. Each band has a complete saturation engine of its own, running whichever of the three types you choose, with its own oversampling and output stage; around the four, the split keeps the bands and their dry signals lined up to the sample.

Each type is voiced so that turning DRIVE from the bottom to the top sounds like one character getting stronger, not several sounds glued end to end. Each also carries a few dB of gentle compression as part of its character, working on both channels together so the stereo image stays put.

WARM

Tube-style warmth, rounded and forgiving. Gently, it adds mostly the tone an octave above each note, which blends in as body rather than being heard as an effect; pushed, the odd harmonics catch up and it thickens into a driven stage. For low end, mix buses, and anything that should feel fuller without sounding processed.

GRIT

Transistor-style bite. Its curve reaches its ceiling more slowly, so more of the higher harmonics come through, and it reads as edge and presence rather than warmth. For parts that need to cut through: vocals, guitars, snares, the attack of a bass.

CLIP

A clipper whose corner gets sharper as you drive it: rounded at the bottom of the knob, a hard edge at the top, so clipping arrives gradually rather than switching on at a threshold. For transients and loudness: shaving peaks, an 808's growl, a master pushed hard.

Reading the pictures. The top of each shows one cycle of a sine at DRIVE 30, 60 and 100% (HOT at 100%), each line coloured by what that setting adds, as the panel colours it; the dashed line is the input. The bottom shows which harmonics the type adds, in dB under the note, with all three adding the same amount, 3%, so the bars compare character rather than quantity: WARM leads with the 2nd harmonic, GRIT pairs the 2nd and the 3rd with more above them, and CLIP runs the odd series — 3rd, 5th, 7th — up high.

Transparent first

• With every band at DRIVE 0, nothing is saturated. In Linear Phase the output is exactly your input, delayed. In Zero Latency every frequency comes out at your input’s level, but the split itself shifts the timing very slightly around each crossover (chapter 09).
• A fresh instance opens gently: every band on WARM at DRIVE 12%, HOT off.
• HOT sets how far each band’s DRIVE knob reaches. Off, a full turn covers the gentler part of the type’s range — still enough to reach real distortion in the top half — and at 100% the same turn goes all the way.

Seeing what each band adds

ADDING is how much harmonic content is reaching your track, as a percentage of the signal. The spectrum shows it for the whole track and for each band, and each band’s figure is its share of the whole — so a band with its MIX turned down, or a band that’s muted, adds less or nothing, and the reading says so.

Each type has its own warning line, the amount at which it starts to be heard as distortion rather than colour. The lines were set by ear:

Below the line, a band glows amber; past it, red. Since the bands can be on different types, the whole-track reading is held to the line of whichever band is adding the most.

The same setting in every band, on every track

A saturator reacts to level, and in a multiband the bands of one track can sit tens of dB apart — the top of a dark mix is far quieter than its lows. CALIBRATE works band by band: it brings each band to one fixed working level before the saturation and undoes that afterwards, so it never changes how loud anything is. The result is that a DRIVE setting means the same in every band and on every track.

The picture is measured: a drum loop with every band on WARM at DRIVE 30%. With CALIBRATE off, the quiet upper bands hardly take any drive. With it on, every band is worked at the same level, and what still differs is the material: the snare and hi-hats in the upper bands are peakier than the kick and bass, and peaks are what a curve works on.

The consequence to know about: a quiet band is driven as hard as a loud one at the same DRIVE. On a dark mix, the HIGH band at DRIVE 30% is driven as hard as the LOW band at 30%, even though there’s much less of it. CALIBRATE lifts a quiet band by up to 18 dB, and leaves a band that’s essentially silent alone. Turn CALIBRATE off if you want each band to react to how much level it actually has.

AUTO GAIN takes the level rise of saturation back out in every band, so you compare colour, not volume.

Running on many tracks at once

Crestwave Multibend keeps its CPU use low in four ways, none of which changes its output:

• Silence. When the input goes silent and its output has settled, it stops processing and only keeps count of time, so it continues exactly where it would have been. That costs about 0.6% of one core, at any oversampling setting.
• Mono. When both channels carry the same signal, it processes one and copies the result to the other.
• Meters. ADDING, CORR, the spectrum and the band scopes are computed only while the panel is open.
• Vector instructions. It processes several samples at once: SSE2 on every machine, AVX2 where the processor has it; the Zero Latency split runs both channels together.

Fewer bands, less work

BANDS at 1, 2 or 3 builds no split, or a two- or three-way one; it doesn’t mute bands of a four-way one. Fewer crossover filters process the signal — none with one band — and the CPU drops with them. With the bands in use driven: one band, 1.6% of one core at 2× and 4.8% at 16×; two, 2.7% and 8.2%; four, 4.3% and 17%.

Oversampling and exports

The oversampling filters are linear-phase: every frequency is delayed by the same amount, so the shape of the waveform is kept. The menu has two settings: Playing, what runs while you play and mix, and Exporting, what an offline export runs at — Same as Playing unless you choose another, higher or lower. So you can mix at a light setting and export at a higher one. Crestwave Multibend reports the larger of the two latencies, so the timing doesn’t move when it switches (chapter 07). Oversampled, each band’s ADDING is measured after the same downsampling filters as its output, so it counts only what reaches your track.

03 Signal flow

Each band’s MIX blends the band against itself, delayed to match, so a parallel blend inside a band lines up to the sample.

The master MIX’s dry side is what the split adds up to, not the raw input. That way the dry and the processed signals have been through the same split, and a partial blend can’t comb.

A silenced band leaves on both sides of the master MIX. When a band is soloed away or muted, its dry signal goes with it; otherwise turning the master MIX down would bring it back.

The output stage in each band is a gentle roll-off at the very top whose corner follows that band’s DRIVE, after the band’s MIX.

04 The panel

Across the top

The name on the left. On the right, from the edge inwards: POWER, the menu (☰), the button that shows or hides the visualizer, and the preset field with its < and > steps.

The spectrum

The display across the top is the live spectrum of your track, split into its bands at the crossovers.

• Each band’s part of the spectrum is coloured by what that band is adding — steel where it’s clean, amber for colour, red past its type’s line. So colour always means the same thing on this panel: how much, never which frequency.
• Each band’s name and its ADDING figure sit at the top of its region. A band that’s muted or soloed away reads SILENT and dims.
• The crossovers are the vertical lines, each with its frequency: three with four bands, fewer with fewer, none with one. Drag one to move it.
• Click a band to open its own scope (below). Click another band to switch; click the open band again to go back to all of them. Near a crossover, a press takes the crossover instead.
• ADDING, top left, is the whole track’s reading, marked ALL BANDS. The ADDING gauge at the right draws the same number, and CORR beside it is the mono-safety meter: +1 when the two channels are the same, 0 when they’re unrelated, below 0, in red, when they’d start to cancel in mono. It reads what leaves the plugin, and shows nothing in silence.

The visualizer button in the header (or Show Visualizer in the menu) hides the display. The panel gets shorter; nothing else changes size.

The band strips

One strip per band, LOW on the left to HIGH on the right: four, unless BANDS says fewer. With one band, its strip is FULL, with the band’s scope open beside it. Each reads the same way:

• The title row: the band’s name, then S (solo), M (mute) and the expand icon.
• TYPE down the left, and the band’s DRIVE beside it.
• HOT, the STEREO / MID / SIDE switch and the band’s MIX along the bottom.

A band’s own scope

Click a strip’s expand icon, or click the band in the spectrum. That strip moves to the left, and the space of the other strips shows the band’s own heat scope, fed by this band alone:

• The waveform of the band as the saturation sees it, scrolling in from the right, each moment coloured by what it adds to your track.
• Dashed lines, labelled with the type’s line, at the peak level where this band reaches that line. Peaks past them are being distorted; no lines means this setting never gets there.
• ADDING for this band, with COPY beside it when the band’s MIX or the master MIX is blending less than all of it in, and EVEN and ODD: how the band’s added content splits between the octave-led harmonics that read as fullness and the others, which read as edge.
• CURVE: the shape this band’s setting pushes the signal through, red where a peak that large would be distorted, with the last moments of the signal marked on it.

Click the icon again, or the open band in the spectrum, to go back to all the strips. The scope is only a view: opening one doesn’t change what you hear, and solo does that separately (chapter 06). The panel always opens showing every band’s strip.

OUTPUT

On the right: the master MIX, IN and OUT below it, and the input and output meters. AUTO GAIN and CALIBRATE sit in the card’s title row. The small padlock beside MIX’s value holds the master MIX, IN and OUT when you change presets (chapter 07).

The footer

ADVANCED, at the bottom left, swaps the strips for the ADVANCED page (chapter 08). The spectrum and OUTPUT stay where they are. BANDS, at the bottom right, sets how many bands the split makes: 1, 2, 3 or 4 (chapter 05).

Panel size and tooltips

Panel Size in the menu picks 75, 100, 125 or 150%, and that becomes the size every new Crestwave Multibend opens at on this computer. Dragging the bottom-right corner resizes only the instance you’re in, and your project remembers it. Show Tooltips turns the help text on every control on or off; it starts on.

05 The bands

Every control here can be automated and is saved with your project. Double-click a knob to return it to its default. Every band has the same controls; only its frequency range differs.

TYPE

WARM · GRIT · CLIP · default WARM

The band’s character. Switching while audio plays passes that band through its clean signal for about 20 ms, so the change can’t click. In your host’s automation list, each band’s TYPE has a fourth position, Reserved, which plays with no saturation.

DRIVE

0 – 100% · default 12%

How much of the band’s type. At 0 the band isn’t being saturated at all.

HOT

Off – 100% · default Off

How far this band’s DRIVE knob reaches. Off, a full turn covers the gentler part of the type’s range; at 100% it goes all the way. HOT stretches the whole knob: DRIVE 0 is always clean, and every other position reaches a little further as HOT goes up. Each band has its own.

STEREO / MID / SIDE

default STEREO

Which part of this band’s stereo image is saturated, with the band’s TYPE and DRIVE:

• STEREO — both channels, as they are.
• MID — only what the channels share. On the LOW band this keeps the bottom mono and tight.
• SIDE — only what differs between them. On the HIGH band this adds air and width without touching the centre.

The part that isn’t saturated passes through from the band’s own clean signal, untouched. A change passes through the clean signal for about 20 ms, so it doesn’t click. On a mono track the switch has nothing to split, and the band is saturated as it is.

MIX

0 – 100% · default 100%

The band’s own dry/wet, blended against the band itself and lined up to the sample. Driving a band hard and blending a little of it in is parallel saturation for just that part of the spectrum.

The crossovers

Drag the lines on the spectrum. Each has its own range, and they overlap, so any split can be made:

Crestwave Multibend keeps neighbouring crossovers at least a major third apart, so no band can be squeezed to nothing. The crossovers are automatable and saved with presets. With fewer bands, only the crossovers the split uses are on the spectrum (below).

BANDS

1 · 2 · 3 · 4 · default 4

In the footer, at the bottom right. How many bands the split makes:

• 1 — FULL: no split, the whole signal through one band, with LOW’s settings. Its S and M are hidden: there’s nothing to choose between.
• 2 — LOW and HIGH, split at the middle crossover.
• 3 — LOW, MID and HIGH, split at the low and high crossovers.
• 4 — LOW, LOW-MID, HIGH-MID and HIGH, at all three.

The strips follow: the bands in use share the width between them, and the spectrum shows only their regions and the crossovers they use. With one band, FULL’s strip takes the first place and its scope the rest, as when you open a band.

A band you aren’t using keeps its settings for when you bring it back; with three bands, MID is the LOW-MID strip’s settings. Fewer bands is a smaller split, not four with some hidden: with one, there’s no split at all; with two, a single crossover shapes the sound; and fewer bands take less CPU.

Changing BANDS passes through your clean signal for a moment, so it doesn’t click. It’s saved with your project and carried by presets, but it isn’t automated. The factory presets are all written for four bands, so loading one puts BANDS back to 4. The latency is the same at every setting.

06 Solo and mute

Each strip’s S and M buttons choose which bands you hear. With one band there’s nothing to choose between, and they’re hidden.

• Click to switch one on or off.
• Ctrl-click to solo or mute that band alone, switching the others off.
• Hold the button to solo or mute the band only while the mouse is down; let go and it returns to how it was.

Several bands can be soloed at once, as on a mixing desk, and with every band soloed you hear them all. Mute wins over solo: a band that’s both soloed and muted is silent. Every change fades over 10 ms, so it never clicks — from a click or from automation.

Solo and mute are real controls: saved with your project and automatable, so muting a band for a bar or two is one automation lane. They are never stored in a preset, and loading a preset doesn’t change them — a preset that silently muted three bands would just sound broken.

The meters follow what you hear. A silenced band adds nothing to ADDING and reads SILENT on the spectrum.

07 Global controls

MIX

0 – 100% · default 100%

The master dry/wet, for every band together, blended against what the split itself adds up to so a partial blend can’t comb.

IN and OUT

−24 to +24 dB · default 0 dB

Level trims. IN is before everything; OUT is after everything.

The padlock

Locked / Unlocked · default Unlocked

The small padlock beside the master MIX’s value. Locked, loading a preset leaves the master MIX, IN and OUT where you have them, so you can step through presets at your own blend and level and hear each one in your track. Everything else in the preset loads as usual, each band’s own MIX included. It holds whichever way the preset arrives: the preset menu, the < and > steps, or your host’s own preset list.

A preset you save still stores MIX, IN and OUT, and while the padlock is closed, moving them doesn’t put the modified dot beside the preset’s name. The lock belongs to this instance of Crestwave Multibend and is saved with your project, never in a preset. It isn’t a parameter, so your host can’t automate it.

AUTO GAIN

On / Off · default On

Keeps each band’s loudness steady as its DRIVE moves, so you judge tone, not volume. Turn it off when the level rise is part of what you want.

CALIBRATE

On / Off · default On

Makes one DRIVE setting mean the same on a quiet track and a loud one, band by band (chapter 02). It settles on new material over a couple of seconds, and it holds through pauses: while the track is silent or has dropped more than 20 dB, it stops listening, so a phrase after a gap comes back at the drive it left with. With CALIBRATE on, IN changes loudness rather than colour; with it off, IN is how hard you hit every band.

POWER

Bypasses Crestwave Multibend with a 20 ms crossfade. Bypassed, your signal comes out untouched and still delayed by the same latency, so switching POWER never moves the track in time. The panel dims below the header while it’s off. Your host’s own bypass does the same.

08 The ADVANCED page

Open it with ADVANCED in the footer. Three cards, each shared by every band: EVEN/ODD & ENVELOPE, DUCKING and PULSE. They start off or centred, so opening the page changes nothing until you turn something.

EVEN/ODD

Even 100% – Centre – Odd 100% · default Centre

Fine-tunes every band’s character. Toward EVEN, fuller: more of the tones an octave above the note, which blend in as body — in every type, CLIP included. Toward ODD, those tones fade out and each type’s bare edge is left, which mostly sounds a little cleaner. At Centre, each band’s type is exactly as it was voiced.

It’s deliberately subtle: it changes how full the saturation sounds more than how dirty. Each band’s TYPE is still the main choice of character; this is one knob for all of them.

ENVELOPE

Off – 100% · default Off

Hits bloom and push. For a moment on each hit, the saturation gets a little warmer and drives a little harder, then settles back, so attacks come out thicker and slightly crunchier without coming out louder. Held notes are left alone. Each band listens to its own part of the spectrum, so a band reacts when something hits in its range. At 100% a strong hit drives up to 1.6 times the band’s DRIVE, never past what its HOT allows; a band at DRIVE 0 stays clean.

DUCKING and SOURCE

DUCKING Off – 100% · default Off · SOURCE SELF / SIDECHAIN · default SELF

Takes every band’s DRIVE back while a hit plays and returns it afterwards: the attack comes through clean and the body behind it is saturated.

• SELF ducks on this track’s own hits, with no routing.
• SIDECHAIN ducks on whatever your host sends to the plugin’s sidechain input — a kick ducking the saturation on a bass, for example. How you route a sidechain depends on your host. With nothing routed, SIDECHAIN ducks nothing.

It listens for hits, sudden rises above the source’s own recent level, so a loud steady sound like a pad doesn’t duck. It reacts at once and lets go over about 150 ms.

PULSE, RATE and SHAPE

PULSE Off – 100% · default Off · RATE 1/32 – 8 Bars, or 0.05 – 20 Hz · default 1/4 · SHAPE SINE / TRIANGLE · default SINE

Every band’s DRIVE rises and falls in time with your song. Each band’s DRIVE knob is the top of the cycle, and PULSE is how far below it the bottom goes — at 100% the bottom is clean. So PULSE only ever takes drive away.

• RATE: with the note button lit, a note value from 1/32 to 8 Bars, locked to your song’s position (a bar follows your song’s time signature: in 3/4, 1 Bar is three beats); with it off, a free rate from 0.05 to 20 Hz.
• SHAPE: SINE for a smooth swell, TRIANGLE for a straight rise and fall.

With the transport stopped, a synced PULSE keeps running at the right speed on its own, and after a loop or a jump it eases back into step.

09 Crossovers, oversampling and latency

Both of these are in the menu (☰), not on the panel, because both change the plugin’s latency. Both are saved with your project; neither is automated or stored in presets.

Crossovers: Zero Latency or Linear Phase

Zero Latency (the default) splits the bands without adding any delay of its own. Put back together, the bands come out at your input’s level at every frequency, flat, but with a very small shift in timing around each crossover — the price every zero-latency split pays. On almost everything you won’t hear it, and nothing in Crestwave Multibend combs against it, because the master MIX’s dry side goes through the same split.

Linear Phase splits the bands with no timing shift at all: with every band at rest, the output is exactly your input, delayed. The cost is about 27 ms of extra latency, and on very low crossovers a faint pre-echo is possible just before sharp hits like a kick. It’s the choice for mastering, where a band’s timing has to stay exactly where it was.

In either mode, dragging a crossover while audio plays is smooth; in Linear Phase the move crossfades over 20 ms.

Oversampling

Saturation makes new, higher tones, and pushed hard, some can land above what the session can hold and fold back down as harsh “digital fizz”. Running each band’s saturation at a higher internal rate keeps that out.

Oversampling in the menu holds two settings, Playing and Exporting (below), each Off, 2× (the default), 4×, 8× or 16×. Both are saved with your project. A new Crestwave Multibend always opens at 2×, exporting the same, whatever you chose elsewhere. With four bands each running its own saturation, 2× is where Multibend starts: by our measurements it keeps the fizz out even at the hardest settings, at about 60% of the CPU of 4×.

The picture is the hardest case, measured: a 7 kHz tone through CLIP at full DRIVE and HOT in every band, whose harmonics run far above the audible range. Every red line is an alias — a harmonic folded back to a frequency unrelated to the note. The worst alias at each setting, in dB under the tone:

For mastering, or CLIP driven hard on bright material, 4× and up take it out of reach.

Playing and Exporting

Playing is the setting that runs while your host plays in real time: what you hear, and what your CPU pays for, while you mix. Exporting is the setting an offline export runs at: Same as Playing (the default), or any of the five. Play at 2× and export at 16× to mix light and render at the highest quality, or set Exporting lower for a quicker export. Each submenu’s name shows its current setting, and both are saved with your project.

It switches when your host says it’s rendering offline, which is what an offline export or bounce does in most hosts. A bounce your host plays in real time, or one from a host that doesn’t say, runs at the Playing setting. If you’re not sure what yours does, set Exporting to Same as Playing before your final export.

The latency doesn’t move when it switches: Crestwave Multibend tells your host the larger of the two settings’ latencies and holds the other back to match, so the export lines up exactly with what you heard. So with Playing at Off and Exporting at another setting, the plugin still reports that setting’s latency while you play; for zero latency, set Exporting to Same as Playing (or Off) too.

Latency

The total is the split’s latency plus the oversampling’s:

So “Zero Latency” is the split’s own delay. With oversampling on, the oversampling still adds its few samples; with oversampling Off as well, the whole plugin runs at zero latency.

Crestwave Multibend tells your host its latency, and the host delays everything else to match. Only these menu settings change it; DRIVE, TYPE, the crossovers and everything else you can automate leave it where it is. With Exporting set apart from Playing, the oversampling’s part is the larger of the two settings’ figures above.

10 Presets

The preset field is in the header. < and > step through every preset, factory then yours, and wrap round. Click the field for the full menu:

• Factory — 30 presets and Default, in six groups of five: Mix Bus & Master, Drums, Bass, Vocals, Guitars & Keys and Creative. Each one uses the bands — a clean sub under a driven body, a crunchy snare band over an untouched kick, air on the top band’s sides. Some stay colour; others go past the line on purpose.
• User — your own. Save overwrites the user preset you have loaded (on a factory preset it asks for a name instead); Save As… saves a new one; Delete removes the loaded user preset, and asks first. Put a forward slash in a name to file it in a folder — Drums/Kit Split. Open Preset Folder shows where they are kept.

A dot beside the preset’s name means you’ve changed something since loading it. Default returns every control to its factory value.

A preset is a whole setting: loading one resets every control first, then applies the preset. It carries every band’s settings, the crossovers, BANDS, the master MIX, AUTO GAIN, CALIBRATE and the ADVANCED page. It never carries POWER, your host’s bypass, or solo and mute. The menu settings — the crossover mode, and oversampling’s Playing and Exporting — aren’t part of a preset either.

To audition presets at your own blend and level, close the padlock beside the master MIX first (chapter 07): the master MIX, IN and OUT then stay where you set them, and every other control still loads.

A preset change that moves a control a long way passes through the clean signal for about 20 ms, so stepping between very different presets doesn’t click.

Your presets live in %APPDATA%\udidsp\Crestwave Multibend. Uninstalling leaves them where they are.

11 Technical specifications

Activation. Click the badge in the header, or Activate… in the menu. The trial, the demo and activation work the same way in every UDI DSP plugin, so they’re explained once, on the support page.

About. About Crestwave Multibend… in the menu shows the version and build. Include them in any bug report — they pin down exactly which Crestwave Multibend you’re running.