Carbonated Audio FOAM Ducks Reverb Into the Gaps
Carbonated Audio FOAM is a $49 ducking reverb that pulls its own tail down while the dry signal plays, then lets it bloom in the gaps. Specs, comparison, FAQ.
Carbonated Audio has released FOAM, a reverb built around one old mixing trick made automatic. While the dry signal plays, FOAM pulls its own reverb down. In the gaps between words, hits, or phrases, the tail returns. The reverb never fully stops, so the space stays alive underneath the part instead of being gated off. The license is $49, one time, sold direct. This is a first look based on Carbonated Audio's official product page, not a hands-on review.
At a glance: FOAM is a ducking reverb. Its Make Room control lowers the tail by up to 36 dB while the source is present, with recovery set in note values or milliseconds. A Detector listens to FOAM's own input by default, or to an external source. One Size and Bloom field shapes the room across ten factory spaces, and a four-point Tail Shaper draws the tail against the dry signal on a tempo grid. Decay, Pre-Delay, and Recovery all sync to tempo or run free. It loads as a send (reverb only) or an insert (equal-power wet/dry), reports zero latency with no lookahead, and runs under 1% of one core on an Apple M4 at 48 kHz. Formats are VST3, AU, and AAX on macOS 11 and later, and VST3 on Windows 10 and 11. The price is $49, one time, up to three machines, no dongle or account. Buy it from Carbonated Audio.
What FOAM is
Ducking a reverb isn't new. Engineers have sidechained a reverb return to the lead vocal for decades, so the dry voice stays clear and the tail swells only in the spaces. The usual way to do it is a compressor on the reverb bus, keyed from the dry track, with a send, a bus, a sidechain cable, and three plugins to balance. FOAM folds all of that into one insert and makes the ducking the center of the design rather than an afterthought.
That focus is the whole pitch. FOAM isn't trying to be the deepest algorithmic reverb or the most accurate convolution. It's a reverb you reach for when a part is busy, and a normal reverb would turn it to mud. It keeps the dry signal in front, then fills the silences. On a lead vocal, a rap, a busy synth arp, or a snare in a dense mix, that behavior is the difference between a sound that breathes and a sound that washes out.
Carbonated Audio is a small developer with a habit of building single-purpose tools. Its ducker, On Tap, does the same job for any effect, with hand-drawn ducking curves and a band-split crossover, at a lower price. FOAM takes that ducking idea and bakes it into a reverb, so there's nothing to route. If you already know the TALLBOY console-chip resynth plugin, this is the same studio's approach applied to space instead of pitch. The TALLBOY first look covers that one.
How the ducking works
The ducking lives under a control the plugin calls Make Room. It lowers the wet signal by up to 36 dB while the detector hears energy at the input, then brings the tail back as the input falls away. That 36 dB of range matters. A small dip gives gentle polish. Wind it up and the tail all but disappears for a hard pumping effect, all from one knob.
Recovery sets how fast the tail returns once the source stops. Set it in note values and the bloom locks to the tempo, so the reverb swells in time with the track. Choose milliseconds and the response stays fixed whatever the BPM. Note-based recovery is what makes a ducked reverb feel musical instead of mechanical: the tail returns on the beat, not whenever the gate happens to open.
The Detector decides what triggers the ducking. By default it listens to FOAM's own input, which is the simple case: the louder the signal going into the reverb, the harder the tail ducks. Switch it to an external source and you can key the ducking from a different track. A vocal reverb can duck to the kick, or a pad's tail can pump against the lead. That external detector turns FOAM from a one-trick vocal reverb into a creative rhythmic effect.
Shaping the space and the tail
The room itself is set from a single Size and Bloom field, an XY pad with ten factory spaces behind it. Instead of a page of decay, diffusion, and damping sliders, you move one point to set character and length. The ten spaces give you starting points, from tight rooms to long blooms. It's the fast, opinionated end of reverb design, in the same spirit as the plugin's single ducking knob.
Over the top sits the Tail Shaper, and this is the part that rewards a closer look. It gives you four points, Onset, Build, Body, and Decay, that shape the level of the tail across its life, drawn against the dry signal on a tempo grid. So the reverb doesn't just decay at one rate. You can hold the body of the tail, fade the onset in, or carve the decay so it drops away on a musical division. With the ducking on top, FOAM shapes the tail on two axes at once: the Tail Shaper draws the overall envelope, and Make Room pulls it down whenever the dry part needs space.
Tempo sync runs deep. Decay, Pre-Delay, and Recovery can all follow the project tempo or run free. If the host sends no tempo, FOAM falls back to a manual BPM, so sync still works in a live rig or a standalone setup. Width and Tone controls finish the signal, widening the tail's stereo image and tilting its brightness so the reverb sits where you want it.
The last structural choice is how you load it. In Send mode, FOAM outputs reverb only, the right behavior on an effects bus fed by aux sends. In Insert mode, it gives an equal-power dry and wet mix on a single channel, which is how most producers now work inside a DAW. It reports zero latency and uses no lookahead, so it won't drag timing while you track, and the sub-1% CPU figure the developer quotes on an Apple M4 lets you run several instances without a hit.
FOAM specifications
| Spec | Detail |
|---|---|
| Type | Ducking reverb |
| Developer | Carbonated Audio |
| Ducking | Make Room, up to 36 dB, recovery in note values or milliseconds |
| Detector | Internal by default, switchable to an external source |
| Room | Size and Bloom XY field, ten factory spaces |
| Tail Shaper | Four points (Onset, Build, Body, Decay) on a tempo grid |
| Tempo sync | Decay, Pre-Delay, and Recovery, with manual BPM fallback |
| Routing | Send (reverb only) or Insert (equal-power dry/wet) |
| Tone and width | Tilt-style Tone control plus stereo Width |
| Latency | Zero samples, no lookahead |
| CPU | Under 1% of one core on an Apple M4 at 48 kHz, per the developer |
| macOS | 11 or later, universal (Apple Silicon and Intel), VST3, AU, AAX (Pro Tools signed) |
| Windows | 10 and 11, 64-bit, VST3 only (no AAX) |
| License | $49 one time, up to three machines, no dongle or account |
| Demo | Full plugin, plays 60 seconds then mutes 10, on a loop, no email |
FOAM vs Crystalline vs Valhalla VintageVerb
Ducking shows up in plenty of modern reverbs now, so why buy one that only ducks? It comes down to how deep FOAM goes on that single feature, and the price. Baby Audio Crystalline is a full algorithmic reverb with a Ducker and a Ducker Gentle mode among its freeze, reverse, shimmer, and gated effects, and it's the closest feature rival. Valhalla VintageVerb is the mix workhorse with no ducking at all, the one you'd pair with an external sidechain if you went the classic route.
| Carbonated Audio FOAM | Baby Audio Crystalline | Valhalla VintageVerb | |
|---|---|---|---|
| Price | $49 one time | $99 regular | $50 |
| Ducking | The core of the plugin, up to 36 dB, internal or external key | Built-in Ducker and Ducker Gentle modes | None, use an external sidechain |
| Tail control | Four-point Tail Shaper on a tempo grid | 300-plus presets, macro controls | Classic room, hall, plate, and chamber modes |
| Room design | One Size and Bloom field, ten spaces | One-screen macro workflow | Mode plus decay, size, and color EQ |
| Formats | VST3, AU, AAX (Mac), VST3 (Win) | VST, VST3, AU, AAX | VST, VST3, AU, AAX |
| Best when | The dry part must stay clear and the tail fills the gaps | You want one modern reverb that also ducks | You want the standard algorithmic reverb sound |
Choose FOAM when ducking is the point and you want it deep, musical, and keyed to tempo without building a sidechain. Crystalline makes more sense if you want one modern reverb that covers shimmer, gating, and ducking in a single window, and you don't mind paying twice as much. Reach for VintageVerb when you want the classic algorithmic sound that drops into a mix instantly, and you're happy to add ducking yourself when a part needs it. For the wider paid field, our best reverb plugins of 2026 guide ranks the category.
Who FOAM is for
FOAM suits producers and mixers who work with busy, upfront parts: rap and pop vocals, dense electronic arrangements, and drums that need space without smear. If you've ever put a reverb on a lead and then pulled it back out because it buried the words, FOAM is built for that moment. The external detector also makes it a creative tool. A sound designer can pump a pad's tail against a kick and get a rhythmic, breathing ambience from one insert.
Skip it if you need a surgical reverb with frequency-dependent decay, convolution of real rooms, or detailed early-reflection editing. FOAM trades that depth for one strong idea. It's also the wrong call if your only reverb need is a static plate behind a ballad, where a classic algorithmic reverb does the job without the ducking machinery. And if you're on Windows with Pro Tools, note that FOAM ships no AAX for Windows yet, so Pro Tools on a PC is out for now.
How much does FOAM cost?
FOAM is $49, a one-time purchase with no subscription. The license covers up to three machines, with no dongle and no account: you activate once online, then it runs offline. Moving an activation is a matter of emailing the vendor for a reset. Carbonated Audio states that all sales are final, with broken, undelivered, or double-charged orders handled by email.
The demo is the full plugin, free, with no email required. It plays for 60 seconds, then mutes for 10, on a loop, which is enough to audition it across a real session before you commit. Buying swaps the demo for the full installer, and your sessions keep their settings. Formats are VST3, AU, and AAX on macOS 11 or later (universal, with the AAX signed for Pro Tools), and VST3 on Windows 10 and 11. Download the demo or buy from Carbonated Audio.
FAQ
How much is Carbonated Audio FOAM?
FOAM is $49, a one-time purchase sold direct by Carbonated Audio. The license covers up to three machines with no dongle and no account, and there's a free, full-feature demo that plays for 60 seconds then mutes for 10 on a loop.
How is FOAM different from a normal reverb with a sidechain?
FOAM builds the ducking in, so there's no send, bus, or compressor to set up. Its Make Room control lowers the tail by up to 36 dB while the source plays, with recovery in note values or milliseconds. The detector can listen internally or to an external track. A standard reverb needs a separate sidechained compressor on its return to do the same job.
FOAM vs Baby Audio Crystalline?
Crystalline is a full modern reverb at $99 that includes a Ducker mode among many effects. FOAM is a dedicated ducking reverb at $49 that puts the ducking, a four-point Tail Shaper, and tempo sync at the center. Pick Crystalline for one do-everything reverb, and FOAM when ducking is the whole reason you're adding the plugin.
What formats and systems does FOAM support?
VST3, AU, and AAX on macOS 11 or later, as a universal build for Apple Silicon and Intel, with the AAX signed for Pro Tools. On Windows 10 and 11 it's VST3 only, so there's no AAX and no Pro Tools support on a PC yet.
Does FOAM add latency?
No. FOAM reports zero samples of latency and uses no lookahead. The developer quotes CPU under 1% of one core on an Apple M4 at 48 kHz, so it's usable while tracking and light enough to run on several channels.
FOAM is a single strong idea built well: a reverb that gets out of the way of the dry part and blooms in the gaps, with the ducking keyed to tempo and shaped on a grid. At $49 it undercuts the do-everything reverbs while going deeper on the one feature a busy mix actually needs. The spec sheet lives on the FOAM plugin card, and for another small, specific Carbonated Audio tool, the TALLBOY first look is the companion read.
