Free De-Reverberation Plugin
with Automatic Room Analysis
Orra Deverb is a free de-reverberation plugin from Orra Audio designed to reduce unwanted room sound, ambience and reverb tails from existing recordings.
Unlike conventional noise-reduction tools, Deverb specifically targets the decay of a room after notes, words or transients. It works on a single mono or stereo track without requiring a separate reference signal, making it suitable for vocals, dialogue, instruments, drums and even complete mixes recorded in less-than-ideal acoustic spaces.
Its standout feature is Scout, an automatic analysis system that listens to the recording, estimates the characteristics of the room and configures the most important parameters automatically.
Orra Deverb is available on a free / pay-what-you-can basis for Windows and macOS.
Remove Room Sound from Existing Recordings
Unwanted ambience can be difficult to fix after recording.
A microphone placed too far from a singer, an untreated bedroom, a rehearsal space or a reflective studio can leave audible room decay behind every phrase.
Orra Deverb is designed specifically for this situation.
The plugin attempts to separate:
- The direct source
- The reverberant room tail
and then attenuates the room component while keeping the original signal as intact as possible.
The important distinction is that Deverb does not attempt to reconstruct a completely new signal.
Instead, it changes the level of individual frequency regions over time while preserving the original phase.
No Reference Signal Required
Many restoration processes rely on a separate noise profile or reference recording.
Orra Deverb does not.
It works directly from the recording itself.
The plugin analyzes how energy behaves after musical notes, drum hits or spoken phrases and uses those decays to estimate the acoustic characteristics of the room.
This makes it practical for recordings where nothing except the final audio track is available.
Scout Automatically Measures the Room
The most distinctive feature is Scout.
Press Scout and play a passage containing pauses or clearly audible note endings.
Deverb listens to the tails following those sounds and estimates the room automatically.
Analysis normally takes between:
8 and 30 seconds of audible material
Scout stops automatically once it has gathered enough useful information.
If fewer than four usable reverb tails are detected, it does not guess.
Instead, it reports how many usable tails were found and leaves the parameters unchanged.
That is a sensible approach because continuous or heavily sustained material may not provide enough isolated decay information for reliable measurement.
What Scout Automatically Sets
Scout adjusts several important parameters.
Room Decay
This represents the room’s approximate RT60 — the time required for the reverberant energy to decay by 60 dB.
The supported range is:
0.15 to 3.00 seconds
Scout attempts to measure this from the diffuse part of the signal so that the natural fade of the instrument itself is less likely to be mistaken for room decay.
Reverb Level
This determines how loud the reverberant component is relative to the direct sound.
Range:
−24 to 0 dB
On stereo material, Scout estimates this partly from left-right coherence.
Max Reduction
Scout chooses a maximum attenuation intended to push the detected room tail roughly 40 dB below the source, subject to the plugin’s available reduction range.
Preserve
Scout adjusts protection according to the type of material.
Sustained or tonal sources receive more protection.
Percussive material can tolerate more aggressive removal.
Focus
Focus is adjusted toward the frequency area where the room appears stronger relative to the original source.
Reduction
Scout sets the main Reduction control to:
95%
This intentionally leaves one major decision to the user.
After Scout has measured the room, you simply reduce the amount until the result sounds natural.
Parameters Scout Does Not Change
Scout leaves these untouched:
- Smoothing
- Output
Every value written by Scout behaves like a normal plugin parameter change.
That means your DAW can:
- Record it
- Automate it
- Override it
- Undo it
Reduction
The main Reduction knob controls how strongly Deverb applies the separation.
Range:
0 to 100%
At 0%, the output is essentially the original signal, still delayed by the plugin’s internal latency.
Scout initially sets Reduction to 95%, but Orra Audio notes that many recordings work well somewhere around:
60 to 95%
This makes Reduction the main control to adjust after automatic analysis.
Room Decay
Room Decay determines how long Deverb expects the room tail to last.
Range:
0.15 to 3.00 seconds
If the value is too short, long reverb tails may remain.
If it is too long, the processor may begin removing some of the natural decay of sustained instruments.
You can set the value manually or let Scout determine it.
Reverb Level
The Reverb Level control tells the room model how strong the reverb is relative to the source.
Range:
−24 to 0 dB
Lower values provide more protection for sustained sounds.
Higher settings are more appropriate for recordings with very strong room ambience.
This parameter works together with Room Decay to form the core acoustic model.
Preserve
Preserve protects attacks, tonal content and sustained harmonics from being incorrectly classified as room sound.
Range:
0 to 100%
Higher values are recommended for:
- Singing
- Sustained instruments
- Full mixes
- Tonal material
Lower values can provide stronger cleanup for:
- Speech
- Percussion
- Short transients
This is one of the most important controls for balancing transparency against aggressive de-reverberation.
Focus
Focus changes which part of the spectrum receives more reduction.
Range:
−100 to +100%
Move it toward the low frequencies when the room is particularly boomy.
Move it toward the high frequencies when the ambience is brighter than the direct signal.
At the center position, the spectrum is treated more evenly.
Smoothing
Smoothing controls how quickly reduction is allowed to deepen between analysis frames.
Range:
0 to 100%
Higher values produce calmer and more stable processing on sustained sounds.
Lower settings react more quickly to changing material.
This can help prevent the reduction from sounding too nervous or artificial.
Max Reduction
Max Reduction defines the deepest attenuation Deverb can apply at any individual frequency.
Range:
3 to 30 dB
Lower settings preserve more of the natural ambience.
Higher settings can create a much drier result.
Scout may set this automatically up to approximately 28.5 dB depending on its analysis.
Output
The Output control provides final gain adjustment.
Range:
−18 to +18 dB
It affects both the restored signal and the Removed monitoring signal.
Removed — Hear Exactly What Is Being Taken Away
One of Deverb’s most useful features is Removed.
Activate it and you hear only the material the plugin is subtracting.
Ideally, this should contain mostly:
- Reverb tails
- Room ambience
- Diffuse reflections
If you begin hearing too much of the original voice, instrument or transient structure, the processing is probably too aggressive.
This is one of the quickest ways to fine-tune the plugin.
Bypass with Matched Latency
Deverb’s Bypass control passes the original signal while maintaining the same internal delay as the processed signal.
This means A/B comparisons remain time-aligned.
The room analysis also continues while the plugin is bypassed, preventing the internal model from having to start again when processing is re-enabled.
How Deverb Actually Works
Orra Deverb uses a combination of:
- Room-decay modelling
- Short-term prediction
- Frequency-dependent analysis
- Stereo coherence analysis
The audio is examined in overlapping frames of approximately:
43 milliseconds
For each frequency area, the processor asks several questions.
Is the level falling at the rate expected from the room model?
Can the current signal be predicted from the recent past, as reverb often can?
On stereo material, do the left and right channels behave similarly or differently?
A centered direct source tends to remain relatively correlated between channels.
Stereo room ambience often behaves differently.
That additional information helps Deverb distinguish between direct sound and reverberation.
Stereo Image Is Preserved
On stereo tracks, the same attenuation decision is applied to both channels.
This means Deverb does not independently manipulate the left and right sides in a way that could destabilize the stereo image.
The original stereo positioning is therefore preserved as much as possible.
Original Phase Is Preserved
The plugin does not alter the phase of the direct signal.
Instead, it changes gain across frequency and time.
That is an important design decision because aggressive phase manipulation can introduce its own artifacts.
Three Visual Displays
Orra Deverb includes three visualization modes.
Spectrum
Displays the input and restored signals across the frequency spectrum.
Where the restored trace sits below the original, room energy is being reduced.
Reduction
Shows how much attenuation is currently being applied across frequency.
This is useful for seeing which parts of the spectrum Deverb identifies as reverberant.
Tail
Displays the recent level history of both the input and processed signal.
You can literally watch the reverb tail become shorter.
A reference line also indicates the decay expected from the current Room Decay setting.
This makes the Tail display useful both visually and diagnostically.
Six Starting Points
Deverb includes six factory starting configurations:
- Natural / Starting Point
- Vocal / Close & Clear
- Dialogue / Room Control
- Instrument / Keep the Body
- Drums / Tighten the Room
- Mix / Gentle Restoration
These are not room measurements.
They are simply sensible parameter starting points for different source types.
Scout remains the tool intended to measure the actual recording.
A/B Comparison
A built-in A/B system allows two parameter configurations to be compared rapidly.
You can:
- Create one setting
- Copy it to the second slot
- Modify the alternative
- Flip between both
This is particularly useful with restoration tools, where slightly less processing can often sound more natural than a technically drier result.
Tooltips in Seven Languages
Orra Deverb includes multilingual tooltips in seven languages.
The tooltip language is remembered with the session.
The interface itself can also be scaled to:
- 75%
- 100%
- 125%
- 150%
Important Limitation: Early Reflections Remain
Orra Audio is unusually clear about what Deverb does not remove.
The first approximately:
40 milliseconds
after a sound are intentionally left alone.
This region contains early reflections.
Preserving it helps keep the direct sound intact, but it also means the coloration of a very small or boxy room may remain even after the longer tail has been reduced.
That is an important distinction.
Deverb is primarily a late-reverberation reduction tool, not a complete acoustic reconstruction system.
Dense Sustained Material Is More Difficult
Reverberation underneath dense, continuously sustained material cannot always be separated reliably from the source.
Examples include:
- Pads
- Sustained strings
- Dense distorted guitars
- Full mixes with few pauses
There may simply be too little acoustic information to determine what belongs to the instrument and what belongs to the room.
Orra Audio explicitly acknowledges this limitation.
Strong Settings Can Shorten Natural Releases
At aggressive settings, Deverb may shorten the natural release of an instrument together with the room tail.
For example, a piano or cymbal decay could potentially be interpreted partly as reverberation.
This is why Preserve, Max Reduction and the Removed monitoring mode are important.
It Is Not a Noise Reducer
Orra Deverb is not intended to remove:
- Constant hiss
- Air-conditioning noise
- Electrical hum
- Broadband background noise
Steady background noise is neither specifically removed nor added.
For those problems, a dedicated denoising tool is more appropriate.
Delays and Echoes Are Not Reverb
Repeated echoes generated by delay feedback may look somewhat like a decaying room to Scout.
However, they are structurally different from diffuse reverberation.
Scout may measure them as a decay, but the separation stage will not necessarily remove them cleanly.
2048 Samples of Latency
Deverb requires significant analysis time.
Its fixed latency is:
2048 samples
The plugin reports this to the DAW for automatic delay compensation.
Approximate latency is:
- 46.4 ms at 44.1 kHz
- 42.7 ms at 48 kHz
- 46.4 ms at 88.2 kHz
- 42.7 ms at 96 kHz
- 42.7 ms at 192 kHz
This means Deverb is primarily suited to:
- Mixing
- Editing
- Post-production
- Restoration
rather than latency-sensitive live monitoring.
Sample Rate Support
Orra Deverb supports sample rates from:
44.1 to 192 kHz
Its analysis window adapts according to sample rate so the behavior remains consistent.
Mono and Stereo Support
The plugin can process:
- Mono tracks
- Stereo tracks
Stereo processing has access to additional left-right coherence information that Scout can use when estimating the room.
macOS Compatibility
On macOS, Orra Deverb supports:
- macOS 10.13 or later
- Apple Silicon
- Intel
- Universal binary
Plugin formats:
- VST3
- Audio Unit
- AAX
Windows Compatibility
On Windows:
- Windows 10 or later
- 64-bit
Plugin formats:
- VST3
- AAX
Licensing
Orra Deverb is offered as:
Free / Pay What You Can
You can obtain a license for zero cost if desired.
There is no reduced free edition, watermark or permanent feature limitation.
The checkout process provides a normal licence key even when the selected price is zero.
14-Day Full Demo
Before activation, the plugin can run as a full 14-day demo.
The demo can be started once per machine.
Until either the demo or licence is activated, the plugin remains silent.
Online Activation Only Once
Activating the licence requires a one-time connection to Orra Audio’s licensing server.
After activation, the licence is stored locally.
The plugin does not need a permanent internet connection for normal use.
Licences can also be deactivated to free an activation for another machine.
Offline Rendering
The licence gate is not applied during offline bouncing or freezing.
A session that loaded normally can therefore render normally even if licensing changes while that session remains open.
Best Uses
Vocal Recordings
Reduce obvious bedroom, rehearsal-room or untreated-studio ambience around a vocal.
Dialogue
Clean up spoken-word recordings, podcasts, interviews or location audio.
Acoustic Instruments
Reduce excessive room tails from guitars, piano, strings or other microphone recordings.
Drums
Shorten room decay when a drum recording feels too loose or distant.
Full Mixes
Apply gentle de-reverberation to archival recordings or stereo material where the original multitracks are unavailable.
Sample Restoration
Dry up samples before placing them into a completely different production environment.
Re-Reverberation Workflows
Remove part of an unwanted original room and then apply a new reverb that better matches the mix.
A Particularly Useful Workflow
One of the most obvious uses is:
Deverb → EQ / Processing → New Reverb
For example, an old vocal recording might contain too much untreated-room ambience.
Use Deverb to reduce that original environment.
Then EQ and compress the cleaner vocal before placing it into a new artificial room or plate reverb.
This can give considerably more control than simply adding another reverb on top of the existing one.
Strengths
- Free / pay what you can
- Dedicated de-reverberation processing
- Works from a single track
- No reference signal required
- Mono and stereo
- Scout automatic room analysis
- Automatic Room Decay estimation
- Automatic Reverb Level estimation on stereo material
- Frequency-dependent separation
- Stereo coherence analysis
- Preserves original phase
- Preserves stereo image
- Removed monitoring mode
- Spectrum display
- Reduction display
- Tail visualization
- Six starting presets
- A/B comparison
- Host automation
- Seven tooltip languages
- Scalable interface
- 44.1–192 kHz support
- VST3
- AU
- AAX
- Apple Silicon
- Intel Mac
- Windows
- 14-day full demo
- One-time activation
- No permanent internet connection required
Potential Limitations
Deverb is not magic, and Orra Audio is commendably clear about that.
It cannot completely reconstruct a dry recording from every reverberant source.
The most important limitations are:
- Early reflections within roughly the first 40 ms remain
- Small-room coloration may therefore remain
- Dense sustained material is difficult to separate
- Strong settings can shorten natural instrument releases
- Very long reverbs above three seconds are treated as three-second rooms
- Delays and echoes are not removed reliably
- It is not a noise-reduction plugin
- It introduces 2048 samples of latency
Those limitations are not necessarily weaknesses.
They are a realistic description of what single-track de-reverberation can and cannot accomplish.
Final Verdict
Orra Deverb is a remarkably thoughtful free restoration tool.
What makes it particularly attractive is not just the ability to reduce reverb, but the way Orra Audio has made a technically complicated process understandable.
You can simply press Scout, play a section containing a few phrase endings, let the plugin estimate the room and then use the main Reduction control to decide how dry the result should become.
More experienced users still have access to useful controls over:
- Decay
- Reverb level
- Preservation
- Frequency focus
- Smoothing
- Maximum attenuation
And the Removed monitoring mode provides an excellent safeguard against over-processing.
The underlying approach is also refreshingly transparent.
Orra Audio openly explains that early reflections remain, dense material cannot always be separated and aggressive settings can affect natural releases.
That honesty is preferable to claiming that every reverberant recording can somehow be transformed into a perfectly dry studio take.
For vocals, dialogue, instruments, old recordings and samples captured in spaces with too much ambience, Orra Deverb is absolutely worth adding to a restoration toolbox — particularly since it can be licensed completely free.
