Calibra VST3 Headphone/Monitoring Calibrator - Windows and macOS

[jumper981]

Hi everyone,

I wanted to share a project I’ve been working on called Calibra.

It’s a VST3 plugin for Windows and macOS made for headphone calibration, phase control and monitoring directly inside the DAW.

I originally built it for my own workflow because I wanted one plugin that could handle the kind of headphone correction files I actually use, without having to jump between different tools.

Calibra supports TXT correction files, including common Equalizer APO / AutoEQ-style files, with support for:

• Preamp
• Filter
• GraphicEQ
• Include
• enabled / disabled filters
• parametric EQ filters
• graphic correction curves
• relative include paths
• decimal comma parsing

It also supports FFP preset import and export and conversion.

Passes null-test with Eq-APO.

The current correction modes are:

• IIR Minimum Phase (0 Latency)
• FIR Minimum Phase (0 Latency)
• FIR Natural Phase
• FIR Linear Phase

So depending on the situation, you can choose between low-latency minimum-phase correction, FIR-based correction, a more natural phase/ringing compromise, or linear-phase FIR with host-compensated latency.

I also added the monitoring tools I personally wanted to have in the same plugin:

• A/B calibration slots
• crossfeed with 5 hardware-based presets and custom controls
• input gain
• pan
• stereo width
• bass side cut
• Stereo / Left / Right / Mid / Side monitoring
• panic / safety mute
• project recall with embedded correction snapshots

The A/B slots are useful for comparing two headphones, two correction files, two target curves, measured vs AutoEQ correction, or different phase modes without constantly reloading files.

The crossfeed is intended as a practical headphone monitoring tool. It is not meant to create a fake room or exaggerated stereo effect. It is there to reduce the very hard left/right separation that can happen on headphones, especially during longer sessions.

Project recall was also important to me. Calibra can store the applied correction snapshot inside the DAW project, so a session can still recall the calibration even if the original correction file has been moved, renamed or deleted.

I’m also starting to upload my own headphone measurements, and I’d like to use Calibra as part of a broader measurement, correction and headphone research workflow.

The plugin is paid, but I want to be transparent about why.
I’m an electronics engineer, and I would like to reinvest anything I make from this project into better headphone measurement equipment, ideally something like a B&K 5128 or a similarly serious setup.

For me, that would not just be about making “better graphs”. The goal is to study headphones more seriously, build a larger and more reliable set of measurements, understand their behavior better, and eventually use that knowledge for actual headphone design and development.
It would also allow me to expand Calibra over time with more measurement-based workflows and more useful correction resources.

Calibra is currently in early access, so I’d like to offer multiple free licenses to people willing to test it and send useful feedback.

I’m especially interested in:

• DAW compatibility
• Windows and macOS testing
• real TXT correction files
• Equalizer APO / AutoEQ-style workflows
• A/B slot switching and recall
• project recall
• crossfeed feedback
• bugs, crashes or strange host-specific issues

I’m not looking for forced positive reviews. Honest feedback is much more useful at this stage.

Just contact me and i'll send you the installers.
This page and the itch.io page when will be published will be updated with actual measurements.

If you’re interested in testing Calibra, just contact me and i'll send you the installers with a free license.

Thanks!

 

[jumper981]

EDIT:
LINK: https://iteritas.itch.io/calibra

 

[jumper981]

*Demo now available for everyone

 

[ShadowBoxer]

Just curious, are there internal architectural design aspects that would preclude the filters from being utilized with speakers as opposed to the target of headphones?

 

[phoenixdogfan]

Interesting. One thing I would like to see is a variable user controlled test tone to manually eq the phones while they are on ear. I think a tool like that would be especially helpful in building filters for ear canal resonances. Maybe that's already a part of the calibrator, but it would be interesting to have it, I know I would certainly use it on my IEMs. I already use that kind of tool on my Smyth A16 Realiser since its built in, and after I do EQ on the phones with the supplied in ear mics, it then take them out and use the manual part to find the ear canal resonance.

 

[jumper981]

Just curious, are there internal architectural design aspects that would preclude the filters from being utilized with speakers as opposed to the target of headphones?

Not really — there’s nothing in the internal architecture that specifically prevents using the filters with speakers.

For example, in my own setup I’m using my KH150 monitors on the A side and my LCD-X on the B side, so I can switch between speaker and headphone correction inside the same instance/workflow.

 

[thon]

*Demo now available for everyone

The Mac version does not contain a *.vst3 file

 

[jumper981]

Interesting. One thing I would like to see is a variable user controlled test tone to manually eq the phones while they are on ear. I think a tool like that would be especially helpful in building filters for ear canal resonances. Maybe that's already a part of the calibrator, but it would be interesting to have it, I know I would certainly use it on my IEMs. I already use that kind of tool on my Smyth A16 Realiser since its built in, and after I do EQ on the phones with the supplied in ear mics, it then take them out and use the manual part to find the ear canal resonance.

That’s actually a good idea. I need to investigate the ear-canal side of this a bit more and think about whether there’s a practical way to implement it without making the workflow too complicated.
At the moment, Calibra lets you load existing Equalizer APO / Peace / AutoEQ-style filters, but the current workflow is mostly based around applying a correction that has already been prepared externally, rather than interactively building or modifying the response inside the plugin.
A user-controlled tone or sweep tool for manually finding resonances and modifying the response could be very useful, especially for IEMs, but it would probably require some redesign of the calibration workflow.

 

[solderdude]

Something to ponder on... corrections are based on measurements of headphones on certain standard test fixtures.

The generated plots on any of these fixtures can differ because of.
A: different standards
B: different targets
C: different positioning
D: different pad wear
E: different seal
F: for IEMs insertion depth and ear canal shape

This means that any generated EQ will depend on any combination of the mentioned aspects.
Also how many ears actually conform to the few measurement standards that exist.

In general all headphones will need some EQ and even when not perfect will mostly lead to an improvement of tonality.

 

[jumper981]

The Mac version does not contain a *.vst3 file

Yes, that is normal on macOS.

The .vst3 is technically a plugin bundle, so depending on how you view it, it may appear as a folder. You should not open it or move only the contents inside it — you need to move the entire Calibra.vst3 bundle/folder into your VST3 plug-ins folder:

/Library/Audio/Plug-Ins/VST3

or, for user-only installation:

~/Library/Audio/Plug-Ins/VST3

Then restart or rescan your DAW.

 

[thon]

Yes, that is normal on macOS.

Normal: not at all.
But it works, yes.

 

[jumper981]

I also ran some basic technical checks in PluginDoctor and check Equalizer-APO null-test.

RED is FIR Linear Phase and PINK it's IIR (FIR Minimum Phase it's basically the same).

These are not headphone measurements, but software validation tests to check that Calibra loads and applies correction files correctly.

The Equalizer APO null-test setup shows that, with a compatible TXT correction file, Calibra can reproduce the same correction inside the DAW.

In PluginDoctor, the magnitude response confirms that the loaded LCD-X correction file is applied as expected. The IIR and FIR modes can match the same target magnitude response, while offering different phase, impulse-response, latency and ringing behavior.

The THD/IMD plots are mainly sanity checks: Calibra is a linear correction plugin, so the distortion stays around the numerical/noise floor of the test setup.

Basically transparent.